Photometric Investigation of Contact Binary DY Cet Based on TESS Data

We present a photometric analysis of the Transiting Exoplanet Survey Satellite(TESS) light curve of contact binary system DY Cet and the behavior of its orbital period variation.The light curve and published radial velocity data analysis was performed using the Wilson-Devinney code.As a result of simultaneous analysis of the light curve with radial velocity data,the masses and radii of the system’s components were determined as M₁=1.55±0.02 M_⊙,M₂=0.55 ± 0.01 M_⊙ and R_...     

Evolution of mine-pool chemistry at the Sydney Coalfield, Nova Scotia, Canada, and its implications for mine decommissioning

The Sydney Coalfield is the largest in Atlantic Canada in which about 100 coal mines with varied lifespan have been opened since 1720. In the Glace Bay sub-basin, coal seams subcrop close to the Atlantic coast and dip seaward. Coal has been mined at 〉1200 m depth and 11 km from the coastline. Deposited possibly under a marine influence, the coals are enriched in pyrite. During mining abundant acidic sulfates such as melanterite, rozenite, copiapite and halotrichite have accumulated in the underground workings due to pyrite oxidation. The dissolution of these efflorescent salts upon mine flooding at closure gives rise to acidic mine pools wherever insufficient acid-neutralizing materials are present. A major challenge of mine decommissioning in the area is to prevent the discharge of this acidic water into the open ocean. Water monitoring in the 1B Hydraulic System, which consists of ten mines connected at various depths by natural or man-made conduits, shows that the mine pool chemistry varies with the mining practice employed. Although coal has invariably been mined by the room and pillar method, the extent of pillar removal varies from mine to mine. In mines with minimal pillar removal, coal extraction could be as low as 45%, leaving much pyrite for oxidation prior to eventual flooding and an acidic mine pool occurs. In contrast, in mines with extensive pillar removal, coal extraction could amount to 85%, leaving much less pyrite for oxidation. Moreover, the extensive pillar removal caused the collapse of the overlying strata which in some areas include limestone. The infilling of mine workings with carbonate-rich material offsets the effects of acidic effiorescent salts and a mine pool with near-neutral pH results. Geochemical modeling has affirmed the control of local water chemistry by the prevalent mineral assemblage.     

Notes on the Stratigraphy of the Chinglung Limestone of the Lower Yangtze Valley

The object of this paper is to describe some typical sections of theTriassic Chinglung limestone (青龙石灰岩) in the Lower Yangtze Valleyso that sections in other parts of South China may be compared, both asto stratigraphy and as to fauna, with that of the type area. The name,     

Molecular and stable carbon isotopic characterization of PAH contaminants at McMurdo Station, Antarctica

The molecular and stable carbon isotopic compositions of contaminant polycyclic aromatic hydrocarbons (PAHs) at McMurdo Station, Antarctica were analyzed in samples collected from land and sub-tidal area. PAHs in the study areas were characterized by high amounts of naphthalene and alkylated naphthalenes from petroleum products introduced by human activities in the area. Principal component analysis (PCA) of PAH composition data identified multiple sources of PAH contamination in the study area. Compositional assignments of origins were confirmed using compound specific stable carbon isotopic analysis.     

Dissimilarity among Ocean Reanalyses in Equatorial Pacific Upper-Ocean Heat Content and Its Relationship with ENSO

This study focuses on the temporal variation of dissimilarity in heat content(HC)anomalies in the upper 300 m of ocean(HC300A)in the equatorial Pacific(±10°N)and its response to the El Ni?o-Southern Oscillation(ENSO).The HC300A anomalies are derived from four ocean reanalyses that are commonly used in ENSO studies and are compared using a simple differencing method.The dissimilarity in HC300A is found to vary closely with the magnitude of ENSO(regardless of phase),meaning that it tends to be greater during strong ENSO events.However,the dissimilarity among ocean reanalyses persists after the event decays.This effect is more pronounced after strong events.The persistence of the dissimilarity after ENSO events is a result of a late maturation of the ENSO signal,its persistence,and the interruption of the signal decay due to follow-up ENSO events.The combined effect of these three factors slows down the decay of HC300A in the region and hence results in the slow decay of dissimilarity.It is also found that areas with a significant spread in vertical temperature profiles collocate with the ENSO signal during warm ENSO phases.Thus,differences in subsurface process reconstruction are a significant factor in the dissimilarity among ocean reanalyses during warm ENSO events.     

The French approach to managing water resources in the Mediterranean and the new European Water Framework Directive

The main content of the new European Water Framework Directive is presented. Within its river basin management approach, a special mention of coastal waters status is made. Among the issues at stake are the setting up of river basin management plans, including coastal waters, and water quality assessment system leading to an harmonized definition of quality objectives and their appropriate indicators. The Rhone-Mediterranean-Corsica Water Master Plan, launched in 1996, is considered to be well fitted to this river basin approach and the necessary tools which go with it. It shows up how a river quality assessment system (SEQ) can be adapted to the coastal waters and how it can progressively lead to an efficient set of publishable environmental and performance indicators. Since planning and implementation are devolved to the lowest appropriate level, a close look is then been given at how such a system can work at the local level through different selected case studies on the French Mediterranean coast. In conclusion, some guidelines are drawn up for future initiatives towards integrated coastal area and river basin management.     

Effects of spilled oil on microbial communities in a tidal flat

Effects of spilled oil on microbial communities in tidal flats were examined by use of a simulator for a tidal flat ecosystem. The simulator is composed of a wave generator, a tide control device, and a tidal flat. Sediment for the tidal flat was obtained at a natural tidal flat in Hiroshima Bay, Japan. After stabilizing the benthic organisms, fuel oil C was added to the surface of the flat at 1 lm(-2). Although the total number of micro-organisms remained at 1.5-3.5 x 10(9) cells g(-1) dry sediment irrespective of the addition of oil, bacterial communities which were analyzed based on the 16S rDNA showed clear changes after the addition of fuel oil C and after a subsequent recovery period. Bacterial colonies were randomly isolated from the oil-supplemented sediment during the experiments, and the isolates were examined for susceptibility to hydrocarbons in order to screen the oil-susceptible bacteria. The proportion of oil-susceptible bacteria in the isolates decreased with the addition of the oil. Oil-susceptible bacteria showed an inability to assimilate petroleum compounds as well as an inhibition of growth. The possibility of using oil-susceptible bacteria as an indicator of bioremediation in tidal flats was discussed.     

Effects of gas generation and precipitates on performance of Fe0 PRBs

Long-term reactivity and permeability are critical factors in the performance of granular iron permeable reactive barriers (PRBs). Thus it is a topic of great practical importance, as well as scientific interest. In this study, four types of source solutions (distilled H2O, 10 mg/L TCE, 300 mg/L CaCO3, and 10 mg/L TCE + 300 mg/L CaCO3) were supplied to four columns containing a commercial granular iron material. In all four columns, gases accumulated to approximately 10% of the initial porosity and resulted in declines in permeability of approximately 50% to 80%. In the columns receiving CaCO3, carbonate precipitates accumulated to approximately 7% of the initial porosity, with no apparent decline in permeability. The data indicate that precipitates formed initially at the influent ends of the columns, reducing the reactivity of the iron in this region. As a consequence of the reduced reactivity, calcium and bicarbonate migrated further into the column, to precipitate in a region where the reactivity remained high. Thus precipitation occurred as a moving front through the columns. The results suggest improved methods for PRB design and rehabilitation, and also suggest improvements that are needed in the mathematical models developed for predicting long-term performance.