bluuebunny/crossref_metadata_2025 huggingface dataset:
25 year perspective Aspects of strain and strength measurement in miniaturised testing for engineering metals and ceramics
Authors: Lord J. D. , Roebuck B. , Morrell R. , Lube T.
Published: February 2010

Testing in the microregime is relevant to many technological issues, including, for example, evaluating the performance of established plant or new components through removal of small scale samples; assessing point to point variation in welded structures; characterising expensive advanced alloys that typically are only available in small quantities; and testing of subsized components. The use of miniature testpieces requires attention to the scale of the underlying microstructure relative to the overall testpiece dimensions, and presents challenges to the measurement of stress and strain in small volumes. The subject is extensive and the emphasis of the current paper is on a discussion of issues associated with the measurement of strength and strain, particularly with the latter assessed using non-contact optical techniques based on digital image correlation. The current article thus concentrates on the testing situation at the intermediate scale (in the range 0·5–5 mm) where testpieces are small compared with the size of engineering components and in the range where representative mechanical behaviour of the underlying microstructure must be considered. Metrology issues are addressed through specific case studies concerning; microuniaxial tests; small punch tests; subsized ceramic strength tests and the microindentation technique. Particular attention is paid to the uncertainties in measurement arising from the use of microscale tests to provide quantifiable levels of confidence in the ability of such tests to discriminate material behaviour.
Settlements and countryside of Messenia during the late Middle Ages: the testimony of the fortifications
Authors: Kontogiannis N. D.
Published: February 2010

The various groups of fortifications that were in use in Messenia during the period of the thirteenth to fifteenth centuries are examined. Five categories are distinguished based on their position, size and defensive features. It is concluded that the fortifications were directly linked to the new social and political reality that prevailed in the area between the dismantlement of the Byzantine empire in 1204 and the Ottoman conquest in the second half of the fifteenth century.
Landholding and landscape in Ottoman Cyprus
Authors: Given Michael , Hadjianastasis Marios
Published: February 2010

In Ottoman Cyprus (1571–1878), social organization was based above all on the ownership and exploitation of agricultural land. The social relations, economic processes and daily practices of landowning elites and peasant farmers alike were structured by their relationship with the land. In this article, historical and archaeological data are integrated in order to investigate the development of social organization by focusing on landholding and landscape. In particular, it examines the role, identity and material culture of the new Cypriot/Ottoman elite, the commercialization of agriculture as expressed in the economy and the landscape, and the daily routine experiences of communities in the landscape.
Property and morality: women in the communal courts of late Ottoman Greece
Authors: Doxiadis Evdoxios
Published: February 2010

Women in Ottoman Greece were present in a number of different courts of law, one being the so-called communal courts. These courts became increasingly important towards the end of the Ottoman period, especially in areas where there was little if any Muslim population, and they dealt with a great variety of cases ranging from property disputes to rape and crimes of morality. Women were very active in such courts, both as accusers and as accused, showing remarkable knowledge of the manner in which such courts functioned. They frequently chose to pursue cases in them, in part because communal courts were supportive of individuals in difficult circumstances such as widows, who form the bulk of the female petitioners. This was an outcome of the nature of these courts which were composed of the same individuals who exercised executive powers over their communities and who thus wanted to ensure tranquillity and the prosperity of their people. For that reason notables appear almost unconcerned with the stipulations of customary law in several of their judgments, seeking instead to achieve compromises, or what we could term the greater social good. Being local, easily accessible, and familiar to the members of each community, communal courts were attractive to women and men in the years leading to the emergence of the modern Greek state, forming one tier of the complex Ottoman ‘system’ of conflict resolution.
Saint Sebastian: the martyr from Milan in post-Byzantine wall-paintings of the sixteenth and seventeenth centuries and the influences from Western painting
Authors: Proestaki Xanthi
Published: February 2010

St Sebastian entered the thematic repertoire of post-Byzantine mural painting from the West in the sixteenth and seventeenth centuries. Two main iconographic types are encountered in post-Byzantine wall-paintings, both of them popular in Western art: The Ordeal of the Arrows and St Sebastian after the Martyrdom. The influences of Italian models on the iconography are obvious. Nonetheless, the loans from Western iconography and Renaissance art concern a limited number of scenes and subjects, because the post-Byzantine painters tried to renew painting within the framework of Orthodox tradition and its doctrinal content.
The doubling of the self in the private diaries of Ion Dragoumis, George Seferis and George Theotokas
Authors: Falagkas Nikos
Published: February 2010

The ‘doubling of the self’ is a phenomenon that appears in entries of private diaries and consists in the division of the diarist’s self into two: the self that acts and the self that observes and writes. This phenomenon can be found in Dragoumis’ Φύλλα ημερολογίου, Seferis’ Μέρες and Theotokas’ Τετράδια ημερολογίου. There are entries where the doubling of the self occurs in practice and entries where it is described, discussed or analysed. All these reveal the three Greek diarists’ contradictory feelings about the doubling of the self, but also the latter’s significance for the private diary.
Juan Fernández de Heredia’s History of Greece
Authors: Luttrell Anthony
Published: February 2010

The Aragonese Hospitaller Juan Fernández de Heredia, Master of Rhodes from 1377 to 1396, was an outstanding patron of historical compilations, all of them translated into Aragonese. He promoted the earliest translations into any western language of Plutarch’s Lives, of parts of Thucydides and of Zonaras’ Epitome of Byzantine history; he also produced a version of the Chronicle of the Morea with an entirely original section which covered much of the fourteenth century. These and other sources in his corpus formed the basis for a unique initiative, a continuous history of Greece.
Predicting optimum hollowness of normally loaded cylindrical rollers using finite element analysis
Authors: Abu-Jadayil W. M. , Khraisat W. A.
Published: February 2010

Fatigue life investigations have been made for hollow rollers in pure normal loading. Different hollowness percentages between 20 and 80% have been tested to find the optimum percentage hollowness that gives the longest fatigue life. Two main models were built for this purpose: model 1 with two identically sized rollers and model 2 with two non-identically sized rollers. In each model, two cases have been studied: when both rollers are hollow and when one roller is hollow while the other one is solid. The Ioannides–Harris (IH) theory was used to calculate the relative fatigue life of the hollow rollers with respect to solid rollers under the same loading. Investigations have been made for five different materials: CVD 52100, carburised steel, VIMVAR M50, M50NiL and induction hardened steel. The finite element package ABAQUS has been used to study the stress and deformations in the loaded rollers. In general, the optimum hollowness percentage with the longest fatigue life ranges between 60 and 70% based on the kind of the material, whether the rollers are of the same or different size and whether one or both rollers are hollow. Using the IH theory for fatigue life calculation resulted in having infinite fatigue life for those rollers made of induction hardened steel that relatively has high fatigue limit value. Rollers in the optimum range are flexible enough to get the best redistribution of stress in the contact zone. For models of a hollow cylindrical roller in contact with a solid roller, the optimum hollowness is around 70%. When both cylindrical rollers are hollow, the optimum hollowness decreases between 60 and 65%. At the optimum hollowness, small differences in the fatigue life have been found between models of one hollow roller and models of two hollow rollers, even though having both hollow rollers means less weight, thus saving more material and more stability for the system.
Magmatic and post-magmatic Y-REE-Th phosphate, silicate and Nb-Ta-Y-REE oxide minerals in A-type metagranite: an example from the Turčok massif, the Western Carpathians, Slovakia
Authors: Uher P. , Ondrejka M. , Konečný P.
Published: February 2010

An electron microprobe study of Y-REE-Th phosphate, silicate and Nb-Ta-Y-REE accessory-mineral assemblages revealed the compositional variations and evolution in post-orogenic, hypersolvus Permian A-type metagranite from Turčok, in the Gemeric Unit, of the Western Carpathians, eastern Slovakia. Prismatic zircon I and allanite-(Ce) are primary magmatic phases. However, the late-magmatic to early-subsolidus processes led to the formation of a more complex younger assemblage: bipyramidal zircon II, xenotime-(Y), thorite, gadolinite-hingganite-(Y), Nb-Ta-Y-REE oxide phases [fergusonite-(beta)/ samarskite-(Y), aeschynite/polycrase-(Y), and Nb-rich rutile?] and possibly monazite-(Ce). However, monazite-(Ce) and the partial alteration of allanite-(Ce), xenotime-(Y) and the Nb-Ta-Y-REE minerals are probably connected with a younger Alpine metamorphic overprint of the granite. Thorite appears as a solid solution in the thorite-xenotime-zircon series; it is also enriched in Al. Fergusonite-(beta)/ samarskite-(Y) and especially aeschynite/polycrase-(Y) show increased P, Si and Al contents.
Dalnegroite, Tl5–xPb2x(As,Sb)2l–xS34, a new thallium sulphosalt from Lengenbach quarry, Binntal, Switzerland
Authors: Nestola F. , Guastoni A. , Bindi L. , Secco L.
Published: February 2010

Dalnegroite, ideally Tl4Pb2(As12Sb8)Σ20S34, is a new mineral from Lengenbach, Binntal, Switzerland. It occurs as anhedral to subhedral grains up to 200 μm across, closely associated with realgar, pyrite, Sb-rich seligmanite in a gangue of dolomite. Dalnegroite is opaque with a submetallic lustre and shows a brownish-red streak. It is brittle; the Vickers hardness (VHN25) is 87 kg mm-2 (range: 69—101) (Mohs hardness ∼3—3½). In reflected light, dalnegroite is highly bireflectant and weakly pleochroic, from white to a slightly greenish-grey. In cross-polarized light, it is highly anisotropic with bluish to green rotation tints and red internal reflections.

According to chemical and X-ray diffraction data, dalnegroite appears to be isotypic with chabournéite, Tl5-xPb2x(Sb,As)21-xS34. It is triclinic, probable space group P1, with a = 16.217(7) Å, b = 42.544(9) Å, c = 8.557(4) Å, α = 95.72(4)°, β = 90.25(4)°, γ = 96.78(4)°, V = 5832(4) Å3, Z = 4.

The nine strongest powder-diffraction lines [d(Å) (I/I0) (hkl)] are: 3.927 (100) ( 10 0); 3.775 (45) (22); 3.685 (45) (60); 3.620 (50) (440); 3.124 (50) (2); 2.929 (60) (42); 2.850 (70) (42); 2.579 (45) (0 2); 2.097 (60) (024). The mean of 11 electron microprobe analyses gave elemental concentrations as follows: Pb 10.09(1) wt.%, Tl 20.36(1), Sb 23.95(1), As 21.33(8), S 26.16(8), totalling 101.95 wt.%, corresponding to Tl4.15Pb2.03(As11.86Sb8.20)S34. The new mineral is named for Alberto Dal Negro, Professor in Mineralogy and Crystallography at the University of Padova since 1976.
The crystal chemistry of holtite
Authors: Groat L. A. , Grew E. S. , Evans R. J. , Pieczka A. , Ercit T. S.
Published: February 2010

Holtite, approximately (Al,Ta,□)Al6(BO3)(Si,Sb3+,As3+)Σ3O12(O,OH,□s)Σ3, is a member of the dumortierite group that has been found in pegmatite, or alluvial deposits derived from pegmatite, at three localities: Greenbushes, Western Australia; Voron'i Tundry, Kola Peninsula, Russia; and Szklary. Lower Silesia, Poland. Holtite can contain >30 wt.% Sb2O3, As2O3, Ta2O5, Nb2O5, and TiO2 (taken together), but none of these constituents is dominant at a crystallographic site, which raises the question whether this mineral is distinct from dumortierite. The crystal structures of four samples from the three localities have been refined to R1 = 0.02—0.05. The results show dominantly: Al, Ta, and vacancies at the Al(l) position; Al and vacancies at the Al(2), (3) and (4) sites; Si and vacancies at the Si positions; and Sb, As and vacancies at the Sb sites for both Sb-poor (holtite I) and Sb-rich (holtite II) specimens. Although charge-balance calculations based on our single-crystal structure refinements suggest that essentially no water is present, Fourier transform infrared spectra confirm that some OH is present in the three samples that could be measured. By analogy with dumortierite, the largest peak at 3505-3490 cm-1 is identified with OH at the O(2) and O(7) positions. The single-crystal X-ray refinements and FTIR results suggest the following general formula for holtite: Al7-[5x+y+z]/3 (Ta,Nb)x□[2x+y+z]\3,BSi3-y(Sb,As)yO18-y-z(OH)z, where x is the total number of pentavalent cations, y is the total amount of Sb + As, and z ⩽ y is the total amount of OH. Comparison with the electron microprobe compositions suggests the following approximate general formulae Al5.83(Ta,Nb)0.50□0.67BSi2.50(Sb,As)0.50O17.00(OH)0.50 and Al5.92(Ta,Nb)0.25□0.83BSi2.00(Sb,As)1.00O16.00(OH)1.00 for holtite I and holtite II respectively. However, the crystal structure refinements do not indicate a fundamental difference in cation ordering that might serve as a criterion for recognizing the two holtites as distinct species, and anion compositions are also not sufficiently different. Moreover, available analyses suggest the possibility of a continuum in the Si/(Sb + As) ratio between holtite I and dumortierite, and at least a partial continuum between holtite I and holtite II. We recommend that use of the terms holtite I and holtite II be discontinued.
How low can you go? - Extending downwards the limits of plastic deformation in pyrite
Authors: Barrie C. D. , Boyle A. P. , Salter M.
Published: February 2010

Understanding the deformation mechanisms that may operate in pyrite (FeS2) across a range of P-Tconditions is important in deciphering the history of deformed ore deposits. Pyrite has frequently been considered a hard mineral, which deforms by cataclastic flow or diffusive processes, if at all, at temperatures <425°C. However, utilizing SEM-based orientation-contrast (OC) imaging and electron-backscatter diffraction (EBSD) techniques, plastic deformation can now be readily identified within pyrite grains. In this study, a series of pyrite-rich polymetallic ore deposits, deformed at low temperature metamorphic conditions (∼200—420°C), have been investigated. Results indicate that pyrite grains in all the ore deposits preserve internal lattice ‘distortion’ or ‘bending’ and therefore plastic deformation mechanisms have operated. Many pyrite grains in the ore deposits also contain low-angle (∼2°) sub-grain boundaries or ‘dislocation walls', indicating that both dislocation glide and creep have been the dominant deformation mechanisms at peak metamorphic conditions within the pyrite grains. These results suggest that the brittle-ductile transition in pyrite occurs at temperatures potentially as low as ∼200°C, far lower than implied from previous studies or the current pyrite deformation-mechanism map.
Perovskite from the Dutoitspan kimberlite, Kimberley, South Africa: implications for magmatic processes
Authors: Ogilvie-Harris R. C. , Field M. , Sparks R. S. J. , Walter M. J.
Published: February 2010

Perovskite compositions are used to investigate the relationship between the minor components (i.e. LREE, Fe3+ and Nb) and the oxygen fugacity (fo2) of perovskite in four different kimberlite lithofacies from the Dutoitspan pipe, Kimberley, South Africa, which range from diamondiferous to barren. The perovskite textures and chemical variations provide insight into magmatic and eruptive processes. Some crystals display cores with rims separated by a sharp boundary. The cores contain larger Na and LREE contents relative to the rims, which show a large increase in Fe3+ and Al. The mid-grade and barren kimberlites have bi-modal cores, reflected in the mineral chemistry, signifying multiple batches of magma and magma mixing. The fo2 of the magma is determined by an Fe-Nb oxygen barometer. The most diamondiferous kimberlite has the greatest Fe3+ content and highest fo2 (NNO –3.6 to –1.1). The kimberlite containing large diamonds has the smallest Fe3+ content and lowest fo2 (NNO –5.2 to –3.0). The barren and mid-grade kimberlites display a wide range of fo2,(NNO –5.3 to –1.5) as a result of perovskites forming in different melts and subsequently mixing together. Chemical and petrological evidence suggests that the volatile content, degassing, decompression and rate of crystallization can influence the rate at which the magma is erupted. One possibility is that the most oxidized magma, containing the highest volatile content, is therefore erupted much more rapidly, preserving diamond as a consequence.
Complex relationships among coexisting pyroxenes: the Palaeogene Eskdalemuir dyke, Scotland
Authors: Bagiński B. , Dzierżanowski P. , Macdonald R. , Upton B. G. J.
Published: February 2010

The composite Eskdalemuir dyke was formed by the intrusion of rhyolitic magma into partly crystallized basaltic magma, the proportion of the silicic component increasing towards the dyke centre. The less silicic parts were effectively supercooled and crystallization was halted when the residual melt quenched to rhyolitic glass which constitutes up to 50% of the dyke's centre. Pyroxene compositions in the mixed magma rocks include augite, pigeonite and orthopyroxene of very variable composition. Individual crystals in the matrix as small as 200 μm can contain compositions occupying a considerable part of the Di-Hd-En-Fs quadrilateral. Pyroxene crystallization took place under extreme disequilibrium conditions, as shown by highly variable zonation patterns; apparently opposite zoning trends can occur in adjacent grains. Small-scale variations in melt composition were probably the dominant control over the compositional and textural complexity in the pyroxenes.
Megacrysts and salic xenoliths in Scottish alkali basalts: derivatives of deep crustal intrusions and small-melt fractions from the upper mantle
Authors: Upton B. G. J. , Finch A. A. , Słaby E.
Published: February 2010

Ca-poor and typically Na-rich feldspar megacrysts are common associates of spinel lherzolitic and pyroxenitic xenoliths in Scottish alkalic basalts. Associated megacrysts and composite megacrysts and salic xenoliths include apatite, magnetite, zircon, biotite, Fe-rich pyroxene(s) and corundum. The salic xenoliths and related megacrysts are referred to collectively as the ‘anorthoclasite suite': the majority of the samples are inferred to derive from the disaggregation of coarse-grained, typically Na-rich, syenitic protoliths at depth. Rare occurrences of euhedral anorthoclase megacrysts, together with zircon dating, imply that the suite crystallized at, or very shortly before, their entrainment by the basaltic host magmas. Some evidence suggests that the anorthoclasite suite protoliths lie within ultramafic (pyroxenitic) domains in the deep crust. The latter are inferred to be pegmatites, crystallized from carbonated trachytic magmas with widely variable Ca, Na, K, Ba and trace-element contents, and to have ranged from metaluminous to peraluminous. Crystal zonation and resorption textures within the salic xenoliths imply that the crystallization of the parent magmas was complex. Confirmation of this comes from cathodoluminescence studies of the feldspars showing that early ('primary’) anorthoclases and potassian albites exhibit partial replacement by a more potassic feldspar. A third generation of potassic feldspar (enriched in an assortment of trace elements and deduced to have crystallized from a carbonated high-K melt) forms transecting zoned veins in which carbonate fills the axial zone.

Whereas most of the anorthoclasite suite materials are inferred to have grown from metaluminous magmas, the occurrence of magmatic corundum in salic xenoliths indicates crystallization from magmas that were peraluminous. The corundum-bearing samples also contain Nb-rich oxide minerals and their associated feldspars have the highest rare-earth element (REE)contents. Accordingly, the peraluminous trachyte magmas are deduced to have been specifically enriched in high field-strength trace elements. It is proposed that formation of the anorthoclasite suite protoliths is a phenomenon closely related to that of salic glass ‘pockets', well known from spinel lherzolite xenoliths around the world. Not only are there compositional affinities, but both sets of phenomena appear to have closely pre-empted the ascent of alkali basalt (host) magmas. We propose that the two sets of phenomena are linked and that the anorthoclasite suite derived from coarse-grained sheets, generated by the aggregation of salic melt fractions rising from the shallow mantle and heralding the onset of basaltic magmatism.
Synthetic amphiboles and triple-chain silicates in the system Na2O-MgO-SiO2-H2O: phase characterization, compositional relations and excess H
Authors: Maresch W. V. , Welch M. D. , Gottschalk M. , Ruthmann W. , Czank M. , Ashbrook S. E.
Published: February 2010

The presence of structural OH in amphiboles in excess of the usual two OH per formula has been debated for over 40 years (Gier et ah,1964; Leake et ah,1968). However, the reality of the excess-OH phenomenon is still an open question, because accurate water analyses of amphiboles are rarely available. In this study, we review the data available on the chemically simple synthetic system Na2O—MgO-SiO2-H2O (NMSH) and present new results from NMR, infrared spectroscopy, and X-ray-diffraction that allow re-interpretation of previous studies of NMSH amphiboles along the pseudobinary join between the two end-member compositions Na2Mg6Si8O22(OH)2 and Na3Mg5Si8O21(OH)3.

We show that there is extensive solid solution involving excess H at 650—750°C, but also document the presence of a wide miscibility gap below 600°C. This miscibility gap is defined by amphiboles very close to the end-member composition Na3Mg5Si8O22(OH)3 coexisting with amphiboles with compositions near the ‘normal’ Na2Mg6Si8O22(OH)2 end member.

We also report the characterization of triple-chain silicates (TCS) in the NMSH system and their phase relations with NMSH amphiboles. The upper thermal stability field of the key TCS Na2Mg4Si6O16(OH)2relative to its decomposition to two NMSH amphiboles with a combined equivalent composition has been determined and a pronounced backbend of the transformation boundary documented. Phase relations observed in synthesis experiments suggest that at 550—650°C all TCSs have compositions close to Na2Mg4Si6Oi6(OH)2. Infrared spectroscopy indicates that the TCS synthesized on this composition, studied in detail here, vary from end-member Na2Mg4Si6Oi6(OH)2 to binary solid solutions with less than ∼6 mol.% clinojimthompsonite component. No clear spectroscopic evidence for a ‘Drits’ component NaMg4Si6Oi5(OH)3 (Drits et al.,1975) has been found. Analysis of H2O by vacuum extraction and Karl-Fischer titration indicates large excesses of H2O in all the TCSs studied here that clearly exceed the amounts expected from (OH) groups alone. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) indicate that this excess H2O is structural. We propose that the excess H2O is likely to be molecular H2O located in the ^4-site channels. The observed backbend of the triple-chain decomposition curve is in agreement with a reaction involving dehydration and loss of this molecular H2O. However, the absolute amount of analysed molecular H2O exceeds that expected from the change in Clapeyron slope alone.

While demonstrating the reality of excess OH in amphiboles, the evidence presented in this paper also points to interesting avenues for future research on both amphiboles and TCSs, such as understanding the dynamics and enhanced crystal chemistry of excess OH and molecular H2O in pyriboles.
Experimental investigation of near-liquidus andalusite-topaz relations in synthetic peraluminous haplogranites at 200 MPa
Authors: Clarke D. B. , Wunder B. , Förster H.-J. , Rhede D. , Hahn A.
Published: February 2010

Many evolved peraluminous granite plutons contain either andalusite (Al2SiO5) or topaz (Al2SiO4(OH,F)2), but some plutons contain both of these A/NK [mol. Al2O3/(Na2O+K2O)] = ∞ phases. We present the results of experiments conducted to locate the andalusite-topaz boundary in water-saturated peraluminous haplogranite melts in T-P-Xspace, where T = 700—650°C, P = 200 MPa. andX(A/NK = 1.1, 1.2, 1.3, 1.4, and F = 0, 1, 2, 4 wt.%).The starting materials are synthetic K-Na-Al-Si gels, with added H2O and AgF, with seeds of natural andalusite and topaz, and with run times of 5—7 days. Phase identification is by electron microprobe. All experimental run products contained quartz. For all values of bulk A/NK, F concentrations ⩽ 1 wt.% favour andalusite stability, whereas F concentrations ⩾ 1 wt.% favour topaz stability. For bulk A/NK ⩽ 1.2 and intermediate F concentrations, no A/NK = phase is present; for bulk A/NK ⩾ 1.3, quench or metastable mullite formed. Topaz reaction rims on naturally occurring andalusite, frequency of naturally occurring assemblages, general chemical considerations, and experimental evidence all suggest that some topaz is the product of a peritectic reaction between an early primary magmatic andalusite and a late F-enriched melt. The appearance of such topaz is an important mineralogical expression of F activity in the melt, and may be an indicator for high field-strength Sn-W-U-Mo polymetallic mineralization.
Synthesis, structures, and aromaticity of phosphole-containing porphyrins and their metal complexes
Authors: Matano Yoshihiro , Nakabuchi Takashi , Imahori Hiroshi
Published: February 2010

Our recent studies on the synthesis, structures, and aromaticity of phosphole-containing porphyrins and their metal complexes are summarized. Core-modified P,X,N2-porphyrins (X = S, N) are accessible from a σ4-phosphatripyrrane and the corresponding 2,5-difunctionalized heteroles in a few steps. X-ray structural analysis of the σ3-P,N3 porphyrin revealed that it possesses a slightly distorted 18π plane. The phosphorus atom incorporated at the core plays an important role in producing unprecedented reactivity and coordinating ability for the porphyrin ring. The P,N3 free base reacts with [RhCl(CO)2]2 in dichloromethane, ultimately yielding an 18π P,N3–rhodium(III) complex, whereas the P,S,N2 free base undergoes redox-coupled complexation with zero valent group 10 metals to afford the corresponding P,S,N2-isophlorin–metal(II) complexes. The aromaticity of the free-base porphyrins and the metal complexes was uncovered based on both experimental and theoretical results. It is of particular interest that the P,S,N2-isophlorin–metal complexes exhibit only a weak antiaromaticity in terms of the magnetic criterion.
Allium chemistry: Use of new instrumental techniques to “see” reactive organosulfur species formed upon crushing garlic and onion
Authors: Block Eric , Cody Robert B. , Dane A. John , Sheridan Robert , Vattekkatte Abith , Wang Kai
Published: February 2010

Three different instrumental methods have been used to examine the organosulfur chemistry of intact and cut garlic and onions: X-ray fluorescence spectroscopic imaging (XFS), direct analysis in real time (DART) mass spec-trometry, and ultra-performance liquid chromatography-(Ag+)-coordination ion spray mass spectrometry (UPLC–(Ag+)CIS–MS). The first technique has been used to map the location of different chemical forms of sulfur in intact and damaged onion cells, the second technique, to identify the reactive, volatile sulfur compounds formed on cutting the plants, and the third technique, to identify members of families of polysulfides found in the distilled oil of garlic.
Molecular tweezers for fullerenes
Authors: Pérez Emilio M. , Martín Nazario
Published: February 2010

The search for molecular receptors capable of forming stable associates with fullerenes is a very active field of research in fullerene chemistry, with the purification from fullerite and the self-assembly of nanoscale electronic devices as driving forces. The construction of bivalent, tweezer-like receptors featuring two recognizing units connected through a spacer is one of the most successful design strategies employed in this field. Here, we present an overview of the most significant examples of these “molecular tweezers” for fullerenes.
Polyfluorinated ligand-supported organometallic complexes of copper, silver, and gold
Authors: Dias H. V. Rasika
Published: February 2010

The tris(pyrazolyl)borate [HB(3,5-(CF3)2Pz)3]− prepared using highly fluorinated 3,5-bis(trifluoromethyl)pyrazole and BH4− is an excellent supporting ligand for the stabilization of a number of rare organometallic complexes of coinage metals. For example, it has enabled the isolation of Cu(I), Ag(I), and Au(I) complexes of CO and ethylene as crystalline solids. Syntheses, spectroscopic and structural features, and properties of [HB(3,5-(CF3)2Pz)3]ML (M = Cu, Ag, Au; L = CO, C2H4) are the main focus of this discussion. Several metal adducts based on the tris(triazolyl)borate [HB(3,5-(CF3)2Tz)3]− supporting ligand as well as the cationic, coinage metal multi-alkene complexes containing the [SbF6]− counterion are also discussed.
Iron carbenoid-mediated ylide reactions
Authors: Sun Xiu-Li , Zheng Jun-Cheng , Tang Yong
Published: February 2010

Electrophilic metal carbenoids, readily available from diazo compounds, prove to be good reagents for the preparation of ylides under neutral conditions. We have extended the strategy to synthesize allenes from diazoacetates with both stable and unstable ketenes in the presence of PPh3 and Fe(TCP)Cl (0.5 mol %), which provided an easy access to optically active 4,4-disubstituted allenic esters by employing enantiopure phosphines. The mechanism involving the generation of ylide through catalytic transfer of an iron(II) carbene to phosphine was confirmed. A tandem Wittig–Nazarov cyclization reaction was further developed based on these results, culminating in a straightforward method for the construction of β-methylenecyclopentenones in a multistep one-pot manner without isolation of inter-mediates. By combining AsPh3 and iron carbenoids, a catalytic Wittig reaction in toluene/water biphasic system was accomplished, affording α,β-unsaturated esters in high yields with E/Z above 50/1. Surprisingly, crotonate-derived phosphorus ylide reacted with electrophilic iron carbenoid, affording 1,1,4-trisubstituted 1,3-butadienes with high regio- and stereo-selectivities, where a new ylide generated via formal intermolecular carbenoid insertion into olefinic C–H bonds of the crotonate-derived phosphorus ylide was proposed.
Heteroatoms moving protons: Synthetic and mechanistic studies of bifunctional organometallic catalysis
Authors: Grotjahn Douglas B.
Published: February 2010

Improved organometallic catalysts resulting from including ligands capable of proton transfer or hydrogen bonding are described. Pyridyl- and imidazolylphosphines accelerate anti-Markovnikov alkyne hydration and alkene isomerization and deuteration by factors of 1000 to more than 10 000. Evidence for proton transfer and hydrogen bonding in catalytic intermediates comes from computational, mechanistic, and structural studies, where 15N NMR data are particularly revealing.
Asymmetric synthesis of aminophosphonic acids mediated by chiral sulfinyl auxiliary: Recent advances
Authors: Łyżwa Piotr , Mikołajczyk Marian
Published: February 2010

New approaches to asymmetric synthesis of α-, β- and γ-aminophosphonic acids using enantiopure p-toluenesulfinimines as key reagents are reported. The utility of the devised methods is illustrated by the syntheses of enantiomeric aminophosphonic acids such as AP4, AP3, and its 3-amino isomer.
Integrated Logging while Drilling and Wireline Borehole Imaging Applications in Offshore Nile Delta Reservoirs
Authors: Hassan Saad , Biagi Mario , Mohie Mohamed , Fasto Alessandro , Juandi Dedi , Abuelfotoh Ahmed , ElFouly Mai A. , Emam Mahmud
Published: February 2010

Combining logging while drilling (LWD) azimuthal density images from real-time measurements with wireline electrical borehole imaging logs minimizes risks, maximizes data acquisition, and creates a better understanding of reservoir characteristics than using either of the tools alone. The azimuthal density images provide structural images in real time, but not fine sedimentary details. Meanwhile, wireline electrical borehole images fill in detail in stratigraphic dip analysis. Comparing the median grain size derived from core sieve analysis with the pseudo median grain size derived from the image resistivity distribution of wireline electrical borehole imaging data confirmed that the results are comparable and wireline electrical borehole image can substitute core analysis in some extent to extract some textural information from sands.
Optimizing Waterflooding Considering Dip in the Wafra Field
Authors: Chang Ming-Ming , Cullen Rafael , Utomo Bagio , El-Gendt Osamal
Published: February 2010

Located in Partition Neutral Zone over Kuwait and Saud Arabia border, Wafra Ratawi is a carbonate reservoir having formation dip ranging from 0.5 to 3.5 degrees at edge of the field. Waterflood is to be implemented by new injectors or converting producers to water injectors. Reservoir studies were undertaken to determine whether inject down-dip or in a central location. While the down-dip injector has gravity advantage in displacement process, the central injector may support other four producers no more than two rows away. A reservoir simulation model suggested converting the central producer over the immediate down-dip well at a reservoir edge of 0.9° dip. Reasons to draw this conclusion is not clear due to a complicated reservoir structure in this area. A five-well simulation sector model was therefore taken to investigate this issue.

This study derived a correlation of recovery as a function of dip angle, relative permeability, edge aquifer strength, and injection to production ratio. The model results showed that the central injector performs better than the down-dip injector in a five-well line drive pattern when Ratawi formation dip was less than 2.6 degrees. The central well in the five-well line drive was then converted to an injector in the Ratawi reservoir. The other four producers responded to injection with prompt increase in production and pressure, demonstrating a successful water injector conversion.

This study explained the impacts of formation dip and injector location on wterflood recovery. The derived correlation helped the reservoir management team optimize recovery by selecting the injector location as a function of the reservoir dip.
Challenge in Managing and Optimizing Well Intervention Activity in Matured Oilfield: Approach Taken by Petronas Carigali Sdn Bhd in Accelerating the Capability and Efficiency
Authors: Hashim M Shahrizal
Published: February 2010

Well Intervention activity has become the main activity to ensure production sustainability and ensuring continuous reservoir management plan is properly captured especially for the low reserves field which striving to lower down the Unit Production Cost (UPC). In order to ensure higher job implementation efficiency and reduce the job failure percentage, proper field management has become the most crucial part. Inline with the aspiration, Petronas Carigali Sdn Bhd (PCSB) has established the new sections which are specifically looking for the improvement in well intervention activity which cater the HSE, field management, cost optimization and technical deliverability aspect.

From the total well intervention involved, slickline intervention are the main continuous activity in the region, however there is no specific do and don’t guideline available in the system. Besides, there is also number of coiled tubing and electric line intervention in the locations which possibly contribute to the failure during the job execution. By looking at those activities, the team has established the Technical Bulletin which contain the technical and HSE alert that was shared among all the PCSB fraternity. The bulletin was also shared to all related contractor to ensure its being followed by all parties. The team also focused on any non-routine and new technology or best practices activity implementation by continuously performed further analysis on any non-routine well intervention activity i.e. through tubing cement job, perforation, scale cleanup, etc. which contribute to the cost saving and production delivery to the organization. They internally established the useful Christmas tree health monitoring database in order to optimize the costs which are capable to track the current surface equipment condition inline with Well bore Risk Management (WRM) manual.

This paper discussed on the detailed function and contribution of the newly section development in PCSB that giving positive impact to the organization by showing their capability of optimizing the existing source in order to improve the well intervention efficiency.
Application of Chemical Tracers in IOR: A Case History
Authors: Asadi Mahmoud , Shook G. Michael
Published: February 2010

Secondary recovery is a process in which reservoir fluid is mobilized and moved from an injection well toward a production well. The success of this process greatly depends on the knowledge of reservoir continuity and uniformity, in terms of fluid transmissibility, and how much of the reservoir fluid volume can be contacted by the injection fluid. In any water/gas flood injection project, fluid channeling through mini-fractures, faults, and high permeability streaks results in problems such as poor reservoir sweep efficiency and low hydrocarbon recovery. Therefore, knowledge of direct communication between the injection and production wells as well as an understanding of formation heterogeneity can be of great help to overcome these problems. While techniques such as seismic, mapping geological deposition and reservoir simulation provide valuable information about the feasibility of secondary recovery projects, tracer testing is the only available method that provides valuable information on direct communication, flow-path, and formation heterogeneity across the injection and production wells. This paper presents a detailed review of chemical tracer applications in IOR with a supportive case history from a water-flood field. The paper also presents interpretation and discussion of the results on direct communication identification, formation heterogeneity evaluation, and swept pore volume calculation.
New Incubated Pseudomonas Aeruginosa Bacteria for Increasing Oil Recovery under Reservoir Conditions
Authors: Samir M.. , Abu El Ela M.. , El Marsafy S.. , El Tayeb S.. , Abdel Waly A.. , Sayyouh M. H.
Published: February 2010

Laboratory studies show the existence of some strains of bacteria in field crude oils and formation waters. This work is concerned with studying the effect of the reservoir conditions such as temperature, salinity and lithology on the indigenous bacterial activities. Such study is an original contribution to the knowledge of microbial enhanced oil recovery (MEOR).

Egyptian MEOR project at Cairo University succeeded to isolate a surfactant-producing microorganism "Pseudomonas Aeruginosa" from crude oil produced from an Egyptian oil field. Several displacement tests were conducted in sand pack model. A modified media was used to incubate and improve the growth rate, behavior and stimulation of Pseudomonas Aeruginosa.

The results obtained from the current work showed that Pseudomonas Aeruginosa succeeded to increase the oil recovery by 20%. Pseudomonas Aeruginosa becomes able to resist the effect of temperature up to 70°C and salinity up to 150,000 ppm, when a specific incubation technique is applied. There is no significant effect on the behavior of the bacteria in the presence of the Dolomite and Kailinite inside the reservoir. The value of the oil recovery factor in case of incubation of the bacteria outside the model is greater than its value in case of incubation inside the model by about 5%.

The results obtained are discussed and analyzed in terms of surface tension, hydrogen ion concentrations, viscosity, and conductivity of the effluent solutions.
Reservoir Pathway Identification in a Fractured Carbonate Heavy Oil Reservoir
Authors: Samir M.. , Hassan W.. , Omara M.. , Thabet E.. , Abugreen Y.. , Joshi S..
Published: February 2010

The first production log in heavy oil in Egypt through y-tool, using a high capacity ESP pump, in an open hole completion was performed recently by Scimitar Production Company in Issaran heavy oil field. The objective of the job was to identify the source of water, evaluate the contributions from the different open hole zones and determine whether or not there is cross flow in this fractured heavy oil carbonate reservoir. These wells had originally not been completed with y-tool. Therefore a special y-tool with high capacity ESP was designed especially for Scimitar by Zenith to be able to log the wells under special dynamic conditions. This was the first application world wide of this y-tool, which was used as a temporary completion in the wells.

Production logging (PL) was successfully carried out in 3 Issaran wells at different rates, to identify the high permeability (super-K) layers dominating production and calculate their pressure/PI. Likewise flow profiles were determined and high water producing layers identified. Shut in surveys were successful in detecting cross flowing layers. Calculated flow profile results matched well with surface measured rates.

PL results had a significant effect upon the Issaran field development plan. Water was found to be produced from layers having resistivity up to 30 ohm-m. This led to an increase in the resistivity cutoff for hydrocarbon production and a reduction in water cut. Hydrocarbon producing zones were better identified and Scimitar decided to abandon open hole completions in future wells and go in for cased hole completions, in order both to control the water production as well as avoid breakthrough of injected steam.

This paper describes the field and gives details on job planning, operations, results and way forward for field re-development.
Overview of Tight Gas Field Development in the Middle East and North Africa Region
Authors: Shehata Ahmed , Aly Ahmed , Ramsey Lee
Published: February 2010

As gas demand rises and operators turn to Unconventional gas reservoirs for new supplies, the need to optimize the capacity and recovery potential from this type of reservoir has risen. These Unconventional gas reservoirs represent a vast, long-term, global source of natural gas and have not been appraised in any systematic way. Unconventional gas resources—including tight sands constitute some of the largest components of remaining natural gas resources in the Middle East and North Africa. There is an emerging focus on tight gas reservoirs in the Middle East and North Africa to feed the growing energy needs in this region and save the oil from conventional resources for export and generation of hard currencies.

The greatest challenge for tight gas is to generate economic flow, so technical capabilities are needed for effective development and production of tight gas reserves, such as mineralology/geology, geomechanics, petrophysics, well engineering, and hydraulic fracturing.

During the last decade, 3-D seismic, horizontal drilling, and improved fracture stimulation have had significant impacts on tight gas production in many basins in the Middle East and North Africa.

In this paper we will present a documentation of all the tight gas reservoirs available in the Middle East and North Africa, the challenges of developing these difficult resources, the role of modern technologies in managing tight gas and improving recovery factors, and highlight the best strategies for field development in tight gas reservoirs to capitalize on the promising potential of these reservoirs.

The objective of this paper is to prepare data base to document all the tight gas reservoirs in the Middle East and North Africa and study the impact of technology on tight gas reservoir development in the emerging region.
Difficulties in Using Geostatistical Models in Reservoir Simulation
Authors: Rasouli V.. , Tokhmechi B..
Published: February 2010

Number of estimators and simulators is used in petroleum engineering applications in order to model the static and dynamic characteristics of hydrocarbon reservoirs. However, the fundamental concepts used in estimators and simulators do vary from each other leading to the necessity of choosing the optimal approach with an extensive care. Geostatistics is perhaps the most widely used technique in simulation which is popularly used in different engineering applications and specifically in reservoir simulation. In this paper, three shortcomings of geostatistics in estimation and simulation are highlighted and alternative methods are proposed. Firstly, Kriging estimator, as is used in geostatistics, guarantees minimum estimation variance if the variogram model is the optimum fit and stationary conditions are met. However, in real situation, these conditions are not always satisfied. Geostatistics is prone to number of deficiencies some of which are discussed in this paper in the context of oil and gas applications and alternative solutions are presented. As such, the incapability of variogram, as being the fundamental tool in geostatistical analysis, in capturing the periodic structure of reservoir formation is shown. Then, it is discussed why the use of signal decomposition tools such as Fourier, fast Fourier and wavelet transform is more advantageous than variogram in this context. Secondly, to overcome the smoothing property associated with geostatistics fractal simulation is recommended as an alternative approach. Finally, it is discussed how intrinsic properties of reservoir can be included in multi-fractal or neural network to improve the estimation and simulation process. This appears to be difficult to apply if geostatistical approaches are used for estimation or simulation purposes.