Experimental Study on Physical Similar Model of Fault Activation Law Based on Distributed Optical Fiber Monitoring

The impact ground pressure in coal mining is closely related to the fault structure, and the fault activation pattern is different when the working face advances along the upper and lower plates of the fault, respectively. In this paper, the F16 positive fault in the southern part of Yima coalfield is used as a prototype to carry out the physical similar model test simulating the process of the working face advancing from the upper and lower plates of the fault, and PPP-BOTDA optical fiber sensing technique is used to study the overburden deformation law and fault activation law when the working face is located in the upper and lower plates of the fault, respectively. The study shows that the key stratum breakage is closely related to the fault movement, and the shear stress concentration range occurs within the key stratum. The additional shear stress concentration at the fault surface caused by the working face advancing in the lower plate is much larger than that at the upper plate, which is the reason for the serious fault destabilization phenomenon at the lower plate. The upper rock layer on the fault face is affected by the mining action of the working face before the lower one, and the working face is affected by the fault in a larger range when advances in the lower plate than that in the upper plate, and the risk of fault activation instability occurs earlier when the working face advances in the lower plate than that in the upper plate. The distributed optical fiber sensing technology is used to verify the basic conclusions that the impact of the working face advancing from the lower plate is much greater than that from the upper plate, which is more likely to cause fault activation. The preferential placement of the working face in the upper plate in the fault area will be beneficial to mine pressure control. The results of the study provide an experimental basis for the application of distributed optical fiber sensing technology to the study of fault activation law.

Two-step obduction of the Porvenir serpentinites: A cryptic Devonian suture in SW Iberian Massif (Ossa-Morena Complex)

ABSTRACT The Porvenir serpentinites are an ∼600-m-thick body of meta-peridotites exposed in SW Iberia (Variscan Orogen). The serpentinites occur as a horse within a Carboniferous, out-of-sequence thrust system (Espiel thrust). This thrust juxtaposes the serpentinites and peri-Gondwanan strata onto younger peri-Gondwanan strata, with the serpentinites occupying an intermediate position. Reconstruction of the pre-Espiel thrust structure results in a vertical juxtaposition of terranes: Cambrian strata below, Porvenir serpentinites in the middle, and the strata at the footwall to the Espiel thrust culminating the tectonic pile. The reconstructed tectonic pile accounts for yet another major thrusting event, since a section of upper mantle (Porvenir serpentinites) was sandwiched between two tectonic slices of continental crust (a suture zone sensu lato). The primary lower plate to the suture is now overlying the upper plate due to the Espiel thrust. Lochkovian strata in the upper plate and the Devonian, NE-verging folds in the lower plate suggest SW-directed accretion of the lower plate during the Devonian, i.e., Laurussia-directed underthrusting for the closure of a Devonian intra-Gondwana basin. Obduction of the Porvenir serpentinites was a two-step process: one connected to the development of a Devonian suture zone, and another related to out-of-sequence thrusting that cut the suture zone and brought upward a tectonic slice of upper mantle rocks hosted in that suture. The primary Laurussia-dipping geometry inferred for this partially obducted suture zone fits the geometry, kinematics, and timing of the Late Devonian suture zone exposed in NW Iberia and may represent the continuation of such suture into SW Iberia.

Unsteady squeezing flow of Cu-Al2O3/water hybrid nanofluid in a horizontal channel with magnetic field

The proficiency of hybrid nanofluid from Cu-Al2O3/water formation as the heat transfer coolant is numerically analyzed using the powerful and user-friendly interface bvp4c in the Matlab software. For that purpose, the Cu-Al2O3/water nanofluid flow between two parallel plates is examined where the lower plate can be deformed while the upper plate moves towards/away from the lower plate. Other considerable factors are the wall mass suction/injection and the magnetic field that applied on the lower plate. The reduced ordinary (similarity) differential equations are solved using the bvp4c application. The validation of this novel model is conducted by comparing a few of numerical values for the reduced case of viscous fluid. The results imply the potency of this heat transfer fluid which can enhance the heat transfer performance for both upper and lower plates approximately by 7.10% and 4.11%, respectively. An increase of squeezing parameter deteriorates the heat transfer coefficient by 4.28% (upper) and 5.35% (lower), accordingly. The rise of suction strength inflates the heat transfer at the lower plate while the presence of the magnetic field shows a reverse result.

Influence of the Regime Parameters of Distillation on the Distribution of Volatile Components by Fractions in the Production of Cornel Distillate

На качество фруктовых дистиллятов оказывают существенное влияние различные физико-химические процессы, проходящие в дистилляционной установке под действием высокой температуры. В зависимости от особенностей биохимического состава для каждого вида сырья необходимо подбирать конкретные режимы дистилляции, обеспечивающие получение дистиллята с высокими органолептическими и физико-химическими характеристиками. В связи с этим цель работы состояла в исследовании влияния режимных параметров фракционированной дистилляции сброженной кизиловой мезги на распределение летучих компонентов по фракциям. В качестве объектов исследования в работе использовали фракции, полученные в процессе дистилляции сброженной кизиловой мезги на установке прямой сгонки «Kothe Distillationstechnik» (Германия). Экспериментально установлено, что повышение скорости при дистилляции сброженной кизиловой мезги приводит к увеличению объема отбираемой головной фракции, при одновременном снижении ее крепости. Показано, что изменение скорости дистилляции приводит к изменению характера перехода основных летучих компонентов в дистиллят и распределения их по фракциям. Изучена динамика перехода летучих компонентов в дистиллят при различных режимах работы дистилляционной установки - без задержки флегмы (обычный режим) и с задержкой флегмы на нижней тарелке укрепляющей колонны. Проведенные исследования показали, что при условии медленной дистилляции со скоростью не более 5,5 см3/мин в средние фракции переходит 82-85% компонентов энантового эфира, а содержание ацетальдегида снижается на 10-12% по сравнению с быстрой дистилляцией. Показано, что применение задержки флегмы на нижней тарелке укрепляющей колонны дистилляционной установки также способствует снижению перехода в кизиловый дистиллят ацетальдегида и этилацетата, и к сокращению потерь компонентов энантового эфира с головной и хвостовой фракциями. The quality of fruit distillates is significantly affected by various physical and chemical processes that take place in the distillation unit under the influence of high temperature. Depending on the characteristics of the biochemical composition for each type of raw material, it is necessary to select specific distillation modes that ensure the production of distillate with high organoleptic and physico-chemical characteristics. In this regard, the aim of the work was to study the influence of the regime parameters of fractionated distillation of fermented Cornel pulp on the distribution of volatile components by fractions. The fractions obtained during the distillation of fermented Cornel pulp at the direct distillation unit «Kothe Distillationstechnik» (Germany), were used as the objects of research. It is experimentally established that an increase in the speed during distillation of fermented Cornel pulp leads to an increase in the volume of the selected head fraction, while reducing its strength. It is shown that a change in the distillation rate leads to a change in the nature of the transition of the main volatile components to the distillate and their distribution by fractions. The dynamics of the transition of volatile components to distillate under different operating modes of the distillation unit - without phlegm delay (normal mode) and with phlegm delay on the lower plate of the reinforcing column is studied. Studies have shown that under the condition of slow distillation at a speed of no more than 5.5 cm3/min, 82-85% of the enantium ether components pass into the medium fractions, and the content of acetaldehyde decreases by 10-12% compared to fast distillation. It is shown that the use of phlegm delay on the lower plate of the strengthening column of the distillation unit also helps to reduce the transition to the Cornel distillate of acetaldehyde and ethyl acetate, and to reduce the loss of the components of the enantium ether with the head and tail fractions.

Lower plate extension of a retreating subduction zone: case study of the Sicily Channel Rift Zone

<p>The Alpine-Mediterranean belt is remarkable because of the strong arcuation of its subduction front and the abundance of extensional basins developed within an overall compressional setting. Both resulted from rapid slab rollback and trench retreat especially in Neogene time, accompanied by upper-plate extension and the opening of the Western Mediterranean basins. The Strait of Sicily is a very interesting geological area in the Western-Central Mediterranean, as it has undergone tectonic extension and opening of a rift zone (Sicily Channel Rift Zone, SCRZ) on the lower plate (Africa) of the subduction zone, marked by the Gela Front and the Calabrian Accretionary Wedge, located south and south-east of Sicily, respectively. Furthermore, the SCRZ is important for understanding and quantifying the independent motion and counter-clockwise rotation of the Adriatic plate in Neogene time (Le Breton et al. 2017). However, the exact timing, tectonic style and amount of deformation along the SCRZ remain unclear.</p><p>To tackle these questions, we re-evaluate multichannel seismic reflection profiles across the SCRZ (CROP seismic lines M24 and M25), as well as a series of seismic lines correlated with boreholes data from the VIDEPI project (www.videpi.com). Main stratigraphic horizons and tectonic structures are mapped in a 3D database using the MOVE Software (provided by Petex). Preliminary results indicate ~30 km of NE-SW extension through the Pantelleria Rift and onset of syn-rift deposition during the upper Messinian, which could be related with the fast slab retreat of the Calabrian Arc.</p><p> </p><p><strong>References:</strong></p><p>Le Breton E., M.R. Handy, G. Molli and K. Ustaszewski (2017)<strong>. </strong>Post-20 Ma motion of the Adriatic plate – new constrains from surrounding orogens and implications for crust-mantle decoupling, Tectonics, doi:10.1002/2016TC004443</p>

Rift inheritance controls the switch from thin- to thick-skinned thrusting and basal décollement re-localization at the subduction-to-collision transition

In accretionary convergent margins, the subduction interface is formed by a lower plate décollement above which sediments are scraped off and incorporated into the accretionary wedge. During subduction, the basal décollement is typically located within or at the base of the sedimentary pile. However, the transition to collision implies the accretion of the lower plate continental crust and deformation of its inherited rifted margin architecture. During this stage, the basal décollement may remain confined to shallow structural levels as during subduction or re-localize into the lower plate middle-lower crust. Modes and timing of such re-localization are still poorly understood. We present cases from the Zagros, Apennines, Oman, and Taiwan belts, all of which involve a former rifted margin and point to a marked influence of inherited rift-related structures on the décollement re-localization. A deep décollement level occurs in the outer sectors of all of these belts, i.e., in the zone involving the proximal domain of pre-orogenic rift systems. Older—and shallower—décollement levels are preserved in the upper and inner zones of the tectonic pile, which include the base of the sedimentary cover of the distal portions of the former rifted margins. We propose that thinning of the ductile middle crust in the necking domains during rifting, and its complete removal in the hyperextended domains, hampered the development of deep-seated décollements during the inception of shortening. Progressive orogenic involvement of the proximal rift domains, where the ductile middle crust was preserved upon rifting, favors its reactivation as a décollement in the frontal portion of the thrust system. Such décollement eventually links to the main subduction interface, favoring underplating and the upward motion of internal metamorphic units, leading to their final emplacement onto the previously developed tectonic stack.