Kaluza-Klein radiating model in a general scalar-tensor theory

A five dimensional Kaluza-Klein space-time is considered in the presence of prefect fluid source in the general scalar-tensor theory of gravitation proposed by Nordtvedt (Astrophys. J. 161:1069, 1970) with the help of special law of variation for Hubble’s parameter given by Bermann (Nuovo Cimento 74B:182, 1983). A cosmological model with a negative constant deceleration parameter is obtained in this theory. Some physical properties of the model are also discussed.     

Ethnobotanical study towards conservation of medicinal and aromatic plants in upper catchments of Dhauli Ganga in the central Himalaya

The present study broadly focused on medicinal plant species collected from wild by the villagers for different purposes in the upper catchment of Dhauli Ganga in Nanda Devi Biosphere Reserve(NDBR),in the central Himalaya.A schedule based survey was conducted during the years 2003-2005 in 15 villages of Chamoli district part of the NDBR.Information was collected from collectors, vaidya(medicine man)and those dealing with domestication and marketing of the medicinal plants. The aim of the study was to understand the prioritiesed medicinal plants,their mode of collection and document their ethnobotanical uses by the Bhotiya tribal communities,in this world heritage site. During the survey,50 medicinal plants belonging to 31 families and 44 genera were documented.Out of these,70% were harvested from the wild,22% were cultivated and 8% were cultivated as well as wild harvested.Of the cultivated species,8% were found growing in the kitchen gardens and 14%in the agricultural fields.However,42%of the plants had their roots and rhizomes used followed by leaves (26%),seeds(10%),seed and leaf(8%),bark and whole plant(6%)and flower(1%).Most plants were reported to be used for rheumatism(16),followed by stomach disorder(14),cold and cough(11),and jaundice(9).Thirty three plants species were reported to have more than one therapeutic uses,while 17 species were reported to be used against single ailment.The distance of villages from road head was one of the factors contributing to the decline in the medicinal plant population in their natural habitats. The availability of medicinal plants increased with increase in distance from road head and also the peoples’dependence on them.Documentation of the traditional knowledge will help in conservation of knowledge and also opportunity for using it for future training and use.The result of this study will help in promoting sustainable cultivation and implementation in conservation protocol of those species,which are in the verge of extinction in this region.     

Behavior of Marine Clay Subjected to Cyclic Loading with Sustained Shear Stress

Foundations of offshore structures are designed to withstand a combination of static and cyclic loads due to ocean waves. Wave action on offshore structures can cause a significant amount of cyclic horizontal and vertical forces to be transmitted to the soil through the foundation. In all these cases, these cyclic loads are considered to be superimposed over the initial sustained static stress due to the self-weight of structures. This study considers various factors that influence the development of deformation and pore water pressure in a typical cemented marine clay. These results show that the sustained static shear stress significantly influences the strength and deformation behavior of marine clay under cyclic loading. Up to a certain range of sustained static stress, there is an improvement in strength during cyclic loading and the cyclic strains are greatly reduced.     

Observed Variability of Thermohaline Fields,Currents and Eddies in the Western Bay of Bengal During BOBMEX-99

Field measurements during the Bay of Bengal Monsoon Experiment (BOBMEX-99), data from a deep sea moored buoy, and satellite altimeter were used to describe variability in the hydrographic and meso-scale features in the Bay of Bengal (BoB) during the summer monsoon of 1999. The thermohaline fields showed two regions of upsloping of isopleths centered at 82°E and 84.75°E, ～110 km and 450 km away from the coast, respectively, followed by downsloping. The upsloping/downsloping of isopleths and the alternating currents was part of cyclonic and anti-cyclonic circulation patterns in the western BoB. In this region, both wind and current were important in the dynamics of coastal upwelling. The observations showed a relationship between the propagating waves and eddy on variability of thermohaline fields. On an annual cycle, four Kelvin waves were observed in the BoB, but only the downwelling Kelvin wave formed during October entered the Arabian Sea. During the monsoon season, four eddies were formed in the western BoB, of which the anticyclonic eddy centered at 15°N, 84°E and the cyclonic eddy centered at 17.5°N, 84.5°E were prominent. The baroclinic instability caused by the opposing currents along the east coast and the wind stress curl favored the formation of eddies. Okhubo-Weiss and Isern-Fontanet parameter confirmed the presence of eddies in the BoB.     

Millennium recurrence interval of morphogenic earthquakes on the Qingchuan fault,northeastern segment of the Longmen Shan Thrust Belt,China

The 2008 M _w 7.9 Wenchuan produced a ～285–300-km-long coseismic surface rupture zone, including a 60-km-long segment along the Qingchuan fault, the northeastern segment of the Longmen Shan Thrust Belt (LSTB), Sichuan Basin, central China. Field investigations, trench excavations, and radiocarbon dating results reveal that (i) the Qingchuan fault is currently active as a seismogenic fault, along which four morphogenic earthquakes including the 2008 Wenchuan earthquake occurred in the past ca. 3500 years, suggesting an average millennium recurrence interval of morphogenic earthquakes in the late Holocene; (ii) the most recent event prior to the 2008 Wenchuan earthquake took place in the period between AD 1400 and AD 1100; (iii) the penultimate paleoseismic event occurred in the period around 2000 years BP in the Han Dynasty (206 BC–AD 220); (iv) the third paleoseismic event occurred in the period between 900 and 1800 BC; and (v) at least three seismic faulting events occurred in the early Holocene. The present results are comparable with those inferred in the central and southwestern segments of the LSTB within which the Wenchuan magnitude earthquakes occurred in a millennium recurrence interval, that are in contrast with previous estimates of 2000–10,000 years for the recurrence interval of morphogenic earthquakes within the LSTB and thereby necessitating substantial modifications to existing seismic hazard models for the densely populated region at the Sichuan region.     

Determining tidal turbine farm efficiency in the Western Passage using the disc actuator theory

Tidal power potential is determined across the Western Passage in Passamaquoddy Bay using the Finite Volume Community Ocean Model (FVCOM). The tidal turbines are implemented in FVCOM using the disc actuator theory method to determine the power potential for different densities and arrangements of tidal turbines. At the most efficient setting for 10 turbines across the Western Passage, the optimal turbine drag coefficient is 2.0 and the average power output, in a 2-week period, is ～819 kW. Results suggest that for a single row of turbines, the addition of turbines decreases the efficiency of the turbine farm, but this decrease in efficiency is less than 7 %. A parallel distribution of turbines in an array diminishes the average power for turbines in the shadow of other turbines, while staggered distribution in an array increases the average power extraction for some turbines, due to the speed gains in the gaps between turbines. A simple tidal farm optimization using the OpenTidalFarm (OTF) model suggests a similar tidal farm distribution.     

2007年9—11月T213与ECMWF及日本模式中期预报性能检验

2007年9-11月冷空气频繁,气温变幅大,热带气旋活跃,给中期天气预报增加了一定的难度.为积累预报经验,提高中期预报准确率,对9-11月T213模式96小时预报产品进行了天气学检验,并与ECMWF、日本模式进行对比分析.结果表明,T213、ECMWF和日本模式对亚洲中高纬大气环流调整具有较好的中期预报性能,对转折性、灾害性天气的预报有较强指示意义.综合来看,ECMWF对天气系统和要素的预报误差最小,T213模式误差最大,日本模式温度预报性能与ECMWF相当.对0713号台风登陆前的位置和移速,ECMWF预报较为准确,T213模式对台风登陆前移速预报偏慢,对台风登陆后的位置预报偏差最小,日本模式对台风位置和强度预报较为失败.