SE Axis Research Articles

Analysis of the processing simulation results and the stress-strain behaviour of low-stiffness brittle workpieces

This scientific article is concerned with an effect of a technology factor that consists in the number and characteristics of microcracks resulted from grinding and polishing on the stress-strain behaviour and displacements of the sensing element’s moving parts. Microcrack dimensions, sizes, and relative positions after processing finishing operations were determined using an atomic-force microscope. An effect of a single microcrack was studied; its affected zone was established. The microcrack arrangement was set in 10 different ways. The most typical microcrack arrangements having the greatest impact on the item’s stress-strain behaviour in their location zone were selected. The item fixing conditions were the same for all cases. This was followed by calculation by the finite element method, for each individual case; the results were recorded in a table. Calculations were carried out for the second mode of the sensing element’s oscillations. The obtained results were used to build plots and draw conclusions on the effect of microcracks formed during the item fabrication. It was established that the farther the microcrack from the SE axis of symmetry, the lower the stresses in its location zone. The tangential arrangement of the microcrack had a greater impact than the radial one. A conclusion was drawn that it was necessary to increase the SE processing quality in the vicinity of a leg where the effect of microcracks is at the maximum. Thereafter, tasks were determined for further study of microcracks’ impact on the item reliability. In theend, a reference list consisting of 12 titles was compiled.

Variation in lineage 2 strain of Lassa fever virus in Nigeria

Background: Nigeria is one of four countries endemic for Lassa fever (LF) in West Africa and harbours three of the four established lineages (strains) of LF. Lineages 2 and 3 occur dominantly in the southern and Northern regions of the country respectively. In the southern region, the South central (S.C) and South east (S.E) axes are most endemic for LF in the southern region. The disparity in complications, morbidity and subsequent mortality (CFR of 30% of S.C cases versus 48% of S.E cases) raised the question; Are there any variations in the LF strains in the SC and SE axes? Methods & Materials: Following the 2014 epidemic with fifteen positive cases in the SE axes, genomic studies elucidating their nucleic acid sequences were conducted in NUITM. A ten year study of nucleic acid sequences of lineage two strains of LF from Nigeria covering the period 2004-2014 gleaned from the GENBANK pool was conducted. To this was added the fifteen positive samples of 2014, totalling 79 LF glycoprotein precursor (GPC) gene sequences. Using MEGA 6 software, phylogenetic and BLAST analysis of the homologous identity of all the 79 strains were conducted. Results: Fifty of the 79 LF lineage two strains were of SC origin while 29 were of SE. Three distinct clades of the SE strain were observed and clustered around Nig 05-SE40, Nig 08-04 and Nig 11-186 strains. Diversity among the clades of the SE strains ranged between 18 – 21%. Perhaps there is a new clade developed every three years in the SE axis. The SC strains were essentially of one clade and exhibited good homologous identity of 97-100%. This suggests less diversity of the SC strains than the SE strains. The SC and SE strains strains exhibited diversity of up to 20%. Conclusion: The Lineage 2 strain has four clades, with 3 of the clades belonging to the strain from the SE axis. This may explain the worse CFR of LF cases in SE axes. The SC strains are essentially of one clade. There is need to evaluate for Ribavirin resistance and/or mutation among clades of SE origin

Biserica evanghelică din Saschiz, judeţul Mureş. Cercetări arheologice (II): cimitirul exterior / The Evangelical church at Saschiz, Mureş County. Archaeological research (II): the cemetery around the church

Articolul analizează mormintele descoperite în exteriorul bisericii evanghelice din Saschiz, completând, astfel, datele publicate anterior despre acest monument. Cercetarea arheologică, realizată cu ocazia restaurării, a identificat câteva zeci de morminte, dispuse neregulat în jurul bisericii. Necropola este rarefiată, mormintele sunt repartizate inegal, iar suprapunerile sugerează existența unor locuri de înmormântare familiale. Ritualul de înmormântare este simplu, toți decedații fiind depuși în poziţie culcat pe spate, cu antebrațele așezate în diferite poziții pe bazin sau abdomen. Un aspect interesant este acela că majoritatea mormintelor nu au respectat orientarea tradițională cu capul către vest, fiind influențate de orientarea bisericii, puternic deviată pe axa NV– SE. Niciunul dintre morminte nu a avut obiecte de inventar, drept urmare limitele cronologice ale cimitirului au fost stabilite pe baza datării edificiului religios, a absenței înmormântărilor anterioare acestuia și a studiului stratigrafic. Conform acestor factori, înhumările au început cel mai devreme după mijlocul secolului al XV‐ lea și au încetat după aproape un secol. Caracteristicile topo‐ cronologice ale cimitirului arată că funcția funerară a bisericii a fost de scurtă durată și accesibilă unui număr restrâns de enoriași, cel mai probabil proveniți din familiile reprezentative ale comunității. Astfel, cercetările arheologice de la Saschiz au documentat o situație destul de rar întâlnită în mediul coloniștilor, în care cimitirul parohial a funcționat, în jurul anului 1500, în alt loc decât biserica.

Folding and faulting in the Chalk at Dykes End, Bridlington Bay, East Yorkshire, resulting from reactivations of the Flamborough Head Fault Zone

Summary: At Dykes End, Bridlington Bay, [National Grid Reference TA 216 692], a 200 m section of Chalk cliffs exposes folds with NW–SE-trending axes and north-eastward thrusting, accompanied by dome and basin structures in the foreshore, structures that are not exposed elsewhere in this region. The folding and thrusting resulted from transpression emanating from sinistral strike-slip reactivations of a right-hand bend, giving a local ESE–WNW trend, in the major E–W Langtoft Fault within the pre-Chalk basement just to the south. The northern side of the fault displaced westwards, underthrusting the Chalk cover which developed bedding-parallel shears, detachments, NW–SE axis folding, and thrusting north-eastwards. The underthrusting effects were localized and transient, ceasing as the strike-slip fault incised upwards through the Chalk. Subsequent flexuring, on ENE–WSW axes, curved foreshore bedding and enhanced closures of the earlier non-cylindroidal folding, producing domes and basins, sporadically exposed in the foreshore. Here, they have been downfaulted in a graben that is tilted, with downthrow increasing southward (seaward) towards the Langtoft Fault. Folding and faulting at Selwicks Bay, 4 km ENE, has been related to four deformation phases (‘D1–D4’). D1 produced gentle NNW–SSE folds and north-eastward shearing on bedding planes, comparable with the Dykes End cliff structures, and sinistral strike-slip movement on ESE–WNW faults, parallel to the Langtoft Fault. D2 was a tensional period. D3 produced E–W folds, comparable with the Dykes End cross-flexures, and D4 comprised extensional phases, comparable with the Dykes End faulting and graben development.

Structural evolution of Bondoc–Burias area (South Luzon, Philippines) from seismic data

Recently acquired 2-D seismic profiles in the offshore area between Bondoc Peninsula and Burias Island, South Luzon, Philippines, are interpreted in the context of known structural styles observed onshore and in relation to paleo- and neo-tectonic regimes in the region. Two distinct seismic sequences can be distinguished relative to their structural style and tectonic significance. The top of a lower sequence shows strongly reflective properties. This unit, correlative to Late Oligocene to Early Miocene limestone bodies observed onshore in Bondoc Peninsula and Burias Island, is affected by intense to moderate superposed folding and thrust faulting. An upper sequence, correlative to a two-member turbiditic and shallower marine clastic deposit widely exposed in Bondoc Peninsula, is affected by thrust faulting and deformation associated with overturned tight folding. The onshore equivalents of these two seismic sequences form the core of a bent anticlinorium that twists from a NW–SE axis in onshore Bondoc into a N–S axis southwards into the southern tip of the peninsula, then back to a NW–SE axis in the offshore region further to the south. Overlying this structural core is a relatively less deformed sequence where syn-sedimentary half-grabens are still preserved in places. This complex structural style is the result of a series of several tectonic events occurring from the Eocene to the Present, involving carbonate build-up, deep water turbidite deposition, consequent compression (folding and faulting), and late-event half graben-controlled deposition. Some resulting structures are indicative of tectonic inversion processes (positive and negative) which may prove to be potentially favorable in the search for structural plays in the area.

Synkinematic emplacement of Lassiter Coast Intrusive Suite plutons during the Palmer Land Event: evidence for mid-Cretaceous sinistral transpression at the Beaumont Glacier in eastern Palmer Land

New structural and geochronological data from the Eastern Palmer Land Shear Zone, in the vicinity of Beaumont Glacier, provide the first evidence of dated structural control on emplacement of the 119–95 Ma, >13000 km 2 Cretaceous Lassiter Coast Intrusive Suite, during the accretionary mid-Cretaceous Palmer Land Event orogeny. A previously undated >100 m thick dyke-like quartz tonalite intrusion was emplaced at 116.5 ± 1.5 Ma (Ar–Ar biotite cooling age) along a NW–SE axis, coeval with NW–SE compressional deformation, and possibly controlled by sinistral transpression along the Beaumont Glacier shear zone. The quartz tonalite preserves two styles of deformation and was probably progressively deformed by normal-sinistral shearing during magmatic cooling with initial deformation of mafic enclaves in the dyke interior and final formation of proto-mylonite to mylonite on the dyke margin. The quartz tonalite cuts folding associated with Phase 1 of the Palmer Land Event, indicating that this folding is older than 116 Ma, extending the onset of Phase 1 back in time. Mylonite on the quartz tonalite sheet margin was subsequently thermally reset at c . 107 Ma (Ar–Ar biotite method), during a peak in Lassiter Coast Intrusive Suite magmatism. Supplementary material: Country rock lithological data, petrographic description of tonalite and Ar–Ar geochronology data are available at www.geolsoc.org.uk/SUP18552 .

Magnetic fabrics of diamagnetic rocks and the strain field associated with the Dead Sea Fault, northern Israel

In order to exploit the potential of AMS axes ( k 1, k 2, k 3) and magnitudes as a tool to estimate the strain field around major faults, the AMS of calcite-bearing diamagnetic rocks that crop out next to the Dead Sea Fault (transform) (DSF) were measured. The calcite-bearing Bar Kokhba limestone contains magnetic fabrics due mainly to the diamagnetic phase, as indicated by the low iron content (<130 ppm), and strong negative susceptibilities of all the AMS principal axes. The magnetic fabrics are solely controlled by the alignment of c-axes of almost pure calcite crystals and help to assess the strain fields prevailing post-deposition and during the tectonic evolution of the DSF. Based on the AMS measurements of 146 diamagnetic samples as well as 65 paramagnetic samples, three groups of minimum k 3 AMS axes are defined: (1) ∼NNE-plunging axis; (2) ∼NW–SE axis; and (3) ∼E–W axis. The latter two groups of k 3 axes are aligned sub-parallel to Neogene to Pleistocene finite-strain axes inferred from meso-scale structures (i.e., folds, faults and veins) next to the DSF. This indicates that k 3 axes of diamagnetic rocks can be excellent proxies for strain field directions around major faults. Differences in the degree of anisotropy P′ (up to ∼2%) and in susceptibility difference Δ k (up to ∼0.2) of the diamagnetic rocks are related to differences in strain magnitudes. Based on the proximity of the studied outcrops to the fault traces, the values of these variables reflect the stored inelastic strain within the calcite matrix due to repeated faulting activity.

Distinguishing potential sources of arsenic released to groundwater around a fault zone containing a mine site

Arsenic (As) contamination in groundwater in mineralized areas typically results from the oxidation of As-rich sulfide minerals in aquifers, from hydrothermal alteration of geothermal systems, or as a result of anthropogenic influences such as mining activity. The primary goal of this study was to determine the spatial and temporal variance in As concentrations in shallow groundwater in a mineralized area and to identify the main As source controlling the concentration patterns. To this end, a combination of a geostatistical technique for space–time modeling of As concentrations and a numerical simulation, which models the transport of As in groundwater, is implemented. A study site in North Sulawesi, Sulawesi Island, Indonesia was selected as it was suitable for investigating the importance of fault lines and metal mining on As contamination. Initially, stable isotope analysis was used to ascertain the groundwater source and the mixing mechanism of the shallow and deep groundwater. Geostatistical modeling revealed consistent general patterns of As concentrations during the past 10 years, with high concentrations found along a NW–SE axis. By matching the geostatistical results with the distributions of As concentrations obtained through transport modeling, the deep-seated hydrothermal system along the fault zone was found to be the major As source. Wastewater from the mine was also observed to be a local As source. Another important influence on the As concentration pattern was a river, which acted as a boundary to separate the groundwater systems into two regions.

Kinematic model for Tenerife Island (Canary Islands, Spain): Geodynamic interpretation in the Nubian plate context

Establishment of a geodetic network in Tenerife is the starting point for the use of GPS and other precise geodetic techniques in the support of the study of kinematics and their relation with island volcanic activity. This paper is focused on the characterization of volcanotectonic activity of Tenerife, to determine the geodynamic framework for volcanic surveillance. TEGETEIDE network, set up in 2005 and re-observed each year, is composed of seven GNSS–GPS stations scattered throughout the island. A horizontal deformation model is presented in order to explain the observed island displacement pattern in the geodynamic context of the Nubian plate. According to the models obtained, the most important geologic structures, such as the volcanic rifts and the caldera, determine the current deformation pattern of Tenerife. The geodynamics of the most stable areas of the island behave similarly to that observed from the permanent GNSS–GPS reference stations located in La Palma and Gran Canaria Islands. Anomalous geodynamic behaviour has been detected in two zones of Tenerife, which configure an NW–SE axis crossing the central sector of the island, related with the volcanotectonic activity of the island and its surroundings.

TRACING THE BIPOLAR OUTFLOW FROM ORION SOURCE I

Using CARMA, we imaged the 87 GHz SiO v=0 J=2-1 line toward Orion-KL with 0.45 arcsec angular resolution. The maps indicate that radio source I drives a bipolar outflow into the surrounding molecular cloud along a NE--SW axis, in agreement with the model of Greenhill et al. (2004). The extended high velocity outflow from Orion-KL appears to be a continuation of this compact outflow. High velocity gas extends farthest along a NW--SE axis, suggesting that the outflow direction changes on time scales of a few hundred years.

Petrology of a non-classical Barrovian inverted metamorphic sequence from the western Arunachal Himalaya, India

In this study, we reconstruct the inverted metamorphic sequence in the western Arunachal Himalaya using combined structural and metamorphic analyses of rocks of the Lesser and Greater Himalayan Sequences. Four thrust-bounded stratigraphic units, which from the lower to higher structural heights are (a) the Gondwana rocks and relatively weakly deformed metasediments of the Bomdila Group, (b) the tectonically interleaved sequence of Bomdila gneiss and Bomdila Group, (c) the Dirang Formation and (d) the Se La Group are exposed along the transect, Jira–Rupa–Bomdila–Dirang–Se La Pass. The Main Central thrust, which coincides with intense strain localization and the first appearance of kyanite-grade partial melt is placed at the base of the Se La Group. Five metamorphic zones from garnet through kyanite, kyanite migmatite, kyanite-sillimanite migmatite to K-feldspar-kyanite-sillimanite migmatites are sequentially developed in the metamorphosed low-alumina pelites of Dirang and Se La Group, with increasing structural heights. Three phases of deformation, D 1–D 2–D 3 and two groups of planar structures, S 1 and S 2 are recognized, and S 2 is the most pervasive one. Mineral growths in all these zones are dominantly late-to post-D 2, excepting in some garnet-zone rocks, where syn-D 1 garnet growths are documented. Metamorphic isograds, which are aligned parallel to S 2 were subsequently folded during D 3. The deformation produced plane-non-cylindrical fold along NW–SE axis. In the garnet-zone, peak metamorphism is marked by garnet growth through the reaction biotite + plagioclase → garnet + muscovite. An even earlier phase of syn-D 1 garnet growth occurred in the chlorite stability field with or without epidote. In the kyanite-zone metapelites, kyanite appeared via the pressure-sensitive reaction, garnet + muscovite → kyanite + biotite + quartz. Staurolite was produced in the same rock by retrograde replacement of kyanite following the reaction, garnet + kyanite + H 2O → staurolite + quartz. These reactions depart from the classical kyanite- and staurolite-isograd reactions in low-alumina pelites, encountered in other segments of eastern Himalaya. In the metapelites, just above the kyanite-zone, melting begins in the kyanite field, through water-saturated and water-undersaturated melting of paragonite component in white mica. Leucosomes formed through these reactions are characteristically free of K-feldspar, with sodic plagioclase and quartz as the dominant constituents. With increasing structural height, the melting shifts to water-undersaturated melting of muscovite component of white mica, producing an early K-feldspar + kyanite and later K-feldspar + sillimanite assemblages and granitic leucosomes. Applications of conventional geothermobarometry and average P– T method reveal near isobaric (at P ∼ 8 kbar) increase in peak metamorphic temperatures from 550 °C in the garnet-zone to >700 °C for K-feldspar-kyanite-sillimanite-zone rocks. The findings of near isobaric metamorphic field gradient and by the reconstruction of the reaction history, reveal that the described inverted metamorphic sequence in the western Arunachal Himalaya, deviates from the classical Barrovian-type metamorphism. The tectonic implication of such a metamorphic evolution is discussed.

A New Mid-Infrared Map of the BN/KL Region Using the Keck Telescope

We present a new mid-infrared (12.5micron) map of the BN/KL high-mass star-forming complex in Orion using the LWS instrument at Keck I. Despite poor weather we achieved nearly diffraction-limited images (FWHM = 0.38'') over a roughly 25'' X 25'' region centered on IRc2 down to a flux limit of ~250 mJy. Many of the known infrared (IR) sources in the region break up into smaller sub-components. We have also detected 6 new mid-IR sources. Nearly all of the sources are resolved in our mosaic. The near-IR source ''n'' is slightly elongated in the mid-IR along a NW--SE axis and perfectly bisects the double-peaked radio source ''L''. Source n has been identified as a candidate for powering the large IR luminosity of the BN/KL region (L = 10^5 L_sun). We postulate that the 12 micron emission arises in a circumstellar disk surrounding source n. The morphology of the mid-IR emission and the Orion ''hot core'' (as seen in NH_3 emission), along with the location of water and OH masers, is very suggestive of a bipolar cavity centered on source n and aligned with the rotation axis of the hypothetical circumstellar disk. IRc2, once thought to be the dominant energy source for the BN/KL region, clearly breaks into 4 sub-sources in our mosaic, as seen previously at 3.8 -- 5.0 micron. The anti-correlation of mid-IR emission and NH_3 emission from the nearby hot core indicates that the IRc2 sources are roughly coincident (or behind) the dense hot core. The nature of IRc2 is not clear: neither self-luminous sources (embedded protostars) nor external heating by source I can be definitively ruled out. We also report the discovery of a new arc-like feature SW of the BN object, and some curious morphology surrounding near-IR source ''t".

Cp2Ti(dddse): a well known precursor for Se-containing donors

Bis(η5-cyclo­penta­dienyl)[5,6-di­hydro-1,4-dithiine-2,3-di­selen­o­lato(2−)-κ2Se,Se′]­titanium(IV), [Ti(C5H5)2(C4H4S2Se2)], is isostructural with the all-sulfur derivative Cp2Ti(dddt) [Guyon et al. (1994). Bull. Soc. Chim. Fr. 131, 217–226] (dddt2− = 5,6-di­hydro-1,4-dithiine-2,3-di­thiol­ate). There are two molecules in the asymmetric unit, and one ethyl­ene group of the dddse2− ligand is found to be disordered in one of them. As in Cp2Ti(dddt), the TiSe2C2 ring is folded along the Se⋯Se axis by 49.75 (3) and 53.29 (3)° in the two independent molecules.

Late amagmatic extension along the central and eastern segments of the West Philippine Basin fossil spreading axis

The spreading processes within the West Philippine Basin (WPB) remain partly unknown. This study presents an analysis of the tectono-magmatic processes that happened along its spreading axis during the conclusion of the last spreading phase at 33/30 Ma. We demonstrate that the late episode of N–S opening from an E–W-trending spreading system has been followed by a late tectonic event occurring in the central and eastern parts of the basin. This event was responsible for transtensional strain accommodated along the NW–SE faults cutting through the former E–W rift valley in the central part of the basin. In its eastern part, the same event occurred at a larger extent and led to the creation of a new NW–SE axis, obliquely cutting the older E–W spreading segments and their associated spreading fabrics. At this location, several tens of kilometers of slightly oblique amagmatic extension occurred following a ∼60° direction. We propose that this late event is associated with the onset of E–W opening of the Parece-Vela Basin located along the eastern border of the WPB at 30 Ma. Extensive stresses within this basin were probably transmitted to the hot and easily deformable rift zone of the WPB. The newly-created NW–SE axis most likely propagated from east to west, being responsible for scissors opening within the WPB. NE–SW extension ceased when well-organized spreading started at 26 Ma in Parece-Vela Basin, accommodating entirely the global extensive stress pattern.

Facies and Fracture Architecture of the Tensleep Sandstone, Bighorn Basin, Wyoming: Preiiminary Result of an Outcrop and Subsurface Study: ABSTRACT

The Middle Pennsylvanian to Lower Permian Tensleep Sandstone has been the most prolific producer in the state of Wyoming. Now in its advanced stages of production. it is critical to accurately characterize the Tensleep facies and fracture architecture. Two outcrop locations have been selected: Alkali Creek has cross-strata dip parallel exposures at close spacings for eolian facies architecture Ziesman Dome is an NW-SE trending asymmetric anticlinal closure with the SE axis having a marked dextral dislocation, and is selected for analysis of fracture architecture. Byron Field is also an anticlinal closure with NW-SE trend which is selected for location of subsurface study. Methods of study for outcrop includes high- precision electronic surveying, photomosaics, geologic mapping, and fracture spacing and orientation measurements. The subsurface study includes conventional wireline logs, cores, and porosity and permeability data. In addition, a microresistivity log was evaluated from the Lindsay 3H horizontal well. Tensleep facies architecture is defined by a hierarchy of elements. Parasequences are made up of marine to marginal marine dolomitic sandstones and sandy dolostones (<10[sup -2] to 10[sup 2] md) in the lower 20-50%, and eolian dune, interdune and large-scale deformed sandstones in the upper part. Eolian dune sandstones, the primary reservoir (2more » to 3x10[sup 2] md), am characterized by very large-scale (up to 40 ft thick) tabular-planar cross strata with lower permeability wind ripple strata (1 to 2x10[sup 2] md, strongly anisotropic) concentrated above 1st- and 2nd-order bounding surfaces. Medium-scale trough cross stratified intrasets are common; however, their spatial dimensions and distribution pattern are uncertain at this time.« less

The structure of the Skye lava field

Synopsis A new map and interpretation of the structure of the Skye lava field and its offshore continuation are presented. Onshore the base of the lavas is synclinal with a NW–SE axis resulting from loading-induced subsidence. The development of later N–S- to NE–SW-trending folds, including the offshore Canna Basin, is consistent with movement, during the Oligocene, on N–S- to NE–SW-trending faults controlling the structure of the Sea of the Hebrides Basin. Deposition of Oligocene sediments within the Canna Basin resulted in burial of potential hydrocarbon source rocks to depths of c. 2.3 km.

Interpretation of magnetic anomalies over the Blackstones Bank Igneous Centre, West Scottish Shelf

A 32 × 32 km2 region of the B. G. S. one inch aeromagnetic anomaly map over the Blackstones Bank igneous centre was digitized at 1 km intervals and transformed into pseudogravimetric anomalies. A three dimensional model was obtained for the subsurface structure of the Blackstones Bank igneous centre by interpreting the pseudogravimetric anomaly. The main body of the model extends to a depth of 15 km with a reverse magnetization of 0.93 A m−1. A shallow normally magnetized body occurs within this to depths of 1.0–5.0 km with a magnetization in the range 0–2.47 A m−1. Bullerwell (1963) recognized the similarity between aeromagnetic anomalies over the Blackstones Bank situated about 50 km SW of Mull and over the known Tertiary igneous centres such as Mull, Skye and Rhum. This similarity led him to propose the existence of a Tertiary igneous centre related to the Islay and Jura dyke swarms at the Blackstones Bank. Geophysical and geological investigations have been carried out by several workers on the Blackstones Bank and their results have confirmed Bullerwell's suggestion (McQuillin and Binns 1975). This note presents an interpretation of aeromagnetic anomalies over the Blackstones Bank igneous centre (Fig. 1). The almost circular nature of the anomaly is distorted by its elongation along the NW–SE axis. The magnetic anomaly over the Blackstones Bank is dominantly negative with a relatively narrow positive anomaly superimposed. This indicates the presence of a reversely magnetized body possibly with a normally magnetized core. The complicated nature . . .