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No description available.

In this study, concentrations of organic biomarkers of core MD012404, recovered from central part of the Okinawa Trough, were analyzed, included of unsaturated alkenones and n-alkanes, for reconstructing paleoenviromental and paleoclimatic records for the past 100,000 years. The unsaturated alkenone index of Uk¡¬37 were calculated for reconstructing past variations of sea surface temperature (SST) in the East Chna Sea (ECS). Through the past 100,000 years, our record revealed that the varied pattern of paleo-SSTs of the ECS was mainly reflecting Interglacial/Glacial cycles. This result indicates that the enhanced East Asian winter monsoon which is induced by the changing orbital forcing is the dominant controlling factor to influence the hydrological conditions in the ECS. Otherwise, except of the warming event of Bølling-Allerød and cooling event of Younger Dryas, no obviously cooling trends were observed in the record indicating that the Uk¡¬37 based SST was not sensitive to the millennial-scaled climate events. This may be caused by the slow response of the SST to the millennial-sclaed events. The concentrations of unsaturated alkenones reconstructed in this study can represent to the surface productivity of the ECS. Our record shows that the values are higher in glacial period than in interglacial period. The higher productivity observed in glacial period may result from the wind-driven water mixing. Therefore, the well-mixing of surface and subsurface water thus can supply higher nutrients upto the surface water than induce the higher productivity in glacial period in the ECS. However, a more complicated pattern is found in MIS 5, the unsaturated alkenones have extremely high values in this interval which is different to the Holocene even though that the climatic conditions and global sea level are similar in these two periods. These high values may be caused by either higher surface production or well preservation, which results from the pool ventilation in the ECS. In addition, distributed pattern of n-alkanes can represent to the possible sources of organic materials and vegetation changes on land. Our record shows that n-C31 alkane is dominant in n-alkanes, and the distribution pattern of n-alkanes (C31 > C29 > C33 > C27 > C25 ) is similar to the sediments discovered on the continental shelf of ECS and the estuary of the Changjiang River and is different with the sediments from the Lanyang Hsi River. This fact indicates that the organic materials buried in sediments of the Okinawa Trough are mainly contribute from the ECS continental shelf and the Changjiang River is serves as the main contributor of terrestrial sediments in the study region. Our calculated Carbon preference index (CPI) indicates that terrigenous orangic matters are less influenced by degradation and diagenesis in glacial period, especially during LGM, and the changing pattern is highly correlated with the global sea level changes. Lower sea level observed in glacial period shorten the transporting distance of sediments from the Changjiang River to the Okinawa Trough thus causes more terrestrial inputs and deposits in the Okinawa Trough.

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The purpose of this thesis is to describe the preliminary results from the investigation of shallow (<20m) hydrothermal vents with a total venting area of about 0.5 km2 off the eastern tip of Kueishantao Island. The chemical compositions of hot fluids, sediments and rocks as well as a continuous record of fluid temperature of a fumarole were measured in order to understand the venting process of hydrothermal fluids. The continuous temperature records show that the attainment of the maximum temperature of the hot fluids is related to the tidal cycle. The temperature variation seems to be associated with changes in the boiling point of seawater, which is affected by changes in water pressure. Such a correlation has not been reported in the literature. The hydrothermal fluids reach their highest temperature about 3.5 hours after each high tide, which is indicative of a shallow infiltration of seawater since the time it takes the boiling seawater to exit is so short. The hottest temperature recorded in our study area is 116¢J, while the lowest pH is 1.75, both a record in the world amid shallow hydrothermal systems. And, 1.75 is the lowest pH been reported on hydrothermal systems in the literature. At one point, the temperature recorder was covered with sand as a result of an encroaching typhoon. This suggests that the topography of the study area is susceptible to external forces. Based on salinity, the source of the hot fluids is taken to be ambient seawater, with no meteoric water from the islet involved. Concentrations of major ions in the hydrothermal fluids are almost the same as those in the ambient seawater. Mg is slightly enriched, however, which is unlike other hydrothermal fluids where, as reported elsewhere, Mg is generally lower because it replaces Ca in the bedrock. Low concentrations of Si in the studied fluids make for another distinct feature. Compared with other hydrothermal fluids in the world, the concentrations of Si in our study area are much lower, possibly on account of there being insufficient time for the rock to dissolve in the infiltrated seawater. Black and white smokers have widely been reported in the literature, but here are found heretofore unheard of yellow smokers as high as 6 meters. Other than one vent which emits liquid sulfur and forms a sulfur chimney, some vent sulfur from sulfur mounds. Still others are low- temperature vents which do not emit sulfur whatsoever. The most active venting activities are off the eastern tip of the islet. There are no other large reliefs associated with the hydrothermal activity, except for the chimney and a depression down to 35m deep. the chimney and a depression down to 35m deep. The composition of gravel on the seafloor is andesite, which is the same as the rock on the islet. The major composition of the sediments collected from the seafloor is sulfur, which is different from the sediments of the hydrothermal systems in the Okinawa Trough. The sulfur particles observed in this study originate from the fumaroles. Besides, sulfur balls the size of softballs and with distinct growth rings are found near some vents. The formation mechanism of these rings at this time, however, remains unclear. The bubbles from the vents are mostly made up of CO2, which is different from the composition of the shallow hot springs on the beach of Green islet. The 3He/4He of the emitted gas is high, this indicates that the gas may have originated from the mantle.

<p> A syncline-anticline pair in miogeosynclinal sediments of the western margin of the Labrador Trough was mapped. Samples were taken of each rock unit and a structural analysis was performed. The structure determined was compared in an elementary fashion to geophysics completed over the mapping area. </p> <p> The folds in the pair are highly variable along their length changing from an open to tight folding style and with a rolling plunge varying from 3° NW to 12° SE. </p> <p> The beds of the folds show no internal deformation except for drag folding in the shaly units. The rocks were folded by a flexural slip mechanism. </p> <p> The gravity and ground magnetics successfully outlined the structure of the fold, dipping of the beds and in one instance located a fault. Typical gravity values (signatures) for a number of rock units are easily determined.</p> / Thesis / Bachelor of Science (BSc)

Trough waveguides (TWG) have been utilized in a variety of radio frequency (RF) and other related applications including radar, the treatment of hypothermia and in the generation of plasmas. Perturbing the guided wave in these structures with blocks, rods, dielectrics, and other structures can create reconfigurable periodic line sources. These trough waveguide antennas (TWA) are then capable of providing both fixedfrequency and frequency-dependent beam steering. This was originally performed using electro-mechanical “cam-and-gear” mechanisms. Previous work related to the excitation of TWG and the performance of TWA topologies are limited when compared to more common antenna designs, yet they possess many desirable features that can be exploited in a modern system. This thesis will examines an S-band rectangular-to-trough waveguide transition and trough guide antenna that has been designed for broadband reconfigurable antenna applications considering as well the airflow characteristics for sensing applications. The design, fabrication, and electromagnetic performance (mode conversion, impedance matching, and antenna performance) are discussed, including the use of metallic cantilever perturbations placed along the troughguide sidewalls that are designed to provide improved impedance matching when steering the beam from the backward quadrant through broadside, towards the forward quadrant. Impedance matching techniques such as use of circular holes at the edge of each actuated cantilever are used to reduce power reflections and provide a low voltage standing wave ratio (VSWR) along the S-band. Finite element simulations will provide a demonstration of the airflow and turbulence characteristics throughout the entire structure, where the metallic cantilevers are used to manipulate the flow of air, to distribute it across the surfaces of the structure better and improve its potential for sensing operations.

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No description available.

HAWE Hydraulic SE, Munich, engineers and manufactures hydraulic drives (CSP-drives) for parabolic trough plants consisting of a compact power pack, directional and control valves, over-center valves, two cylinders and the fittings/hoses for connecting these components. Optional, but this is depending on the system and the control philosophy, also a hydralic accumulator. An optimized hydraulic drive for a parabolic trough field makes the power plant operator profit from savings at components, higher system efficiency, lower operational energy supply needs, less time spent on commissioning and first start-up, lower maintenance effort and increased life span of the drive and finally also savings on peripheral and safety devices. Many of shown proposals are even combining two or more of above mentioned advantages.