A pilot survey of deepwater coral/sponge assemblages and their susceptibility to fishing/harvest impacts at the Olympic Coast National Marine Sanctuary (OCNMS). Cruise report for NOAA Ship McARTHUR II Cruise AR-04-04: Leg 2 (June 1-12, 2004)

The offshore shelf and canyon habitats of the OCNMS are areas of high primary productivity and biodiversity that support extensive groundfish fisheries. Recent acoustic surveys conducted in these waters have indicated the presence of hard-bottom substrates believed to harbor unique deep-sea coral and sponge assemblages. Such fauna are often associated with shallow tropical waters, however an increasing number of studies around the world have recorded them in deeper, cold-water habitats in both northern and southern latitudes. These habitats are of tremendous value as sites of recruitment for commercially important fishes. Yet, ironically, studies have shown how the gear used in offshore demersal fishing, as well as other commercial operations on the seafloor, can cause severe physical disturbances to resident benthic fauna. Due to their exposed structure, slow growth and recruitment rates, and long life spans, deep-sea corals and sponges may be especially vulnerable to such disturbances, requiring very long periods to recover. Potential effects of fishing and other commercial operations in such critical habitats, and the need to define appropriate strategies for the protection of these resources, have been identified as a high-priority management issue for the sanctuary.

A cohesive approach to thin-shell fracture and fragmentation

We develop a finite-element method for the simulation of dynamic fracture and fragmentation of thin-shells. The shell is spatially discretized with subdivision shell elements and the fracture along the element edges is modeled with a cohesive law. In order to follow the propagation and branching of cracks, subdivision shell elements are pre-fractured ab initio and the crack opening is constrained prior to crack nucleation. This approach allows for shell fracture in an in-plane tearing mode, a shearing mode, or a bending of hinge mode. The good performance of the method is demonstrated through the simulation of petalling failure experiments in aluminum plates. © 2005 Elsevier B.V. All rights reserved.

Effect of size, morphology and crystallinity of seed crystal on the nucleation and growth of single grain Y-Ba-Cu-O

The effect of size, morphology and crystallinity of seed crystals on the nucleation and growth of large grain Y-Ba-Cu-O (YBCO) bulk superconductors fabricated by top seeded melt growth (TSMG) has been investigated. Seeding bulk samples with small, square shaped seed crystals leads to point nucleation and growth of the superconducting YBa2Cu3O7-y (Y-123) phase that exhibits the usual square habitual growth symmetry. The use of triangular and circular shaped seed crystals, however, modifies significantly the growth habit geometry of the grain. The use of large area seeds both increases the rate of epitaxial nucleation of the Y-123 phase and produces relatively large crystals in the incongruent melt, which decreases significantly the processing times of large grain samples. The present study is relevant to decrease processing times of samples with both preferred or no growth sectors and for multiple seeding of large grain samples which contain clean grain boundaries. © 2005 Published by Elsevier Ltd.

Active roll control of an experimental articulated vehicle

A new experimental articulated vehicle with computer-controlled suspensions is used to investigate the benefits of active roll control for heavy vehicles. The mechanical hardware, the instrumentation, and the distributed control architecture are detailed. A simple roll-plane model is developed and validated against experimental data, and used to design a controller based on lateral acceleration feedback. The controller is implemented and tested on the experimental vehicle. By tilting both the tractor drive axle and the trailer inwards, substantial reductions in normalized lateral load transfer are obtained, both in steady state and transient conditions. Power requirements are also considered. © IMechE 2005.

Large single grain (RE)-Ba-Cu-O superconductors with nano-phase inclusions

Nano-phase (5-20 nm) particles of YBa2(Cu0.5M 0.6)O6 [where M = Nb, Ta, Mo, W, Zr and Hf] have been introduced successfully into RE-Ba-Cu-O single grain superconductors. A study to enlarge the size of a single grain containing these particles has been carried out involving measurement of the growth rate as a function of YBa 2(Cu0.5M0.6)O6 phase concentration and degree of un-dercooling. The influence of the change in YBa2 (Cu0.8M0.5)O6 concentration on microstructural features is also investigated and the superconducting properties of these large grain superconductors are presented. © 2005 IEEE.

Axial stiffness of journal bearings in zero-field and field-cooled modes

Superconducting journal bearings have been investigated for use in flywheel systems. We report on the zero-field cooled and field-cooled stiffness of these bearings. They are made up of radial magnet rings with alternating polarities, a pole pitch of 11 mm and a surface field of 0.1 T. Field-cooled stiffness of the journal bearings increased four times over the zero-field-cooled stiffness. © 2005 IEEE.

Superconducting micro-bearings

This paper presents research into superconducting Micro-Bearings for MEMS systems. Advanced silicon processing techniques developed for the Very Large Scale Integration (VLSI) industry have been exploited in recent years to enable the production of micro-engineered moving mechanical systems. These devices commonly known as Micro-ElectroMechanical Systems (MEMS) have many potential advantages. In many respects the effect of scaling a machine from macro-sized to micro-sized are either neutral or beneficial. However in one important respect the scaling produces a severely detrimental effect. That respect is in the tribology and the subsequent wear on the high speed rotating machines. This leads to very short device lifetimes. This paper presents results obtained from a MEMS motor supported on superconducting bearings. The bearings are self-positioning, relying on, the Meissner effect to provide a levitation force which moves the rotor into position and flux pinning to provide stability thereafter. The rotor is driven by a simple electrostatic type motor in which photo resist is used to pattern the motor poles directly onto the rotor. © 2005 IEEE.

Grain boundaries in multi-seeded melt-grown superconductors

Future applications of high temperature superconductors require bulk materials of a complex shape. The multi-seeded-melt-growth process (MSMG) represents a promising technique for obtaining qualitatively well oriented bulk materials with different kinds of shape. In the MSMG process, several seeds are placed on a precursor pellet, from which the growth of the bulk starts. A certain problem of the MSMG process is that grain boundaries become inevitable when the growth fronts of two neighboring seeds collide. These grain boundaries are responsible for a reduction of the critical currents and pose a problem for high current applications. By polishing the sample step by step, the influence of the grain boundaries was investigated by scanning Hall probe measurements and by the magnetoscan technique. Additionally, optical microscopy and electron microscopy were employed to investigate the details of the microstructure. © 2005 IEEE.

高压大电流同轴结构无电感闸流管油箱

本实用新型主要涉及一种高压大电流闸流管油箱的结构。一种高压大电流同轴结构无电感闸流管油箱，包括有油箱（１），闸流管附件（４），其主要特点是还包括有在油箱（１）内设有闸流管（２），在闸流管（２）的外侧同轴设有绝缘筒（８）和外导体筒（３）；绝缘筒（８）固连于电缆接头的绝缘套（５２）；外导体筒（３）固连于套管（５３），电缆接头的套管（５３）固连于固定板（７）；在电缆接头固定板（７）上设有多个与闸流管同轴方向设置的电缆接头（５），电缆接头（５）的出线端固连有电流汇流板（６），其上设有Ｕ形接头（６１）连接于闸流管（２）的高压引入端和／或高压引出端。本实用新型的优点是闸流管是采用同轴结构设计，其连接安全可靠，杂散电感极低，特别适用于高压大脉冲电流、低电感要求的精密电路。

高压大电流电缆同轴接头

本实用新型主要涉及一种电缆同轴接头的结构。一种高压大电流电缆同轴接头，包括有电缆（１０），其主要特点是还包括有在电缆的接头端设有绝缘连接套（５），其一端的内孔套于内绝缘层（１２）的外部，另一端的内孔镶嵌有导电输出轴（７），电缆内导体（１１）紧固于导电输出轴（７）的接管内。本实用新型的有益效果是，电缆接头采用同轴、整体结构，其独特的电气连结方式，包括有内导体和外导体两部分的连接，以及内外导体之间的绝缘。其耐压高，连接可靠，整个接头杂散电感低，接触电阻小，可普遍用于各种规格高压同轴电缆与其它元件的连接。尤其适用于高压大脉冲电流的精密同轴结构中。

直流电源远程控制器

本实用新型涉及一种基于８位单片机的电源远程控制器，在主控计算机的控制下，实现对高精度高稳定度直流稳流电源或稳压电源的远程控制和远程测试。一种直流电源远程控制器，包括有单片机（１），单片机（１）的地址总线（１０）连接地址译码器（３）和数据储存器（４），其特征是还包括有地址译码器（３）的译码输出端分别作为数据储存器（４）、数模转换电路（５）、模数转换电路（６）、状态量输入电路（７）和开关量输出电路（８）的选通地址；单片机（１）的８位数据总线（９）分别连接数据储存器（４）、数模转换电路（５）、模数转换电路（６）、状态量输入电路（７）、开关量输出电路（８）；单片机（１）的串行口与通信接口电路（２）连接。本实用新型实现了对高精度高稳定度直流稳流或稳压电源的远程分布控制。控制数据通信可靠，控制命令响应正确，具有良好的抗干扰能力；远控基准长期稳定度高。

高精度直流电源远程控制器

本发明涉及一种基于８位单片机的电源远程控制器。一种高精度直流电源远程控制器，包括有单片机（１），单片机（１）的地址总线（１０）连接地址译码器（３）和数据储存器（４），其主要特点是还包括有地址译码器（３）的译码输出端分别作为数据储存器（４）、数模转换电路（５）、多路独立模数转换电路（６）、状态量输入电路（７）和开关量输出电路（８）的片选地址；单片机（１）的８位数据总线（９）分别连接数据储存器（４）、数模转换电路（５）、多路独立模数转换电路（６）、状态量输入电路（７）、开关量输出电路（８）；单片机（１）的串行口与通信接口电路（２）连接。本发明的优点是实现了对高精度高稳定度直流稳流或稳压电源的远程分布控制。各功能模块运行稳定，开发不同的控制软件，达到相应的控制目的；控制数据通信可靠，控制命令响应正确，具有良好的抗干扰能力；远控基准长期稳定度高。