Spectroscopic study of the eclipsing binary V 367 Cygni

Seventeen coudé spectrograms (dispersion 20 A mm^–1) of the Lyrae-type eclipsing binary V 367 Cygni (P=18.6 d) have been studied. The observations were made at the Haute Provence Observatory during a period of almost two years (May 1973–March 1975). An anomalous behavior for the radial velocities of the spectrograms taken during one cycle (406) was observed; it is suggested that gas eruption under form of prominences may explain it. The spectrum is dominated by shell lines very similar to those present in the spectrum of the supergiant A9 Ia Aurigae. The underlying stellar spectrum is classified as A5 I on the basis of the intensity of the sole clearly visible stellar line, 4481 MgII, of the wings of the stellar Balmer lines, and an estimate of the intensity of the stellarK line. The radial velocity curves for the shell lines of CaII, HI, metallic ions and neutral iron, as well as the phase dependence of the microturbulence, indicate stratification in the shell.     

The role of in situ stress in determining hydraulic connectivity in a fractured rock aquifer (Australia)

Fracture network connectivity is a spatially variable property that is difficult to quantify from standard hydrogeological datasets. This critical property is related to the distributions of fracture density, orientation, dimensions, intersections, apertures and roughness. These features that determine the inherent connectivity of a fracture network can be modified by secondary processes including weathering, uplift and unloading and other mechanisms that lead to fracture deformation in response to in situ stress. This study focussed on a fractured rock aquifer in the Clare Valley, South Australia, and found that fracture network connectivity could be discriminated from several geological, geophysical and hydrogeological field datasets at various scales including single well and local- to regional-scale data. Representative hydromechanical models of the field site were not only consistent with field observations but also highlighted the strong influence of in situ stress in determining the distribution of fracture hydraulic apertures and the formation of hydraulic chokes that impede fluid flow. The results of this multi-disciplinary investigation support the notion that the hydraulic conductivity of a fracture network is limited to the least hydraulically conductive interconnected fractures, which imposes a physical limit on the bulk hydraulic conductivity of a fractured rock aquifer.     

Wear Performance of Saw Blades in Processing of Granitic Rocks and Development of Models for Wear Estimation

This study investigates the wear performance of diamond circular saw blades in cutting of granitic rocks. An alternative wear measuring method is developed to measure the reduced blade radius without taking the blade off the machine. The effect on and contribution to the specific wear rate (SWR) of each operating variable are determined, and the SWR is correlated with rock properties. Morphologies of wearing surfaces of segments and rocks are also evaluated using scanning electron microscopy (SEM). Depending on both operating variables and rock properties, prediction models are developed for estimation of the SWR. Results show that the SWR increases with an increase in the peripheral speed and the traverse speed, while it decreases with an increase in the cutting depth and the flow rate of the cooling fluid. The peripheral speed, and the microhardness and proportions of minerals such as quartz, plagioclase, and feldspar are statistically determined as the significant variables affecting the SWR. Finally, it is disclosed that models developed for estimation of SWR have great potential for practical applications.     

Magnetic susceptibility and heavy-metal contamination in topsoils along the Izmit Gulf coastal area and IZAYTAS (Turkey)

The study on topsoil contamination due to heavy metals was carried out by using the Magnetic susceptibility (MS) measurements in Izmit industrial city, northern Turkey. We attempted to investigate correlations between the concentration of selected heavy metals and the MS from 41 sample sites around Izmit Gulf. These investigations let us quantify and standardize the MS method, which may have consequences for long term monitoring of anthropogenic pollution, especially in urban areas. The MS surfer contour map based on the topsoil measurements was compiled with a randomly ranged distance density. The soil samples collected throughout the industrial areas, the parks, road sides and residential areas were also analyzed by Atomic Absorption Spectrometer. Heavy metals Cu, Ni, Cr and Pb show strong correlations with MS, while Zn and Co show a weak correlation with MS. Moreover, the Tomlinson pollution load index (PLI) shows insignificant correlation with the MS.The MS was examined vertically (0–30 cm) with respect to anthropogenic and/or lithogenic influences at the fourteen sample sites. The maximum values were mostly observed in depths of 2–5 cm and the MS values on the depth profiles vary between 10 × 10^? 8 m³ kg^? 1 and 203 × 10^? 8 m³ kg^? 1. The study revealed that MS is an inexpensive, fast and non-destructive method for the detection and mapping of contaminated soils.     

Assessment and analysis of rockfall-caused tree injuries in a Turkish fir stand: A case study from Kastamonu-Turkey

Rockfalls can cause serious damage to people,property,facilities and transportation corridors.Furthermore,rockfalls are major hazards in mountain areas with negative impacts on individual trees and forested ecosystems.We conducted a study of rockfall events on 117 mapped(91% of total trees in the stand with1.3 m in height and5 cm diameter at breast height)Turkish fir trees(Abies bornmuelleriana Mattf.)in a stand within the Kayaarkasi-Topular Village,Inebolu district, Kastamonu province of Turkey.The study site of 0.35 Ha is located on the transition zone of frequently passing rockfall fragments(～40 cm in diameter) generally causing healable injuries.Parameters of trees and injuries were recorded and analysed as to injury number,height and size.Bivariate correlation analysis were used to investigate the relationships between:a)diameter at breast height and number of injuries per tree,b)diameter at breast height and total injury size,c)the number of injuries and total injury size and d)the number of injuries per tree and distance from the source of the rockfall area.Results indicate that the average height of injury,average number of injuries and average injury area to be 81.3 cm(STDEV:49.8),7.46(STDEV:4.4)and 628.6 cm2 (STDEV:678.2),respectively.In total 84% of all injuries were recorded within 160°sector at the upslope side of trees and callus tissue that had closed wounds was observed in 79.1% of all injuries. Furthermore 14.5% of injured trees had callus tissue in the process of closing wounds while 6.4% of injuries had not formed any callus tissue.The most common injury types were bark and wood injuries. Bivariate correlation analysis indicated strong relationships between diameter at breast height and the number of injuries(rs=0.524),injury number and total injury area(rs=0.653)and distance from rockfall area and injury numbers relations(rs=-0.518).A weaker relationship was found between diameter at breast height and total injury area(rs=0.363).These results indicate that bigger trees are more prone to rockfall injuries.As expected,trees further from the rockfall area seem to be less prone to rockfall injuries.From our results,it can be inferred that the protection of people and property can be increased through the maintanance of forest in areas immediately below areas prone to rockfall.This stand is still managed in selective forest management system.In order to protect the settlement at the deposition zone it has to manage for protective goals with uneven-aged and multilayered stand structure.     

Insight into the effects of clay mineralogy on the cyclic behavior of silt–clay mixtures

Results of a systematic testing program showed that the cyclic behavior of silt–clay mixtures is greatly influenced by the dominant clay minerals in the mixture. In particular, it was demonstrated that given the same amount of clay/clay mineral and/or same value of plasticity index, the montmorillonitic soils have the highest cyclic strength, followed by the illitic soils, and then by the kaolinitic soils. Moreover, the rate of increase in cyclic strength with increasing % clay mineral and PI is again the highest in the montmorillonitic soil, lowest in the kaolinitic soil and intermediate in the illitic soil. Therefore, without considering clay mineralogy, the % clay fraction, % clay mineral and plasticity index are unreliable indicators of the liquefaction susceptibility of fine-grained soils. The differing adhesive bond strength each clay mineral develops with the silt particles is deemed to largely explain the observed differences in the response of the three different soil mixtures to cyclic loading.     

Rupture progression along discontinuous oblique fault sets: implications for the Karadere rupture segment of the 1999 Izmit earthquake, and future rupture in the Sea of Marmara

Large earthquakes in strike-slip regimes commonly rupture fault segments that are oblique to each other in both strike and dip. This was the case during the 1999 Izmit earthquake, which mainly ruptured E–W-striking right-lateral faults but also ruptured the N60°E-striking Karadere fault at the eastern end of the main rupture. It will also likely be so for any future large fault rupture in the adjacent Sea of Marmara. Our aim here is to characterize the effects of regional stress direction, stress triggering due to rupture, and mechanical slip interaction on the composite rupture process. We examine the failure tendency and slip mechanism on secondary faults that are oblique in strike and dip to a vertical strike-slip fault or “master” fault. For a regional stress field well-oriented for slip on a vertical right-lateral strike-slip fault, we determine that oblique normal faulting is most favored on dipping faults with two different strikes, both of which are oriented clockwise from the strike-slip fault. The orientation closer in strike to the master fault is predicted to slip with right-lateral oblique normal slip, the other one with left-lateral oblique normal slip. The most favored secondary fault orientations depend on the effective coefficient of friction on the faults and the ratio of the vertical stress to the maximum horizontal stress. If the regional stress instead causes left-lateral slip on the vertical master fault, the most favored secondary faults would be oriented counterclockwise from the master fault. For secondary faults striking ±30° oblique to the master fault, right-lateral slip on the master fault brings both these secondary fault orientations closer to the Coulomb condition for shear failure with oblique right-lateral slip. For a secondary fault striking 30° counterclockwise, the predicted stress change and the component of reverse slip both increase for shallower-angle dips of the secondary fault. For a secondary fault striking 30° clockwise, the predicted stress change decreases but the predicted component of normal slip increases for shallower-angle dips of the secondary fault. When both the vertical master fault and the dipping secondary fault are allowed to slip, mechanical interaction produces sharp gradients or discontinuities in slip across their intersection lines. This can effectively constrain rupture to limited portions of larger faults, depending on the locations of fault intersections. Across the fault intersection line, predicted rakes can vary by >40° and the sense of lateral slip can reverse. Application of these results provides a potential explanation for why only a limited portion of the Karadere fault ruptured during the Izmit earthquake. Our results also suggest that the geometries of fault intersection within the Sea of Marmara favor composite rupture of multiple oblique fault segments.