Minor Deformation Research Articles

Seismic performance of a building affected by moderate liquefaction during the Christchurch earthquake

The seismic performance of an important structure in Christchurch, New Zealand was well-documented during the 2010–2011 Canterbury earthquake sequence. Minor ground deformation and negligible-to-minor structural damage occurred during the primary events of the sequence, except for the 22 February 2011Mw6.2 Christchurch earthquake, which produced differential movement of the basement mat and architectural and structural damage. This case history is evaluated to garner insights. Static settlements are estimated to establish the pre-seismic conditions of the building. Dynamic nonlinear effective stress soil-structure-interaction analysis are performed for the primary events of the Canterbury earthquake sequence using FLAC2D with the PM4Sand constitutive model to capture the cyclic response of the key soil units. The analytical results indicate the post-Canterbury earthquake sequence measured differential mat movements were primarily due to the earthquake events. A thin liquefiable layer, which historic maps indicate is now a buried stream deposit, is largely responsible for the ground movements. A medium dense sandy gravel also appeared to contribute significantly to the observed foundation movements.

Lower limit law of welding windows for explosive welding of dissimilar metals

The influence of explosive charge thickness on the quality of explosive welding of dissimilar metals was investigated. The lower limit law should be followed in the course of explosive welding. Three welding experiments of stainless steel (410S) and steel (Q345R) were carried out in three different kinds of explosive charge thicknesses, namely 15, 25 and 35 mm. Interfaces of morphology and mechanical properties of three samples were observed and tested. It was found that micro and small wavy bonding is mainly formed for charge thickness of 15 mm whose strength is the highest with minor deformation and few defects in the interface; small and middle wavy bonding are mainly formed for charge thickness of 25 mm whose strength is comparatively mediocre; big wavy bonding is mainly formed for charge thickness of 35 mm whose strength is the lowest. The cause of high bonding strength of the micro and small wavy interface was analyzed and verified on the basis of the results of Electron Probe Micro-Analyzer (EPMA) tests of three selected samples.

Monitoring the behavior of segment joints in a shield tunnel using distributed fiber optic sensors

Summary Shield tunneling is a popular tunnel construction technique for its efficiency and speed. However, uncertainties associated with site soil conditions, past loading histories and analytical modeling, can result in performance issues. To monitor shield tunnels and ensure performance and safety, fiber optic sensing technique is proposed. Based on Brillouin optical frequency domain analysis, the technique can monitor the opening and closing of segmental joints in shield tunnels with high sensitivity. To determine tunnel lining segment displacement, different fixed-point spacings have been tested in the lab. The test results show that the difference in fixed-point distances had no impact on the test accuracy and the sensing cable with 0.9-mm polyurethane sheath coater has the best performance. For demonstration, the Brillouin optical frequency domain analysis-based monitoring technique is applied to the Suzhou Metro Line 1 tunnel for tunnel lining segment joint monitoring. The technique detected minor deformation of the segment joints in tunnels in operation and located leakages within the tunnel. The technique further identified that the minor deformations of the segment joints and track bed expansion were closely associated with temperature variations.

Three-dimensional numerical investigation and modeling of binary alumina droplet collisions

The off-center collision of binary equal-sized alumina droplets has been investigated by employing a three-dimensional direct numerical simulation method which involves the volume of fluid (VOF) and adaptive mesh refinement method. The simulations of tetradecane droplet collision are carried out to validate the numerical method. The results show good agreement with experiments. The off-center collisions of alumina droplet with diameter 10μm are numerically investigated at various Weber numbers (30–400) and impact numbers (0.1–0.7). The Ohnesorge number is 0.1151. Four collision outcomes are obtained, coalescence after substantial deformation, reflexive separation, coalescence after long extension, and stretching separation, respectively. Bouncing is achieved by employing the double VOF functions method. In addition, as to the collision at various impact parameters, the critical Weber number of separation is obtained. And the collision regimes of alumina droplet are mapped out. Furthermore, alumina droplet collisions are modeled with the consideration of viscous dissipation, including the model of coalescence after minor deformation, bouncing model, reflexive separation model, stretching separation model, as well as the model for calculating the droplet parameters after separation. Bouncing model, reflexive separation model and stretching separation model are in good agreement with the present numerical results.

Mechanical Characterization of Individual Brewing Yeast Cells Using Microelectromechanical Systems (MEMS): Cell Rupture Force and Stiffness

The mechanical properties of individual yeast cells were measured using microelectromechanical systems (MEMS). Samples were taken throughout two controlled fermentations conducted as per ASBC Yeast-14: one utilized ale yeast (Saccharomyces cerevisiae, “red ale”) and the other utilized a lager strain (S. pastorianus, “SMA”). At least five lager and five ale cells were tested at each fermentation phase (start, middle, and end). Cell compression was induced by a MEMS squeezer, and displacement measurements were taken using optical microphotographs. The failure of each cell was similar; the cell would undergo minor deformation until visible rupture occurred, followed by significant cell shrinkage. Across all fermentation phases ale cells ruptured under an average force of 0.28 ± 0.05 μN, whereas lager cells ruptured at 0.47 ± 0.10 μN. The average stiffness at the midpoint of fermentation was found to be 4.8 ± 1.0 and 5.3 ± 0.9 μN/μm for ale and lager cells, respectively. The use of MEMS technology to study physical characteristics of brewing yeast during fermentation has not previously been attempted (to the authors' knowledge). This study may assist brewers in the selection of process parameters to improve yeast health and in the design of novel yeast handling technologies.

The deforming Nazca slab in the mantle transition zone and lower mantle: Constraints from teleseismic tomography on the deeply subducted slab between 6°S and 32°S

We present new tomographic models of the Nazca slab under South America from 6°S to 32°S, and from 95 km to lower mantle (895 km) depths. By combining data from 14 separate networks in the central Andes, we use finite-frequency teleseismic P-wave tomography to image the Nazca slab from the upper mantle into the mantle transition zone (MTZ) and the uppermost lower mantle on a regional scale. Our tomography shows that there is significant along-strike variation in the morphology of the Nazca slab in the MTZ and the lower mantle. Thickening of the slab in the MTZ is observed north of the Bolivian orocline, possibly related to buckling or folding of the slab in response to the penetration of a near-vertical slab into the higher-viscosity lower mantle, which decreases the sinking velocity of the slab. South of the orocline, the slab continues into the lower mantle with only minor deformation in the MTZ. In the lower mantle, a similar difference in morphology is observed. North of 16°S, the slab anomaly in the lower mantle is more coherent and penetrates more steeply into the lower mantle. To the south, the slab dip appears to be decreasing just below the 660 km discontinuity. This change in slab morphology in the MTZ and lower mantle appears to correspond to the change in the dip of the slab as it enters the MTZ, from steeply dipping in the north to more moderately dipping in the south.

Afontova Gora II archaeological site: Geology and postdepositional deformation (Krasnoyarsk, Siberia)

The Afontova Gora II archaeological site located within two geologically and geomorphically different areas has been studied in terms of geology and Quaternary deposition history. Both areas lie upon alluvial terrace II of the Yensei River. At the time when terrace I alluvium was deposited, aeolian and slope-wash facies accumulated on the surface of terrace II and a slope-wash apron formed on the gently sloping surface of terrace III. It is at these different levels of the Yenisei River bank that the latest Paleolithic Afontov culture of Siberia has been found. At the Late Glacial-Holocene boundary, the slope-wash apron upon terrace III was involved in landsliding and thrust over terrace II, which deformed the subaerial deposits over both terraces II and III. As shown by detailed analysis, the landslide deposits are either strongly deformed to the degree of losing of their primary sedimentary textures and structures or form imbricated blocks with deformed margins but minor deformation in their interior. The preserved textures and structures of sediments inside the imbricated landslide blocks provide stratigraphic and genetic constraints and prove the in situ origin of anthropological, archaeological, and paleontological finds. This division also explains the archaeological sterility and abnormal thickness of the subaerial cover upon the landslide blocks.

Facies analysis and its relation to point-sourced growth faults in river-dominated prodeltaic delta front deposits of the Cretaceous Ferron Notom Delta, Utah, USA

This study evaluates the evolution of a small-scale growth fault within a deltaic parasequence of the Ferron Sandstone, Utah. Analysis is based on 4 stratigraphic logs, and a panorama covering 100 m of lateral exposure.Five growth-fault blocks are displayed in strike and dip views. The listric faults dip basinward, and sole out into bedding parallel decollement surfaces associated with deformed prodelta shales, which also form diapirs. Throw on individual faults averages 4 m and heave increases with depth from ∼2.5 to ∼5 m. Strikes on fault planes average 160°, and fault dip decreases with depth from 50° to 0°, where they become parallel to bedding.Pre-growth facies comprise heterolithics with abundant graded beds, current-ripples, wave-ripples, small-scale soft sediment deformation, and a low bioturbation index. This indicates deposition in a river-dominated, storm-influenced delta that was supplied primarily by storm-triggered flood events and prograded rapidly. Growth strata are primarily planar and quasi-planar fine sandstones deposited as upstream and downstream accreting mouth bars.Faulting initiates with the building of a “critical load” reflecting a low-angle delta front foreset, probably linked to deposition in a mouth bar. Mobile prodelta muds form diapirs that breached the sediment-water interface, providing accommodation for the fault blocks. Termination of faulting occurred when sandy growth strata contacted and locked into higher strength pre-growth heterolithics deeper in the section. Minor deformation of growth strata is demonstrated by synthetic microfaulting in growth sands.This study emphasizes a localized stress field (i.e., point sourced) associated with sandy mouth bar deposits, which acted as fault initiation points. This contrasts with the distributed stress regimes commonly associated with regional-scale growth faults along continental margins. This can lead to expanded, but localized, reservoir compartments within river-dominated deltaic systems, especially those in epeiric seas or other shallow-water sedimentary basins, such as Prudhoe Bay Field, Alaska.

Structural setting for Canadian Malartic style of gold mineralization in the Pontiac Subprovince, south of the Cadillac Larder Lake Deformation Zone, Québec, Canada

The structural setting of the Pontiac Subprovince in the vicinity of the world-class Canadian Malartic gold deposit has been revisited by combining and reinterpreting airborne geophysical surveys together with a century of structural observations. Felsic-intermediate intrusive bodies are a key component of this deposit. Defining the regional and local favorable structural setting for intrusive rock emplacement within the clastic meta-sedimentary rocks of the Pontiac Group, south of the Cadillac Larder Lake Deformation Zone, may further assist gold exploration in similar tectonic environment.Three structural domains are interpreted in the area based on the geometry of the bedding, folds and structural fabrics related to the three major phases of deformation. During these events four phases of magmatism and one metamorphic episode occurred. The North domain, which hosts the Canadian Malartic deposit, is characterized by highly variable bedding orientations produced by the interference patterns of isoclinal F1 folds overprinted by open to tight, steeply dipping, F2 folds. The bedding in this domain is cut by a penetrative S2 biotite foliation, which possibly built on rheological changes enhanced by metasomatism in the footprint of the Canadian Malartic deposit. By contrast, the Central and South domains display homogeneous bedding orientations cross-cut by a discrete S2 biotite foliation and syn- to late- D2 metamorphic porphyroblasts. In all domains the L2 stretching lineation consistently plunges at about 60 degrees toward the east. D3 is a minor deformation event in the Pontiac Subprovince, which possibly correlates with late dextral transcurrent movement along the Cadillac Larder Lake Deformation Zone.Intrusive bodies were emplaced throughout the first and second deformation events. Phase 1 monzonite, quartz-monzodiorite and granodiorite plutons (ca. 2683–2680Ma) intruded into consolidated Pontiac sedimentary rocks during D1. Phase 2 quartz-monzodiorite bodies (ca. 2679–2676Ma) predominantly formed in the North Domain along F1 fold axial surfaces prior to or at the onset of D2. Phase 3 basic dykes (ca. 2675–2673Ma) cross-cut earlier felsic-intermediate intrusions across all domains and subsequently developed an S2 metamorphic hornblende foliation. Phase 4 magmatism (ca. 2672–2662Ma) is related to the Décelles Batholith S-type granite and pegmatite, which is interpreted to be contemporaneous with the peak of regional metamorphism. The Décelles Batholith may project at depth underneath the Canadian Malartic deposit and could be associated with magmatic-hydrothermal mineralizing fluids in the Canadian Malartic deposit.Gold mineralization at Canadian Malartic is spatially located on the contact of Phase 2 quartz-monzodiorite bodies. The proximity to the Cadillac Larder Lake Deformation Zone combined with the rheological contrast between steeply dipping clastic meta-sedimentary rocks and quartz-monzodiorite intrusions favored the protracted failure of the contacts between these two rock masses, thus forming favorable conduits for hydrothermal fluids (e.g., the Sladen Fault Zone). Such specific rheological behavior is demonstrated by domains of structural complexity, emphasized by the variance of the bedding dip. These structurally complex zones systematically host gold mineralization in the Canadian Malartic district of the Pontiac Subprovince proximal to the Cadillac Larder Lake Deformation Zone.

Structural pattern and emplacement mechanism of the Neka Valley nappe complex, eastern Alborz, Iran

The Neka Valley nappe complex is exposed in the south of Gorgan County in the eastern Alborz fold-and-thrust belt. We use the results of a regional survey of the structural data and their patterns to interpret the mechanisms that emplaced the unmetamorphosed nappes in the foreland fold-and-thrust belt of the Alborz Mountains. Most of the strain magnitudes are low in the study area but increase slightly towards what are probably their proximal ends. Strain ellipsoid is dominantly oblate with XY aligned along and across the belt (or the nappe complex). The average kinematic vorticity number, W k = 0.6 which indicates most of the strain partitioning resulted in a general shear. Most of Flinn’s k values and α (the stretch along the shear plane) values are lower than 1. Structural indicators such as orthogonal extensional joints, pinch-and-swell structures, anastomosing cleavages, and listric normal and growth faults developed by push from the rear. Large-scale thrust complexes with opposed-dips such as triangle zones (as well as k and α-values <1) are compatible with the shear flow diverging distally and streamlines expected of the rear compression emplacement mechanism. Together with a later minor brittle deformation, these major ductile strains appears to provide a general model suitable for the emplacement of the nappes studied in a thin-skinned fold-and-thrust belt where the sedimentary cover strata shortened and imbricated in the upper crust.

Juvenile magma recognition and eruptive dynamics inferred from the analysis of ash time series: The 2015 reawakening of Cotopaxi volcano

Forecasting future activity and performing hazard assessments during the reactivation of volcanoes remain great challenges for the volcanological community. On August 14, 2015 Cotopaxi volcano erupted for the first time in 73years after approximately four months of precursory activity, which included an increase in seismicity, gas emissions, and minor ground deformation. Here we discuss the use of near real-time petrological monitoring of ash samples as a complementary aid to geophysical monitoring, in order to infer eruption dynamics and evaluate possible future eruptive activity at Cotopaxi. Twenty ash samples were collected between August 14 and November 23, 2015 from a monitoring site on the west flank of the volcano. These samples contain a range of grain types that we classified as: hydrothermal/altered, lithic, juvenile, and free crystals. The relative proportions of theses grains evolved as the eruption progressed, with increasing amounts of juvenile material and a decrease in hydrothermally altered material. In samples from the initial explosion, juvenile grains are glassy, microlite-poor and contain hydrothermal minerals (opal and alunite). The rising magma came in contact with the hydrothermal system under confinement, causing hydro-magmatic explosions that cleared the upper part of the plumbing system. Subsequently, the magmatic column produced a thermal aureole in the conduit and dried out the hydrothermal system, allowing for dry eruptions. Magma ascent rates were low enough to allow for efficient outgassing and microlite growth. Constant supply of magma from below caused quasi-continuous disruption of the uppermost magma volume through a combination of shear-deformation and gas expansion. The combination of increasing crystallinity of juvenile grains, and high measured SO2 flux indicate decreasing integrated magma ascent rates and clearing of the hydrothermal system along transport pathways in a system open to gas loss. The near real-time monitoring of ash samples combined with traditional geophysical monitoring techniques during the reawakening of Cotopaxi allowed us to gain a much clearer understanding of events than when using traditional geophysical monitoring alone.

Strengthening-toughening mechanism study of powder metallurgy Ti-Si alloy by interrupted in-situ tensile tests

Strengthening-toughening mechanism of powder metallurgy Ti-Si alloy was investigated by interrupted in-situ tensile tests. The fabricated Ti-Si alloy was strong and ductile. Slip band was blocked mainly by solutes and grain boundaries. Narrow deformed strips, aligned low angle grain boundaries and twin boundaries also played a positive role in this blockage. Cross-slip in the strain hardening stage lowered the difference value of ultimate tensile and yielding strength. Two-stage toughening mechanism was studied (necking onset was demarcation point). In the homogeneous deformation period before necking, strain compatibility was improved by the intergranular rotation (rotation axis along [0001], [-1100] and [-1102]), high-angle intragranular rotation, intergranular sliding and minor twinning deformation. In the heterogeneous deformation period after necking, microcracks initiation/coalescence was dragged by uniform stress distribution. Cracks propagation was also suppressed by dense grain boundaries and front plastic grains. The present comprehensive analysis of strength and toughness provided an in-depth understanding about the relationship among the processing, mechanical properties and microstructure of Ti alloy.

The Xitieshan volcanic sediment-hosted massive sulfide deposit, North Qaidam, China: Geology, structural deformation and geochronology

The Xitieshan deposit (~64Mt at 4.86% Zn, 4.16% Pb, 58g/t Ag, and 0.68g/t Au) is hosted by the Middle to Late Ordovician Tanjianshan Group of the North Qaidam tectonic metallogenic belt, NW China. This belt is characterized by island arc volcanic, ultra-high pressure (UHP) metamorphic and ophiolitic rocks. The Tanjianshan Group constitutes a succession of metamorphosed bimodal volcanic and sedimentary rocks, which are interpreted to have formed on the margin of a back-arc ocean basin between the Qaidam block and the Qilian block.Four stratigraphic units are identified within the Ordovician Tanjianshan Group. From northeast to southwest they are: 1) unit a, or the lower volcanic-sedimentary rocks, comprising bimodal volcanic rocks (unit a-1) and sedimentary rocks (unit a-2) ranging from carbonates to black carbonaceous schist; 2) unit b, or intermediate-mafic volcaniclastic rocks, characterized by intermediate to mafic volcaniclastic rocks intercalated with lamellar carbonaceous schist and minor marble lenses; 3) unit c, a purplish red sandy conglomerate that unconformably overlies unit b, representing the product of the foreland basin sedimentation during the Early Silurian; 4) unit d, or mafic volcanic rocks, from base to up, comprising the lower mafic volcaniclastic rocks (unit d-1), middle clastic sedimentary rocks (unit d-2), upper mafic volcaniclastic rocks (unit d-3), and uppermost mafic volcanic rocks (unit d-4). Unit a-2 hosts most of the massive sulfides whereas unit b contains subordinate amounts.The massive stratiform lenses constitute most of the Xitieshan deposit with significant amount of semi-massive and irregularly-shaped sulfides and minor amounts in stringer veins. Pyrite, galena and sphalerite are the dominant sulfide minerals, with subordinate pyrrhotite and chalcopyrite. Quartz is a dominant gangue mineral. Sericite, quartz, chlorite, and carbonate alteration of host rocks accompanies the mineralization.U-Pb zircon geochronology yields three ages of 454Ma, 452Ma and 451Ma for the footwall felsic volcanic rocks in unit a-1, sedimentary host rocks in unit a-2 and hanging-wall unit b, respectively. The Xitieshan deposit is considered to be coeval with the sedimentation of unit a-2 and unit b of the Tanjianshan Group. The Xitieshan deposit has been intensely deformed during two phases (main ductile shear and minor ductile-brittle deformation). The main ductile shear deformation controls the general strike of the ore zones, whereas minor deformation controls the internal geometry of the ore bodies. 40Ar-39Ar age of muscovite from mylonitized granitic gneisses in the ductile shear zone is ~399Ma, which is interpreted to date the Xitieshan ductile shear zone, suggesting that Early Devonian metamorphism and deformation post-dated the Tanjianshan Group.The Xitieshan deposit has many features similar to that of the Bathurst district of Canada, the Iberian Pyrite Belt of Spain, the Wolverine volcanogenic massive sulfide deposit in Canada. Based on its tectonic setting, host-rock types, local geologic setting, metal grades, geochronology, temperatures and salinities of mineralizing fluid and source of sulfur, the Xitieshan deposit has features similar to sedimentary exhalative (SEDEX) and VMS deposits and is similar to volcanic and sediment-hosted massive sulfide (VSHMS) deposits.

Shallow geophysical imaging of the Olympia anomaly: An enigmatic structure in the southern Puget Lowland, Washington State

Gravity and magnetic anomalies suggest that the Olympia structure beneath the southern Puget Lowland (western Washington State, U.S.) vertically displaces Eocene Crescent Formation strata. Northeast of the Olympia structure, middle Eocene Crescent Formation is beneath 4–6 km of Paleogene–Neogene and Quaternary strata of the Tacoma basin, whereas the Crescent Formation is exposed at the surface immediately to the south. Although numerous marine seismic reflection profiles have been acquired near the surface location of the Olympia structure as defined by potential field anomalies, its tectonic character remains enigmatic, in part because inlets of southern Puget Sound are too shallow for the collection of deep-penetration marine seismic profiles across the geophysical anomalies. To supplement existing shallow-marine data near the structure, we acquired 14.6 km of land-based seismic reflection data along a profile that extends from Crescent Formation exposed in the Black Hills northward across the projected surface location of the Olympia structure. The reflection seismic data image the Crescent bedrock surface to ∼1 km depth beneath the southern Tacoma basin and reveal the dip on this surface to be no greater than ∼10°. Although regional potential field data show a strong linear trend for the Olympia structure that implies folding over a blind thrust and/or bedrock juxtaposed against a weakly to nonmagnetic sediment section, high-resolution magnetic anomaly analysis along the land-based profile suggests that the structure is more complex. Overall, seismic and potential-field profiles presented in this study identify only minor shallow faulting within the projected surface location of the Olympia structure. We suggest that the mapped trace of the Olympia structure along the northern flank of the Black Hills, at least within the study area, is constrained by juxtaposed normal and reversely magnetized Crescent Formation units and minor tectonic deformation of Crescent Formation bedrock.

Preliminary In Vitro Study on O-Ring Wear in Mini-Implant-Retained Overdentures.

This preliminary in vitro study evaluated the simulated retention force of O-rings used for mini-implant overdenture treatment and the effect of mechanical fatigue corresponding to 6 months of wear. A mandibular overdenture analog device was attached to two mini-implants and underwent a tensile strength test before and after the application of insertion-removal and simulated masticatory cycles. Insertion-removal cycles led to a retention loss of 24%, whereas masticatory cycles did not influence retention. Micro-CT scans showed minor deformation following mechanical cycling, but the changes were milder than those observed in similar clinical specimens. Both experimental loading methods led to physical changes in the O-rings, which explains in part the similar clinically observed wear.

In-situ Electric Field-Induced Modulation of Photoluminescence in Pr-doped Ba0.85Ca0.15Ti0.90Zr0.10O3 Lead-Free Ceramics.

Luminescent materials with dynamic photoluminescence activity have aroused special interest because of their potential widespread applications. One proposed approach of directly and reversibly modulating the photoluminescence emissions is by means of introducing an external electric field in an in-situ and real-time way, which has only been focused on thin films. In this work, we demonstrate that real-time electric field-induced photoluminescence modulation can be realized in a bulk Ba0.85Ca0.15Ti0.90Zr0.10O3 ferroelectric ceramic doped with 0.2 mol% Pr3+, owing to its remarkable polarization reversal and phase evolution near the morphotropic phase boundary. Along with in-situ X-ray diffraction analysis, our results reveal that an applied electric field induces not only typical polarization switching and minor crystal deformation, but also tetragonal-to-rhombohedral phase transformation of the ceramic. The electric field-induced phase transformation is irreversible and engenders dominant effect on photoluminescence emissions as a result of an increase in structural symmetry. After it is completed in a few cycles of electric field, the photoluminescence emissions become governed mainly by the polarization switching, and thus vary reversibly with the modulating electric field. Our results open a promising avenue towards the realization of bulk ceramic-based tunable photoluminescence activity with high repeatability, flexible controllability, and environmental-friendly chemical process.

Effect of caffeine and retinoic acid on skeleton of mice embryos

The present study was conducted to evaluate the effect of caffeine and retinoic acid either separately or in combination on the skeleton of the developing embryos of mice. Pregnant females were treated with either caffeine or retinoic acid at the onset of organogenesis (7th day of gestation). At morphological level no abnormalities in either caffeine or retinoic acid in the developing embryos at 14th day of gestation whose mothers’ were administered caffeine (2mg/100g b.w.) or those of the mothers’ treated with retinoic acid up to 4mg/kg b.w. during the onset of the second trimester of pregnancy were observed. However, dose-dependent retinoic acid treatment initiates chondrocyte vacuolation, depression of PAS+ve intracellular inclusions and depression of nuclear fluorescence that were concomitant with downregulation of TGFβ2 expression in the perichondrium of the developing vertebrae. Co-administration of caffeine was found to ameliorate the effects of 2mg/kg b.w. rather than 4mg/kg b.w. of retinoic acid treatment. At the 18th day of gestation the uterine horns appeared normal without any signs of fetoresorption in all treatments. However, the effect of both caffeine (2mg/100g b.w) and retinoic acid at both doses (2, 4mg/kg b.w) in Alizarin Red stain of wholemount revealed minor phalange deformation of the developing limbs either separately or in combined treatments.

Room‐temperature dynamic quasi‐elastic mechanical behavior of a Zr–Cu–Fe–Al bulk metallic glass

The paper represents storage modulus and internal friction modulation upon cyclic loading of Zr61Cu27Fe2Al10 bulk metallic glassy samples within quasi‐reversible deformation regime. The structure of the samples was studied by X‐ray diffraction and transmission electron microscopy including high‐resolution imaging and selected‐area electron diffraction. It is found that kinetically frozen anelastic deformation accumulates on mechanical cycling at room temperature and causes an increase in the storage modulus and even nanocrystallization of a metallic glassy phase after a certain number of cycles. The study has shown that even a minor cyclic deformation in an elastic region can lead to the changes the atomic structure and in turn affect the elastic modulus.

Correcting peak deformation in Rosetta's ROSINA/DFMS mass spectrometer

The Double Focusing Mass Spectrometer (DFMS), part of the ROSINA instrument package aboard the European Space Agency's Rosetta spacecraft visiting comet 67P/Churyumov-Gerasimenko, experiences minor deformation of the mass peaks in the high resolution spectra acquired for m/Z=16, 17, and to a lesser extent 18. A numerical deconvolution technique has been developed with a twofold purpose. A first goal is to verify whether the most likely cause of the issue, a lack of stability of one of the electric potentials in the electrostatic analyser, can indeed be held responsible for it. The second goal is to correct for the deformation, in view of the important species located around these masses, and to allow a standard further treatment of the spectra in the automated DFMS data processing chain.

Petrology, geochemistry, and geochronology of mafic rocks from the Taoxinghu Devonian ophiolite, LongmuCo–Shuanghu–Lancang suture zone, northern Tibet: evidence for an intra-oceanic arc–basin system

A newly discovered Devonian ophiolite located in the Taoxinghu area of central Qiangtang on the Qinhai–Tibet Plateau is described. The ophiolite consists of gabbro and diabasic dikes, and invasive cumulate gabbros-leucogabbros. The ophiolite has undergone greenschist facies metamorphism and minor deformation. Dating of the metagabbro by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) zircon U–Pb techniques yielded a weighted mean age of 367.2 ± 3.3 Ma (Late Devonian). Whole-rock geochemical analyses show that the rocks belong to the tholeiite series, with weak depletion in light rare-earth elements (LREEs), almost no Eu anomalies, weak enrichment in large-ion lithophile elements (LILEs), depletion in Nb and Ta, and weak negative Hf and Ti anomalies. These characteristics are similar to those of back-arc basin basalts. Together, these characteristics suggest that the rocks of the Devonian ophiolite formed by ~30% partial melting of spinel lherzolite, which was enriched by interaction with aqueous fluids during the late-generation phases; there is no evidence of subduction-related melting. The Devonian ophiolite rocks in the Taoxinghu area were first discovered in the LongmuCo–Shuanghu–Lancang suture zone. Detailed geochemical analyses show that the rocks formed in a back-arc ocean basin environment, indicating that the LongmuCo–Shuanghu–Lancang suture zone in central Qiangtang represents a Late Devonian intra-oceanic subduction zone in the Palaeo–Tethys Ocean. The discovery of the central Qiangtang Devonian ophiolite provides essential data for understanding the evolutionary history of the Palaeo–Tethys Ocean, and for identifying and understanding the roles of the different tectonic units on the Qinghai–Tibet Plateau.