ALBERT

Description: For the first time, one-pot solid-state synthesis of 12 photochromic materials based on photochromic dihydroindolizine system substituted in both fluorene part (region A) and the heterocyclic part (region C) has been established. This method has immense advantages, which are short-time reaction, high-yield and low-yield by-products, and easily purification and separation processes . In addition, this method will help in getting over the tremendously purification and low-yield problems faced since the worth-finding of this family of photochromic materials. The absorption maxima ( λ max ) and the half-lives ( t 1 / 2 ) of the colored betaines were detected in all cases using multichannel UV/Vis spectrophotometric measurements. The rate constants of the thermal back reaction of the betaines were determined at constant temperature by measuring the decrease in the maximum absorption intensity ( λ max ) with time. The half-lives ( t 1 / 2 ) and rate constants ( k ) of betaines under examination were calculated by plotting lnA against time ( t ). The kinetic measurements could be detected by both spectra scan and time-dependent decay measurements. Examination of the Arrhenius parameters reveals an underlying compensation between E a and log A , whereby an increase in E a is opposed by an increase in log A . The compensation appears in the corresponding Eyring parameters, Δ H ≠ and Δ S ≠ ; betaine structural changes that lead to lower, more favorable enthalpies of activation engender opposing entropic changes. At the isokinetic temperature T iso  =  β , structural changes do not affect the rate constant of a reaction series because the changes of Δ H ≠ are counterbalanced by changes of Δ S ≠ . The existence of an isokinetic relationship indicates a common structure of the transition state of all thermal back reaction of betaine under investigation. The computational results suggest that the decoloration reaction is a two-step mechanism. The first step corresponds to the transoid–cisoid isomerization with an activation barrier of 10.3 kJ mol −1 , and the second step is the ring closure from the cisoid intermediate with a barrier 71.3 kJ mol −1 , which represent the rate determining step for thermal decoloration. The photochemical ring opening of DHIs to betaines is a disrotatory 1,5-electrocyclic reaction, whereas the thermal ring-closing occurs in the conrotatory mode. Copyright © 2016 John Wiley & Sons, Ltd. The computational and experimental results suggest that the decoloration reaction is a two-step mechanism. The first step corresponds to the transoid-cisoid isomerization with an activation barrier of 10.3 kJ mol −1 , and the second step is the ring closure from the cisoid intermediate with a barrier of 71.3 kJ mol −1 , which represents the rate-determining step for thermal decoloration.

Description: Results from laboratory experiments on conservative density current confluence are reported. Hydraulic characteristics and morphodynamic consequences of the confluence of two continuous release density currents in a horizontal, 45 ∘ asymmetrical junction are examined and compared to those of terrestrial subaerial river junctions. It was observed that density current confluence is markedly different than those in river junctions primarily due to the ease of the dense fluid to convect into the ambient fluid in the junction zone. Upward convection in the junction resulted in low horizontal velocity and shear stresses on the bed of the junction zone, followed by re-plunging to the layer of neutral buoyancy downstream of the junction where acceleration occurs. In the downstream reach was a distinctive erosional pattern similar to central scouring seen in river junctions but starting at the downstream junction point rather than at the upstream junction point. It was found that terrestrial river models match well with the density current case in terms of maximum velocity downstream of the junction, backwater effect, scour face protrusion into the downstream reach, and maximum scour orientation. Poor matching was found in terms of separation zone dimensions and shape, streamline deviation angle on the junction line, and maximum scour depth.

Description: Temporal changes of seismic velocities may provide important information on the processes that occur inside the Earth. However, using body wave data with passive sources faces the problem of an uneven distribution of rays, which may cause artifacts with stronger amplitudes than the actual velocity changes in the Earth. We propose an algorithm for the selection of similar datasets in different time periods that minimize the artifacts related to variable data distributions. In this study, we used the data of the Japan Meteorological Agency for several years before and after the Mw 9.0 Tohoku-Oki event that occurred on 11 March 2011. We performed careful testing using different synthetic models, showing that the selected data subsets allow detecting weak velocity changes with amplitudes above 0.2%. The analysis of the experimental data revealed important features associated with the stress and deformation distributions after the megathrust event. In the upper crust, we found a large zone along the coast with significant P-velocity increase likely caused by compression of crustal rocks. This zone was cut by several elongated anomalies with local velocity decrease coinciding with the limits of the maximum slip area. These anomalies possibly mark the areas of major ruptures and deformations after the Tohoku-Oki earthquake. In the coupling zone at a depth of 40 km, we observe a velocity decrease in the area of the Mw7.7 aftershock representing strong fracturing in the focal zone. Beneath the volcanic arc, we observe significant (up to 0.5%) decrease of P-velocity, but less prominent S-velocity changes.

Description: Abstract U‐Th dating of carbonate veins in connection with active tectonics has recently been used as an attractive tool for constraining the absolute timing of late Quaternary crustal deformations. In this study, for the first time we correlate U‐Th ages of travertine deposits in coseismic fissures along the North Anatolian Fault Zone with records of paleoseismological studies supported by historical earthquake catalogued data. U‐Th ages are assessed in relation to the recurrence interval and the size and epicenter distance of major Holocene earthquakes. Our statistical evaluations on age correlations indicate that the carbonate vein precipitation is concentrated in eight different periods along the North Anatolian Fault Zone. The periods are well correlated with historical earthquake records and with previous dating results of the nearby trench studies. At least six of the periods correspond to the earthquakes reported in the historical catalogues. The age correlations of carbonate precipitation intervals for the last millennium show a recurrence along the eastern North Anatolian Fault Zone with a mode at 130–330 years that is consistent with a previously proposed paleoseismic recurrence interval of the fault. Recorded events in carbonate veins indicate a close‐epicenter (d 〈 200 km) and high‐intensity (I 〉 VI) paleoearthquakes. Our results suggest that coseismic carbonate veins could be used to determine paleoseismic records as a supplementary tool to augment paleoseismological techniques. This tool has advantages over traditional paleoseismological methods for the understanding of long‐term earthquake behavior, particularly for prehistoric late Pleistocene events which cannot be dated easily by traditional paleoseismological methods.

Description: Abstract Barrier islands are important landforms in many coastal systems around the globe. Studies of modern barrier island systems are mostly limited to those of siliciclastic realms, where the islands are recognized as mobile features that form on transgressive coastlines and migrate landward as sea‐level rises. Barrier islands of the ‘Great Pearl Bank' along the United Arab Emirates coast are the best‐known carbonate examples. These Holocene islands, however, are interpreted to be anchored by older deposits and immobile. The mid‐Holocene to late‐Holocene depositional system at Al Ruwais, northern Qatar, provides an example of a mobile carbonate barrier island system, perhaps more similar to siliciclastic equivalents. Sedimentological and petrographic analyses, as well as 14C‐dating of shells and biogenic remains from vibracored sediments and surface deposits, show that after 7000 years ago a barrier system with a narrow back‐barrier lagoon formed along what is now an exposed coastal zone, while, contemporaneously, a laterally‐extensive coral reef was forming immediately offshore. After 1400 years ago the barrier system was forced to step approximately 3 km seaward in response to a sea‐level fall of less than 2 m, where it re‐established itself directly on the mid‐Holocene reef. Since that time, the barrier has retreated landward as much as 1000 m to its current position, exposing previously‐deposited back‐barrier lagoonal sediment at the open‐coast shoreline. In modern neritic warm‐water carbonate settings mobile barrier island systems are rare. Their construction and migration may be inhibited by reef formation, early cementation, and the relative inefficiency of sourcing beach sediments from open carbonate shelves. Carbonate barrier island systems likely formed more commonly during geological periods when ramps and unrimmed shelves predominated and in calcite seas, when meteoric cementation was minimized as a result of initial calcitic allochem mineralogy. As with their siliciclastic analogues, however, recognition of the influence of these transient landforms in the rock record is challenging. This article is protected by copyright. All rights reserved.

Description: The objective of this study was to fabricate dual-layer hollow fiber as a microreactor for potential syngas production via phase inversion-based co-extrusion/cosintering process. As the main challenge of phase inversion is the difficulty to obtain defect-free fiber, this work focuses on the effect of the fabrication parameters, that is, nonsolvent content, sintering temperature and outer-layer extrusion rate, on the macrostructure of the produced hollow fiber. SEM images confirm that the addition of nonsolvent has successfully minimized the finger-like formation. At high sintering temperature, more dense hollow fiber was formed while outer-layer extrusion rate affects the outer layer thickness.

Description: This paper investigates the uncertainty of physically non-linear problems by modeling the elastic random material parameters as stochastic fields. For its stochastic discretization a polynomial chaos (PC) is used to expand the coefficients into deterministic and stochastic parts. Then, from experimental data for an adhesive material the distribution of the random variables, i.e. Young's modulus E (θ), the static yield point Y 0 and the nonlinear hardening parameters q and b , are known. In the numerical example the distribution of the stresses obtained by the PC based SFEM and Monte Carlo simulation is compared. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Description: Pre-drill overpressure prediction is important for well planning and migration modeling for prospect evaluation. The Eaton (1972) and Bowers (1995) methods are used worldwide for post drill overpressure prediction using sonic log and pre-drill overpressure prediction using seismic interval velocity. In this research, these two methods were used for overpressure prediction using 3D anisotropic prestack depth migrated seismic interval velocity in a field of the Malay Basin. In the shallow overpressured zone, where the mechanism of overpressure is undercompaction, the onset of overpressure was predicted reasonably well using the Eaton and Bowers methods with their standard parameters (i.e. Eaton exponent 3 and Bowers loading curve) for seismic velocity. However, in the deep overpressured zone, where fluid expansion is the cause of overpressure generation, these methods underpredicted the high overpressure. In the deep overpressured zone, the overpressures were better predicted by applying a correction to the Eaton method. On the other hand, the Bowers unloading parameters for the fluid expansion mechanisms did not show any significant effect on overpressure prediction. Hence, in the study area, the Bowers method is not effective for 3D overpressure prediction using seismic velocity, whereas, the Eaton method is more robust and can be used for 3D overpressure prediction from seismic velocity. This article is protected by copyright. All rights reserved.

Description: Abstract The relationship between the character of atmospheric blocking and surface temperature has not been studied in depth for Turkey. Here, these relationships are investigated for the period 1977 ‐ 2016. The seasonal mean temperature anomalies for all stations during blocked days varies between ‐2.1o C and 0.8o C. There are four main patterns representing the mean seasonal temperature anomalies for all stations during blocked and non‐blocked days. The annual cycle for each group is nearly opposite, and this indicates the impact of blocking on observed temperature, as blocked days comprised 30% of the study period. When focusing on the spatial distribution of mean seasonal anomalies, the winter and fall seasons show that, almost all stations have negative temperature anomalies although anomalies are close to zero during warm seasons (spring and summer). The composite analysis shows that the western part of the country is strongly affected by cold air advection during upstream blocking events and the eastern part of the country is affected by warm temperature advection for downstream blocking events. There is a statistically significant (95% confidence level) negative correlation between blocking intensity and temperature anomalies in all seasons except spring. There is no relationship between both blocking duration and longitudinal extent and the seasonal mean temperature anomaly except during winter, which has a significant negative correlation. The temperature anomaly distribution stratified by season shows that strong positive anomalies are rarely observed in all seasons. Only winter and spring were associated with very strong positive anomalies and only at a few stations. Rex‐type atmospheric blocking events are observed during the period of not only the maximum temperature anomaly but also for minimum anomalies. However, the location of the blocking event differed from the typical situation above, with the cold and warm events being located downstream and upstream of Turkey, respectively. This article is protected by copyright. All rights reserved.

Description: We present a new 3D anisotropic seismic model for the crust and upper mantle beneath Hokkaido (Japan) based on tomographic inversion of P- and S-arrival times from a regional seismic database. The P model is parameterized with three parameters at each point that describe the azimuthal anisotropy; the S model is represented isotropically. The isotropic P- and S-velocity anomalies match nearly perfectly. In the crust, they show a prominent linear anomaly in central Hokkaido along the Kamuikotan and Hidaka belts, which represents the area of eastward underthrusting of the Japan Block underneath the Kuril forearc. We interpret the high-velocity anomaly beneath the Hidaka zone as being delaminated mafic crust and entrained mantle lithosphere, which developed due to crustal shortening in the collision zone. One of our vertical sections shows a very unusual configuration for a subduction zone: a low-velocity slab is overlain by a high-velocity body in the mantle wedge. We propose that the high-velocity delaminated material sinking along the slab surface prevents the escape of fluids and melts from the upper part of the slab, where they are generated due to phase transitions. As a result, a large portion of the fluids is entrained downward and lowers the seismic velocities in the slab. The azimuthal anisotropy in the crust clearly corresponds to the major tectonic units and delineates the major suture zones. In the mantle, the anisotropy has a fan-shaped configuration and most likely represents the deviating of flows starting in southern Hokkaido and splitting into three directions. The western and eastern flows proceed toward the two volcanic groups on Hokkaido, and they may carry with them additional material to trigger the characteristic caldera-forming eruptions in these groups.