Geochemical characteristics of mineral air particles emitted inside a clay atomisation plant which introduces waste recycling processes

The objective of this work is to assess the concentrations of three factions of air particles (settable particles, TSP and PM10) and the levels of several toxic elements in a clay atomisation industry through aerosol sampling at several points inside an industrial plant. Mechanical activities, which produce diffuse emissions, are the main process of discharge of particles in both indoor and outdoor workplace environments in the atomisation plant. The levels of As, Cd, Pb, Zn, Ba and Ni increase in the zones with higher concentrations of particles and lower ventilation. The concentrations of As and F are not influenced by the recycling processes. The levels of Cd and Pb do not show great enrichment in air particles collected inside the atomisation plant although the content of both elements is associated with ceramic muck recycling. Finally, the content of B in waste water is mainly transferred in gaseous phase to the atmosphere during the process of drying by atomisation.     

土地利用/土地覆被变化遥感监测研究

根据1990年和1999年两期TM/ETM 遥感数据,运用遥感分类中的监督分类方法,全面分析乌鲁木齐市的土地利用的数量变化特征和空间变化特征,阐明了区域土地利用变化的区域特点。     

Triassic warm subduction in northeast Turkey: Evidence from the Ağvanis metamorphic rocks

Within the Tethyan realm, data for the subduction history of the Permo–Triassic Tethys in the form of accretionary complexes are scarce, coming mainly from northwest Turkey and Tibet. Herein we present field geological, petrological and geochronological data on a Triassic accretionary complex, the A?vanis metamorphic rocks, from northeast Turkey. The A?vanis metamorphic rocks form a SSE–NNW trending lozenge‐shaped horst, ～20 km long and ～6 km across, bounded by the strands of the active North Anatolian Fault close to the collision zone between the Eastern Pontides and the Menderes–Taurus Block. The rocks consist mainly of greenschist‐ to epidote‐amphibolite‐facies metabasite, phyllite, marble and minor metachert and serpentinite, interpreted as a metamorphic accretionary complex based on the oceanic rock types and ocean island basaltic, mid‐ocean ridge basaltic and island‐arc tholeiitic affinities of the metabasites. This rock assemblage was intruded by stocks and dikes of Early Eocene quartz diorite, leucogranodiorite and dacite porphyry. Metamorphic conditions are estimated to be 470–540°C and ～0.60–0.90 GPa. Stepwise ⁴⁰Ar/³⁹Ar dating of phengite–muscovite separates sampled outside the contact metamorphic aureoles yielded steadily increasing age spectra with the highest incremental stage corresponding to age values ranging from ～180 to 209 Ma, suggesting that the metamorphism occurred at ≥ 209 Ma. Thus, the A?vanis metamorphic rocks represent the vestiges of the Late Triassic or slightly older subduction in northeast Turkey. Estimated P–T conditions indicate higher temperatures than those predicted by steady state thermal models for average subduction zones, and can best be accounted for by a hot subduction zone, similar to the present‐day Cascadia. Contact metamorphic mineral assemblages around an Early Eocene quartz diorite stock, on the other hand, suggest that the present‐day erosion level was at depths of ～14 km during the Early Eocene, indicative of reburial of the metamorphic rocks. Partial disturbance of white‐mica Ar–Ar age spectra was probably caused by the reburial coupled with heat input by igneous activity, which is probably related to thrusting due to the continental collision between Eastern Pontides and the Menderes–Taurus Block.     

Impact of sensor measurement error on sensor positioning in water quality monitoring networks

This paper studies the impact of sensor measurement error on designing a water quality monitoring network for a river system, and shows that robust sensor locations can be obtained when an optimization algorithm is combined with a statistical process control (SPC) method. Specifically, we develop a possible probabilistic model of sensor measurement error and the measurement error model is embedded into a simulation model of a river system. An optimization algorithm is used to find the optimal sensor locations that minimize the expected time until a spill detection in the presence of a constraint on the probability of detecting a spill. The experimental results show that the optimal sensor locations are highly sensitive to the variability of measurement error and false alarm rates are often unacceptably high. An SPC method is useful in finding thresholds that guarantee a false alarm rate no more than a pre-specified target level, and an optimization algorithm combined with the thresholds finds a robust sensor network.     

Tsunami risk assessment: economic,environmental and social dimensions

Natural Hazards - In this study, we present a novel methodology that may be used to analyze tsunami risk along coastal regions. The application of the proposed methodology is demonstrated for the...     

Flow against dispersion in two-dimensional regions

In field applications, upstream spreading of contaminant plumes may be controlled by the flow of fresh water in a direction opposite to the dispersive expansion direction of the plume. In the current literature this type of control is identified as flow against dispersion or contrary flow. In this study analytic methods are used to investigate contrary flow conditions for two-dimensional applications. In particular, special attention is given to the dispersive spread of the contaminant plume in the transverse direction under equilibrium flow against dispersion. Typical problems analyzed emphasize the effect of adsorption and transverse dispersion on the overall control process. Problems analyzed indicate that equilibrium flow velocities deduced from one-dimensional analysis, which may balance the dispersive spread of the plume in the longitudinal direction, represent an over design condition when these equilibrium velocities are compared with the conditions generated from a two-dimensional model for a downstream source which is finite in the transverse direction.     

Stratigraphic and metamorphic inversions in the central Menderes Massif: a new structural model

The Menderes Massif is a large area of dominantly Tertiary metamorphic rocks in western Turkey. It is bordered in the west by the Cycladic Metamorphic Complex with Eocene high-pressure/low-temperature (HP/LT) metamorphism. In the Central Menderes the AydLn mountains are made up of a thrust stack of Eocene age. At the base of the thrust stack, greenschist-facies Paleozoic metasediments of the Menderes Massif form an inverted stratigraphic sequence. The Barrovian-type metamorphism is also inverted with garnet-bearing metapelites lying over the lower-grade biotite-bearing metapelites. The P-T conditions in the garnet zone are estimated as 530°C and 8 kbar. This schist sequence of the central Menderes Massif is interpreted as the inverted lower limb of a major southward closing recumbent fold, with the southern Menderes Massif representing a section from the near hinge of this fold. The Paleozoic metamorphic rocks of the central Menderes Massif are tectonically overlain by gneiss klippen possibly originating from the sheared and southward translated core of the Menderes fold. Lying also tectonically over the Paleozoic metamorphic rocks is a major thrust sheet belonging to the Cycladic metamorphic complex. It consists of garnet micaschist, Mesozoic marble, serpentinite and amphibolitised eclogite. Although it has a highly sheared internal structure, it probably represents an initially coherent sequence that has undergone HP/LT metamorphism during the Eocene. The AydLn mountains are dominated by contractional structures with subordinate extensional structures.