Biotic communities of freshwater marshes and mangroves in relation to saltwater incursions: implications for wetland regulation

An ecosystem-level study was conducted in the Guandu wetlands in subtropical coastal Taiwan to examine how salinity influences the abundance, diversity, and structure of biotic communities. We surveyed eight permanent study sites, spanning freshwater marshes, to the gate on the dyke, and mesohaline mangroves representing a gradient of the extent of saltwater incursions. Analyses of abiotic variables showed that salinity was the primary determining factor for discriminating habitat types in the wetlands, but communities differed in their sensitivity to salinity. The composition of plant and insect communities was most affected by the salinity gradient, suggesting the utility of these communities for ecological monitoring of saltwater incursions. However, spatial changes in communities at higher trophic levels, including macrobenthos, mollusks, fish, and birds, could not be explained simply by the salinity gradient. Instead, changes in these communities were more relevant to the composition of other biotic communities. Our results show that species richness and diversity of plant communities were higher in the marshes than in the mangroves. Nevertheless, insect communities censused in the mangroves had higher diversity, despite lower abundance and species richness. Macrobenthos surveyed in the mangroves showed higher biomass and number of taxa. Mollusks and fish were also more abundant at sites near the gate compared to the marsh sites. This suggests that maintaining a tidal flux by means of gate regulation is necessary for conserving the spatial heterogeneity and biodiversity of coastal wetlands

Identification of alpha-enolase as an autoantigen in lung cancer: Its overexpression is associated with clinical outcomes

Purpose: Although existence of humoral immunity has been previously shown in malignant pleural effusions, only a limited number of immunogenic tumor-associated antigens (TAA) have been identified and associated with lung cancer. In this study, we intended to identify more TAAs in pleural effusion-derived tumor cells. Experimental Design: Using morphologically normal lung tissues as a control lysate in Western blotting analyses, 54 tumor samples were screened with autologous effusion antibodies. Biochemical purification and mass spectrometric identification of TAAs were done using established effusion tumor cell lines as antigen sources. We identified a p48 antigen as of-enolase (ENO1). Semiquantitative immunohistochemistry was used to evaluate expression status of ENO1 in the tissue samples of 80 patients with non-small cell lung cancer (NSCLC) and then correlated with clinical variables. Results: Using ENO1-specifc antiserum, up-regulation of ENO1 expression in effusion tumor cells from 11 of 17 patients was clearly observed compared with human normal lung primary epithelial and non-cancer-associated effusion cells. Immunohistochemical studies consistently showed high level of ENO1 expression in all the tumors we have examined thus far. Log-rank and Cox's analyses of ENO1 expression status revealed that its expression level in primary tumors was a key factor contributing to overall- and progression-free survivals of patients (P < 0.05). The same result was also obtained in the early stage of NSCLC patients, showing that tumors expressing relatively higher ENO1 level were tightly correlated with poorer survival outcomes. Conclusions: Our data strongly support a prognostic role of ENO1 in determining tumor malignancy of patients with NSCLC

High Current Transmission and Switching System for a Prototype, 20 Tesla, Toroidal Magnet

The Ignition Technology Demonstration (ITD) is a 0.06 scale prototype toroidal field magnet of the proposed full-scale IGNITEX (Ignition Experiment) tokamak. The goal of ITD is to achieve an on-axis magnetic confinement field of 20 T while demonstrating the magnet's ability to withstand high magnetic and thermal stresses [1,2]. To accomplish this task, a peak current of 9 MA must be transferred from six balanced homopolar generator (HPG)/busbar circuits to the liquid nitrogen (LN2) cooled magnet. HPGs are well suited for operation of single-turn coils because they are inherently high current, low voltage machines which can inertially store the energy required for a pulsed discharge. To date the system has delivered pulses of up to 8.14 MA to the toroidal magnet, producing an onaxis field of 18.1 T. In order to properly synchronize current transfer, an explosive closing switch is employed for each of the six independent HPG/busbar circuits. The switches operate by explosively driving a scalloped copper ring into a tapered annular gap made up of two copper alloy rings. With a jitter time of 10 μs, parallel circuit synchronization is better than 0.03% relative to the current rise time. The excellent performance of the switches during discharges of up to 8.14 MA is attributed to several design features which assure proper current distribution. Busbar design considerations have included electromagnetic loading, thermal gradients and magnet preloading effects. The switches and busbars have successfully operated at 82% of their rated action of 1.24 x 1011A2s per switch. Description of the ITD busbar/switching system, design improvements, and operational experience are presented.Center for Electromechanic

Advanced Compulsators for Railguns

In order to maximize the penetration of a projectile into a target, the acceleration on the projectile during the launch must be minimized. Low accelerations permit the design of long and slender projectiles which have better penetration capability. From this standpoint, power supplies for electromagnetic launchers must be able to provide rectangular current pulses with a high average to peak acceleration ratio. The authors discuss efforts to obtain the desired pulse shape from a compensated pulsed alternator (compulsator) when it is used as a power supply for railguns. A general theory of the pulse shaping technique is presented first. This is followed by a discussion on the tradeoffs between various equivalent generator configurations. Finally, the electromagnetic design of the compensated pulsed alternator being developed for task C of the Electromagnetic Gun Weapons System Program is presentedCenter for Electromechanic

InGaN light emitting solar cells with a roughened N-face GaN surface through a laser decomposition process

InGaN-based light-emitting solar cell (LESC) structure with an inverted pyramidal structure at GaN/sapphire interface was fabricated through a laser decomposition process and a wet crystallographic etching process. The highest light output power of the laser-treated LESC structure, with a 56% backside roughened-area ratio, had a 75% enhancement compared to the conventional device at a 20 mA operating current. By increasing the backside roughened area, the cutoff wavelength of the transmittance spectra and the wavelength of the peak photovoltaic efficiency had a redshift phenomenon that could be caused by increasing the light absorption at InGaN active layer. (C) 2010 Optical Society of Americ

A trophic model for the Danshuei River Estuary, a hypoxic estuary in northern Taiwan

The estuary of the Danshuei River, a hypoxic subtropical estuary, receives a high rate of untreated sewage effluent. The Ecopath with Ecosim software system was used to construct a mass-balanced trophic model for the estuary, and network analysis was used to characterize the structure and matter flow in the food web. The estuary model was comprised of 16 compartments, and the trophic levels varied from 1.0 for primary producers and detritus to 3.0 for carnivorous and piscivorous fishes. The large organic nutrient loading from the upper reaches has resulted in detritivory being more important than herbivory in the food web. The food-chain length of the estuary was relatively short when compared with other tropical/subtropical coastal systems. The shortness of food-chain length in the estuary could be attributed to the low biomass of the top predators. Consequently, the trophic efficiencies declined sharply for higher trophic levels due to low fractions of flows to the top predators and then high fractions to detritus. The low biomass of the top predators in the estuary was likely subject to over-exploitation and/or hypoxic water. Summation of individual rate measurements for primary production and respiration yielded an estimate of -1791 g WW m(-2) year(-1), or -95 g C m(-2) year(-1), suggesting a heterotrophic ecosystem, which implies that more organic matter was consumed than was produced in the estuary. (C) 2007 Elsevier Ltd. All rights reserved

Demonstration of a Prototype, High Field, Single Turn, Toroidal-Magnet System

Very high toroidal magnetic fields have been produced using a single-turn magnet powered by homopolar generators (HPGs). A design goal of a 20 tesla confinement field has been met by the combination of a low impedance toroidal magnet, a high current, low voltage power supply, and the use of a high strength, high conductivity copper alloy. The Ignition Technology Demonstration (ITD) is a 1/16 scale prototype of the proposed full-scale IGNITEX (Ignition Experiment) toroidal field (TF) magnet. Stresses and temperatures reached in the prototype TF magnet are representative of those that would be experienced in a 1.5-m major radius magnet with a 5 s flat top current profile. Synchronized, parallel operation of multiple homopolar generators into a single-turn toroidal magnet has been realized. The prototype TF magnet has produced toroidal magnetic fields up to 18.1 T on-axis with liquid nitrogen (LN2) precooling and axial preloading of the magnet. Room temperature operation of the magnet has produced on-axis fields up to 11.5 T and with LN2 precooling only, up to 15.4 T. Peak current from the HPG system for the 18.1 T test was 8.14 MA with an open circuit voltage of only 49 V. Generator synchronization is achieved by six, 1.5 MA rated, closing switches with a maximum jitter of 10 μs. A peak current density in the inner leg region of the TF magnet of 750 MA/m2 was experienced during the 18.1 T test. Peak temperature in the inner leg region for this test was measured to be 135°C. The description of the ITD experiment, operational experience, and test results are presented.Center for Electromechanic

Magnetic System for the Ignitex Fusion Ignition Experiment

Controlled D-T fusion in a tokamak device by ohmic heating alone can be realized with toroidal confinement fields between 15 and 20 T and plasma currents in the 12- to 15-MA range. These conditions are achieved in the IGNITEX concept [1,2) by using a single turn toroidal field coil designed for 20-T operation and a set of five, single turn poloidal field coil pairs located within the plasma bore of the 1.5 m major radius machine (0.5 m minor radius). Total pulse length for the experiment is 10 s, including a 5 s flat-top period. A single-turn configuration for the toroidal field coil was adopted to maximize load-carrying ability and virtually eliminate insulation problems. Peak current for 20-T operation is 150 MA which results in an average inner leg current density of 57 MA/m2, a relatively low value for the field produced. Support of the toroidal field coil includes axial preloading of the inner leg to a 469 MPa compressive stress with an externa 1 hydraulic press structure, a 234 MPa radial compressive preload applied at the top and bottom of the coil by two thermally fitted steel rings, and a 0.8 m diameter compression bar located in the coil central bore. The coil itself is housed in a cryostat for precooling to liquid nitrogen temperature to extend the usable temperature excursion. Time dependent finite element analysis of the single-turn coil indicates that a maximum von Mises stress of 531 MPa will occur in the inner leg region. The analysis also includes time evolution of temperature and current distribution within the coil as well as calculation of energy requirements. Peak temperature after the 10-s pulse will be less than 100°c. A dispersion strengthened copper alloy has been selected as the toroidal coil material for its excel lent combination of yield strength and conductivity, which are 582 MPa and 92% IACS, respectively. The material exhibits a high fatigue limit of 207 MPa. To demonstrate the operation of the single-turn coil at the 20-T level, a 1/6th scaled prototype is proposed using an existing 60 MJ, 9 MA six module hompolar generator (HPG) power supply located at the Center for Electromechanics at The University of Texas at Austin (CEM-UT).Center for Electromechanic

Electromechanical and Thermomechanical Stress Analysis of the Toroidal Field Magnet System in Single Turn Ignition Tokamaks

The Texas fusion ignition experiment (IGNITEX) device is a 20 T single turn coil tokamak designed to produce and control an ignited plasma using ohmic heating alone. As a baseline design, IGNITEX has a 1.5 m major radius and operates at a toroidal field (TF) of 20 T on-axis. The small version of IGNITEX (R = 1.2 m) represents the smallest, low cost experiment that can produce fusion ignition under the saturated Neo-Alcator energy confinement scaling. The large version of IGNITEX (R = 2.1 m) represents the smallest experiment that can produce fusion ignition using the most pessimistic extrapolation of the Goldston scaling in L-mode. The Ignition Technology Demonstration (ITD) program was initiated to design, build, and test the operation of a single turn, 20 T, TF coil powered by an existing 9 MA, HPG power supply system. The ITD TF coil is a 0.06 scale of the IGNITEX and is now operating at the Center for Electromechanics at The University of Texas at Austin (CEM-UT). Data from the ITD experiment is used to confirm the complex computer model utilized for the IGNITEX design and analysis. In this paper, feasibility of the TF magnets is evaluated based on the electromechanical and thermomechanical considerations.Center for Electromechanic

High-Current Busbars for a Prototype Homopolar-Toroidal Magnet System for Fusion Ignition

The Ignition Technology Demonstration (ITD) is a full torus, scaled prototype of the 20 T toroidal field (TF) coil of the proposed fusion ignition experiment IGNITEX. The 0.06 scale in linear dimension is based on the linear relation between the peak current of an existing power supply (9 MA) and the current required to produce a 20 T field in the fullscale machine (150 MA). Presented here are the design and performance of a busbar and switch which have successfully transferred a total current of 6.75 MA to the ITD during a 15 T experiment. Design considerations included thermal and electromechanical stresses, material properties in liquid nitrogen, electrical resistance and inductance, and physical integration with the existing power supply. The ITD is driven by a 60 MJ, 9 MA power supply consisting of six 1.5 MA homopolar generators (HPGs) located in the Center for Electromechanics at The University of Texas at Austin (CEM-UT).Center for Electromechanic