Mineralogy,petrology, chronology,and exposure history of the Chelyabinsk meteorite and parent body

Three masses of the Chelyabinsk meteorite have been studied with a wide range of analytical techniques to understand the mineralogical variation and thermal history of the Chelyabinsk parent body. The samples exhibit little to no postentry oxidation via Mössbauer and Raman spectroscopy indicating their fresh character, but despite the rapid collection and care of handling some low levels of terrestrial contamination did nonetheless result. Detailed studies show three distinct lithologies, indicative of a genomict breccia. A light‐colored lithology is LL5 material that has experienced thermal metamorphism and subsequent shock at levels near S4. The second lithology is a shock‐darkened LL5 material in which the darkening is caused by melt and metal‐troilite veins along grain boundaries. The third lithology is an impact melt breccia that formed at high temperatures (~1600 °C), and it experienced rapid cooling and degassing of S₂ gas. Portions of light and dark lithologies from Chel‐101, and the impact melt breccias (Chel‐102 and Chel‐103) were prepared and analyzed for Rb‐Sr, Sm‐Nd, and Ar‐Ar dating. When combined with results from other studies and chronometers, at least eight impact events (e.g., ~4.53 Ga, ~4.45 Ga, ~3.73 Ga, ~2.81 Ga, ~1.46 Ga, ~852 Ma, ~312 Ma, and ~27 Ma) are clearly identified for Chelyabinsk, indicating a complex history of impacts and heating events. Finally, noble gases yield young cosmic ray exposure ages, near 1 Ma. These young ages, together with the absence of measurable cosmogenic derived Sm and Cr, indicate that Chelyabinsk may have been derived from a recent breakup event on an NEO of LL chondrite composition.     

Preparation and charaterization of self-assembled nanoparticles based on linolenic-acid modified chitosan

1 IntroductionHydrophobically modified water-soluble polymers,also known as hydrophobized polymers, are thosemodified by hydrophobic groups such as alkyl,arolkyl, and deoxycholic acid. In water, they canself-aggregate due to their intro- and/or intermolecularhydrophobic interaction. By this process, unique hy-drogel nanoparticles with hydrophobic core and hy-drophilic shell can be prepared, which is a new ap-proach to preparing the monodispersed hydrogelnanoparticles (Whitesides et al., 1991; …     

Molecular expression of opsin gene in growing juvenile mackerel (<Emphasis Type="Italic">Scomber japonicus</Emphasis> Houttuyn)

Fish have developed color vision that is closely adapted to their photic environments, where both spectral sensitivity and the number of visual opsins are influenced. The mackerel used in this study is one of the most important fishery stocks in Korea. The opsin gene of the mackerel juveniles after 20 days in hatching was isolated and characterized based on the molecular study of visual photoreceptor. The full-length mackerel opsin gene was obtained by PCR amplification of genomic DNA, as well as cDNA synthesis. Sequence analysis of the opsin gene showed that it contained a 1,080 bp open reading frame encoding 360 amino acids. Based on Schiff’s base formation (S114, K119), glycosylation (E3, F37) and palmitoylation (S281, 282), the deduced amino acid sequence had a typical rod opsin. The mackerel and Gempylus serpens showed 73.7% DNA homology on opsin gene, which was higher than any other of investigated species. In the analysis of phylogenetic relationship, the genetic placement of the mackerel is closer to that of Scombroidei than Labroidei, with supporting somewhat strong bootstrap value. In the analysis of Northern and RT-PCR, the probed products were observed only in rapidly growing juveniles. These findings indicate that in mackerel opsin mRNA expression can be detected in day-20 hatching larvae. It may play an important role in stimulating growth hormone.     

Effect of connecting rain barrels on the storage size reduction

In this article, the possibility of sharing rain barrels and the potential benefit of reducing storage size through physical and non‐physical connections of rain barrels in a community are investigated. Using the concepts of homogeneous/heterogeneous users in rainwater harvesting systems (RWHS), two simple cases of a community composed of four prospective users are examined. The first is performed with the users who have the same mean and variance in water demands (homogeneous users), and the second is with the users with different means and variances (heterogeneous users). To take account for the rainfall characteristics in different places, historical records from six cities in the USA are used for storage–reliability–yield analysis. The result indicates that required total storage can be reduced by connecting multiple rain barrels. In addition, a significant difference is found between homogeneous and heterogeneous user groups. Homogeneous users do not achieve a substantial benefit from connecting their rain barrels; these users may even be disadvantaged by sharing. In contrast, heterogeneous users receive benefit by reducing the total required storage. Most benefit is expected between users with maximum difference in mean water demands. The reduction in storage size was as considerable as 37% in this study. The quantity of storage reduction depends on locations and target reliabilities. Knowledge of the benefits and limitations of rain barrel connections can improve RWHS performance through ability to customize a network plan for individual users. Copyright © 2011 John Wiley & Sons, Ltd.     

A framework for coupling shoals and shallow embayments with main channels in numerical modeling of coastal plain estuaries

A simple computational framework is developed to include shoals and shallow embayments (SSE) and their interaction with main channels in estuarine modeling. The scheme, treating SSE as temporary storage areas, accounts for the water and material exchanges between SSE and main channels as the tide rises and falls, and for the biogeochemical processes affecting nonconservative substances such as water-quality parameters in SSE. The scheme, because of its simple nature, can be easily incorporated into one-, two- or three-dimensional models of estuaries with substantial SSE. The concept and the model implementation of the scheme are explained using a vertical two-dimensional model of estuarine hydrodynamics and water quality. The model application to the tidal Rappahannock River, a western shore tributary of Chesapeake Bay, demonstrates the scheme is simple and physically reasonable, and the importance of SSE in estuarine modeling. The inclusion of SSE in a water-quality model not only provides a framework, for computing water-quality conditions therein but also accounts for the interaction between SSE and the main channel. It is shown that significant errors may result if the effects of SSE are not properly accounted for in modeling of an estuary with extensive SSE.     

Tectonic evolution at an early proterozoic continental margin: The Svecokarelides of eastern Finland

The early Proterozoic history of the Baltic Shield in Fennoscandia provides evidence of fragmentation of a late Archaean craton, continental sedimentation and then back-arc spreading, interpreted as being associated with the uprise of a mantle diapir. Basin subsidence and infilling with flysch debris is explained on the basis of thermal decay, locking of a subduction zone and erosion of an uplifted arc. Compressive tectonism in the Karelian part of the Svecokarelian orogen resulted in obduction of the contents of the back-arc basin on to the continental foreland. Further compression caused further thickening of the supracrustal pile and interdigitation of tectonic slices of basement and cover due to thrusting. Subsequently movement was resolved along major NW-trending wrench-faults that generally follow the margin of teh craton and which represent zones of reactivation of planar features developed in late Archaean times. As the crustal pile was warped and uplifted in subsequent deformational phases, the deep levels of the wrench-faults acted as sites of granitoid emplacement.The tectonic activity in the Karelian part of the Svecokarelides is interpreted as the response to the northward movement of oceanic lithosphere in the Svecofennian part of the orogen where successively-formed early Proterozoic island arcs moved northwards and were intensely deformed, associated with the development and emplacement of large masses of igneous material. The resultant orogen, consisting of a stable craton, obducted nappes, exotic terrane, transcurrent faults and island arcs that moved obliquely to the margin of the craton, shows many similarities in development to that of the western Cordillera of North America.     

Focal mechanisms of recent earthquakes in the Southern Korean Peninsula

We evaluate the stress field in and around the southern Korean Peninsula with focal mechanism solutions, using the data collected from 71 earthquakes ( M_L = 1.9–5.2) between 1999 and 2004. For this, the hypocentres were relocated and well-constrained fault plane solutions were obtained from the data set of 1270 clear P -wave polarities and 46 SH / P amplitude ratios. The focal mechanism solutions indicate that the prevailing faulting types in South Korea are strike-slip-dominant-oblique-slip faultings with minor reverse-slip component. The maximum principal stresses (σ₁) estimated from fault-slip inversion analysis of the focal mechanism solutions show a similar orientation with E–W trend (269°–275°) and low-angle plunge (10°–25°) for all tectonic provinces in South Korea, consistent with the E–W trending maximum horizontal stress (σ_Hmax) of the Amurian microplate reported from in situ stress measurements and earthquake focal mechanisms. The directions of the intermediate (σ₂) and minimum (σ₃) principal stresses of the Gyeongsang Basin are, however, about 90 deg off from those of the other tectonic provinces on a common σ₂–σ₃ plane, suggesting a permutation of σ₂ and σ₃. Our results incorporated with those from the kinematic studies of the Quaternary faults imply that NNW- to NE-striking faults (dextral strike-slip or oblique-slip with a reverse-slip component) are highly likely to generate earthquakes in South Korea.     

Evaluation of density in layer compaction using SASW method

SASW test, which is non-intrusive and rapid in the field application, was used to evaluate the layer density in the roller compaction without performing the complicated inversion process. The concept of normalized shear wave velocity was introduced to minimize the effect of confinement in the density evaluation. SASW test was performed to determine the shear wave velocity of the layer, and the free–free resonant column (FF–RC) test was adopted to determine the correlation between the normalized shear wave velocity and density of the site, which is almost unique independent of confinement. Testing and data reduction procedures of both tests were briefly discussed and an evaluation procedure of the field density was proposed by effectively combining in-situ shear wave velocity determined by the SASW test with the correlation between the normalized shear wave velocity and the density determined by the FF–RC test. Finally, the feasibility of the proposed method was verified by performing a field case study at Hoengsung road construction site. Field densities determined by the proposed method matched well with those determined by sand cone tests, showing the potential of applying the proposed method in the field density evaluation.