Semi‐active tuned mass damper building systems: Application

Seismic performance attributes of multi‐story passive and semi‐active tuned mass damper (PTMD and SATMD) building systems are investigated for 12‐story moment resisting frames modeled as ‘10+2’ stories and ‘8+4’ stories. Segmented upper portion of the stories are isolated as a tuned mass, and a passive viscous damper or semi‐active resetable device is adopted as energy dissipation strategy. The semi‐active approach uses feedback control to alter or manipulate the reaction forces, effectively re‐tuning the system depending on the structural response. Optimum tuned mass damper control parameters and appropriate matching SATMD configurations are adopted from a companion study on a simplified two‐degree‐of‐freedom system. Statistical performance metrics are presented for 30 probabilistically scaled earthquake records from the SAC project. Time history analyses are used to compute response reduction factors across a wide range of seismic hazard intensities. Results show that large SATMD systems can effectively manage seismic response for multi‐degree‐of freedom systems across a broad range of ground motions in comparison to passive solutions. Specific results include the identification of differences in the mechanisms by which SATMD and PTMD systems remove energy, based on the differences in the devices used. Additionally, variability is seen to be tighter for the SATMD systems across the suites of ground motions used, indicating a more robust control system. While the overall efficacy of the concept is shown the major issues, such as isolation layer displacement, are discussed in detail not available in simplified spectral analyses, providing further insight into the dynamics of these issues for these systems. Copyright © 2009 John Wiley & Sons, Ltd.     

A 60-year record of rainfall from the sediments of Jinheung Pond,Jeongeup, Korea

This paper describes mean grain-size data from the ¹³⁷Cs- and ²¹⁰Pb-dated sediment core BS-3 (33-cm long) recovered from Jinheung Pond, located in the southwestern part of the Korean Peninsula. Grain-size analysis of the Jinheung Pond sediments shows a clear signal for changes in annual precipitation over the past 60 years. Instrumental records of annual precipitation (AP) and the annual summation of the precipitation of >50 mm per day (AP50), which reflects the energy available for sediment transport, correlate well with the mean grain-size distributions measured in the core. The most plausible mechanism for this response in mean grain size is variations in the annual amount and intensity of precipitation. Heavy precipitation enhances soil erosion over the catchment area and increases the transport capacity of streams and rivers. Thus, coarser mean grain size should reflect higher precipitation, and smaller mean grain size should reflect lower rainfall. In the data from core BS-3, however, grain-size peaks attributed to increased annual precipitation are not prominent. This is because a dam prevents removal of fine particles from the pond via the outflow. Therefore, the mean grain-size value represents somewhat larger sediments together with fine clays. The results of this study show that sediments of dammed lakes and ponds are well suited for high-resolution environmental investigations, especially for records of changes in precipitation over time.     

Erratum to: Cloning, characterization, and expression analysis of the DEAD-box family genes, Fc-vasa and Fc-PL10a, in Chinese shrimp (Fenneropenaeus chinensis)

<正>In the original article, the name of the fourth author is incorrect. The correct one is Kyoung Ho Kang, in which "Kang" is the family name. The publishing companies apologize to the author.     

Soft‐sediment deformation structures in Cretaceous non‐marine deposits of southeastern Gyeongsang Basin,Korea: Occurrences and origin

A variety of soft‐sediment deformation structures formed during or shortly after deposition occurs in the Cretaceous Seongpori and Dadaepo Formations of the southeastern Gyeongsang Basin exposed along coastal areas of southeastern Korean Peninsula for 0.5–2 km. These are mostly present in a fluvial plain facies, with interbedded lacustrine deposits. In this study, the features of different kinds of soft‐sediment deformation structures have been interpreted on the basis of sedimentology of structure‐bearing deposits, comparison with normal sedimentary structures, timing and mechanism of deformation, and triggering mechanisms. The soft‐sediment deformation structures can be classified into four morphological groups: (i) load structures (load casts, ball‐and‐pillow structures); (ii) soft‐sediment intrusive structures (dish‐and‐pillars, clastic dykes, sills); (iii) ductile disturbed structures (convolute folds, slump structures); and (iv) brittle deformation structures (syndepositional faulting, dislocated breccia). The most probable triggering mechanisms resulting in these structures were seismic shocks. These interpretations are based on the following field observations: (i) location of the study area within tectonically active fault zone reactivated several times during the Cretaceous; (ii) deformation structures confined to single stratigraphic levels; (iii) lateral continuity and occurrences of various soft‐sediment deformation structures in the deformed level over large areas; (iv) absence of depositional slope to indicate gravity sliding or slumping; and (v) similarity to the structures produced experimentally. The soft‐sediment deformation structures in the study areas are thus interpreted to have been generated by seismic shocks with an estimated magnitude of M > 5, representing an intermittent record of the active tectonic and sedimentary processes during the development and evolution of two formations from the late Early Cretaceous to the Late Cretaceous.     

Near real-time high-resolution airborne camera,AEROCam, for precision agriculture

Precision agriculture often relies on high-resolution imagery to delineate the variability within a field. Airborne Environmental Research Observational Camera (AEROCam) was designed to meet the needs of agriculture producers, ranchers, and researchers, who require high-resolution imagery in a near real-time environment for rapid decision support. AEROCam was developed and operated through a unique collaboration between several departments at the University of North Dakota, including the Upper Midwest Aerospace Consortium (UMAC), the School of Engineering and Mines, and flight operations at the John D. Odegard School of Aerospace Sciences. AEROCam consists of a Redlake MS4100 area-scan multi-spectral digital camera that features a 1920 × 1080 CCD array (7.4-μm detector) with 8-bit quantization. When operated at ～2 km above ground level, multispectral images with four bands in the visible and near infrared have a ground sample distance of 1 m with a horizontal extent of just over 1.6 km. Depending on the applications, flying at different altitudes can adjust the spatial resolution from 0.25 to 2 m. Rigorous spectral and radiometric calibrations allow AEROCam to be used in a variety of applications, qualitative and quantitative. Equipped with an inertial measurement unit (IMU) system, the images acquired can be geo-referenced automatically and delivered to end users near real time through our Digital Northern Great Plains system (DNGP). The images are also available to zone mapping application for precision farming (ZoneMAP), an online decision support tool for creating management zones from remote sensing imagery and data from other sources. Operational since 2004, AEROCam has flown over 250 sorties and delivered over 150,000 images to the users in the Northern Great Plains region, resulting in numerous applications in precision agriculture and resource management.     

Effects of an Omnivorous Katydid,Salinity, and Nutrients on a Planthopper-<Emphasis Type="Italic">Spartina</Emphasis> Food Web

Top–down and bottom–up effects interact to structure communities, especially in salt marshes, which contain strong gradients in bottom–up drivers such as salinity and nutrients. How omnivorous consumers respond to variation in prey availability and plant quality is poorly understood. We used a mesocosm experiment to examine how salinity, nutrients, an omnivore (the katydid Orchelimum fidicinium) and an herbivore (the planthopper Prokelisia spp.) interacted to structure a simplified salt marsh food web based on the marsh grass Spartina alterniflora. Bottom–up effects were strong, with both salinity and nutrients decreasing leaf C/N and increasing Prokelisia abundance. Top–down effects on plants were also strong, with both the herbivore and the omnivore affecting S. alterniflora traits and growth, especially when nutrients or salt were added. In contrast, top–down control by Orchelimum of Prokelisia was independent of bottom–up conditions. Orchelimum grew best on a diet containing both Spartina and Prokelisia, and in contrast to a sympatric omnivorous crab, did not shift to an animal-based diet when prey were present, suggesting that it is constrained to consume a mixed diet. These results suggest that the trophic effects of omnivores depend on omnivore behavior, dietary constraints, and ability to suppress lower trophic levels, and that omnivorous katydids may play a previously unrecognized role in salt marsh food webs.     

Major human Hepatitis A virus genotype in Hong Kong marine waters and detection by real-time PCR

Marine waters from seven sites around Hong Kong with varying levels of sewage pollution were analyzed for Hepatitis A virus (HAV) by PCR cloning and DNA sequencing of the highly variable VP1/2A junction of the HAV genome. Phylogenetic analysis of 10 PCR clones from each of the HAV-positive marine sites indicated that human HAV genotype IB is the most widely distributed type in Hong Kong waters. A sensitive and quantitative TaqMan-based PCR method targeting the 5′-noncoding region (5′-NCR) of HAV was used to quantify HAV particles in marine water samples along with the total Escherichiacoli counts being enumerated on TBX medium for comparison. Our results showed that no correlation of any significance between HAV and E. coli counts was observed which underscores the inadequacy in using E. coli as a sanitary standard to predict the levels of HAV in marine waters.     

On Factors Controlling Air–Water Gas Exchange in a Large Tidal River

Air–water gas exchange is an important process in aquatic systems, including tidal rivers and estuaries. While there are now reliable and routine methods for determining gas exchange over a range of temporal and spatial scales in the ocean and these measurements have resulted in widely used wind speed parameterizations to calculate air–sea gas exchange, the same has not been true for coastal inland waterways. Some studies have suggested that this difference is methodological, while others point to the existence of additional drivers for gas exchange besides wind in rivers and estuaries. Here, we present gas transfer velocities measured in the tidal Hudson River with a method widely used in oceanic studies, the ³He/SF₆ dual tracer technique. Airside and waterside forcings were determined with an anemometer and an acoustic Doppler current profiler, respectively. The results confirm that wind is the dominant driver of gas exchange in the tidal Hudson River, with negligible contribution from bottom-generated turbulence. Furthermore, a parameterization between wind speed and gas exchange developed for the ocean is able to predict gas exchange in this environment with high accuracy. It is hoped that by transferring methodology used in oceanic studies to rivers and estuaries, robust data can be obtained that will eventually allow development of widely applicable relationships between easily measured environmental variables and gas exchange in tidal inland waters.