A submarine-launched wave measuring buoy   总被引：1，自引：0，他引：1  

D. Shonting  F. Middleton  J. Knox  P. Hebda 《Ocean Engineering》1996,23(6):465-481

A wave buoy, the Submarine Deployed Sea State Sensor (SUDSS), was developed to directly measure surface waves from a submerged moving submarine. The SUDSS is adapted from the Submarine Launched Expendable Bathythermograph (SSXBT) by replacing its temperature probe with a vertical sensing accelerometer. The SUDSS, launched from the aft signal ejector, utilizes the SSXBT cylinder, its lifting body, and filament wire spool-out mechanisms. Upon surfacing it oscillates vertically in phase with waves of frequencies below 0.5 Hz producing a voltage signal that is conducted via the filament wire back to the submarine and processed to produce a 10–12 minute wave record. On-board data analysis determines spectra, sea state, and the partial variance of spectral energy which between 0.2–0.5 Hz estimates the local wind speed.An accelerometer calibrator for wave frequencies was assembled consisting of a computer-controlled motor-driven swing arm which rotates an accelerometer as a simple harmonic oscillator; different rotation rates providing a variety of frequencies. Absolute accelerations are determined from the arm radius and its angular velocity. Wilcoxen accelerometers were chosen, providing a linear output of 1 v/g₀ (sensitivity) for simulated waves from 0.09–0.25 Hz (4–11 s periods).The SUDSS fitted with a buoyant tether signal cable, can be deployed from a surface ship for rapid wave/sea state measurements.  相似文献   

CostMAP: an open-source software package for developing cost surfaces using a multi-scale search kernel     

Brendan Hoover  Sean Yaw  Richard Middleton 《International journal of geographical information science》2020,34(3):520-538

ABSTRACT

Cost surfaces are a crucial aspect of route optimization and least cost path (LCP) calculations and are used in awide range of disciplines including computer science, landscape ecology, and energy-infrastructure modeling. Linear features present akey weakness to traditional routing calculations along cost surfaces because they cannot identify whether moving from acell to its adjacent neighbors constitutes crossing alinear barrier (increased cost) or following acorridor (reduced cost). Following and avoiding linear features can drastically change predicted routes. We introduce an approach to address this adjacency issue using asearch kernel that identifies these critical barriers and corridors. We have built this approach into anew Java-based open-source software package– CostMAP (cost surface multi-layer aggregation program)– which calculates cost surfaces and cost networks using the search kernel. CostMAP allows users to input multiple GIS data layers and to set weights and rules for developing aweighted-cost network. We compare CostMAP performance with traditional cost surface approaches and show significant performance gains– both following corridors and avoiding barriers– by modeling the movement of alarge terrestrial animal– the Baird’s Tapir (Tapirus bairdii)– in amovement ecology framework and by modeling pipeline routing for carbon capture and storage (CCS).  相似文献   

Advance of Norway spruce (Picea abies) onto mafic Lommoltunturi fell in Finnish Lapland during the last 200 years     

Raimo Sutinen  Paavo NÄrhi  Maarit Middleton  Pekka HÄnninen  Mauri Timonen  Marja‐Liisa Sutinen 《Boreas: An International Journal of Quaternary Research》2012,41(3):367-378

As a result of global changes, shifts of alpine tree lines towards higher elevations have been recorded, but the role of the spatial variability of the snowpack and zonal‐pattern soil‐nutrient regimes is poorly understood. Norway spruce (Picea abies (L.) Karst) is best suited to fertile soils, and hence we applied soil physical‐chemical and snow measurements and the age chronology of Norway spruce along an elevational gradient (380–557 m a.s.l.) to address a vertical soil zonality hypothesis on mafic Lommoltunturi fell in Finnish Lapland. With regard to increasing elevation, we found an increase in soil N_TOT, C_TOT and Al, but a decrease in soil Ca, Mg and Ca:Al ratio as well as in electrical conductivity (EC). In addition, the snowpack was significantly thicker in low‐elevation forest than in the tree line and open tundra. In the 1840s, spruce established on low‐elevation soils with a Ca:Al ratio of 2.2. Starting from the 1920s a significant shift of spruce occurred such that it took 60 years to expand the tree line by 55 m in elevation. The spruce tree line has advanced, and the age distribution indicates new colonization of spruce in closed forest up to tundra. The poor soil Ca:Al ratio of 0.02 on tundra apparently is a constraint for spruce. Spruce forest is young (<165 years), and hence we argue that spruce has expanded onto formerly tree‐free sites of this mafic fell. This paper demonstrates that vertical soil zonality is a potential driver for the diffuse tree line of Picea abies on mafic Fennoscandian fells.  相似文献   

Editors' note: Astron. Nachr. 1/2010     

Maarit J. Korpi  Anvar Shukurov  Kandaswamy Subramanian 《Astronomische Nachrichten》2010,331(1):4-4

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The subsidence and thermal history of the Bass Basin, Southeastern Australia     

M.F. Middleton 《Tectonophysics》1982,87(1-4)

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Mathematical models of sedimentary processes: edited by Daniel F. Merriam. Plenum Press,New York, 1972, $16.50. 271 pp     

G.V. Middleton 《Geochimica et cosmochimica acta》1975,39(5):773-774

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Electron attachment to interstellar grains     

D. R. Flower  M. J. Middleton 《Monthly notices of the Royal Astronomical Society》2004,352(3):837-840

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Modelling the turbulent magnetized ISM     

Maarit J. Korpi 《Astrophysics and Space Science》2004,289(3-4):449-457

Briefly stated, the interstellar matter (hereafter ISM) is a highlyturbulent flow, the turbulence mainly being driven by the violentstirring by supernova explosions, penetrated by dynamicallysignificant magnetic fields both on small and largescales. Sophisticated numerical models of such a turbulent flow cangive important information on some of the complicated processesoccurring in the ISM, e.g. on the regulation of the observedmultiphase structure, properties of interstellar turbulence and thegeneration and maintenance of magnetic fields by the flow itself; inthis paper such models and their most important results are reviewed.  相似文献   

Ejections of Magnetic Structures Above a Spherical Wedge Driven by a Convective Dynamo with Differential Rotation     

J?rn Warnecke  Petri J. K?pyl?  Maarit J. Mantere  Axel Brandenburg 《Solar physics》2012,280(2):299-319

We combine a convectively driven dynamo in a spherical shell with a nearly isothermal density-stratified cooling layer that mimics some aspects of a stellar corona to study the emergence and ejections of magnetic field structures. This approach is an extension of earlier models, where forced turbulence simulations were employed to generate magnetic fields. A spherical wedge is used which consists of a convection zone and an extended coronal region to ???1.5 times the radius of the sphere. The wedge contains a quarter of the azimuthal extent of the sphere and 150^° in latitude. The magnetic field is self-consistently generated by the turbulent motions due to convection beneath the surface. Magnetic fields are found to emerge at the surface and are ejected to the coronal part of the domain. These ejections occur at irregular intervals and are weaker than in earlier work. We tentatively associate these events with coronal mass ejections on the Sun, even though our model of the solar atmosphere is rather simplistic.  相似文献   

(Re-)negotiating access: The politics of researching skills and knowledge for ‘sustainable communities’     

Julie Newton  Alex Franklin  Jennie Middleton  Terry Marsden 《Geoforum》2012,43(3):585-594

The last decade has witnessed a surge of interest in ‘sustainable communities’ within the UK. This has stimulated a plethora of research aimed at acquiring a better understanding of what ‘sustainable communities’ might look like and how they can be achieved. However, this has not been accompanied by a reflection and interrogation of the actual processes, challenges and politics of doing ‘sustainable communities’ research. This paper addresses this gap by highlighting the importance of paying attention to the on-going process of negotiating access when carrying out sustainability research at the community level. We draw on a recent study of skills and knowledge for ‘sustainable communities’ in Stroud Gloucestershire, UK, to illustrate the importance of sensitivity to social relationships throughout and beyond the research trajectory within sustainability research. Our experience raises important questions about the politics of research practices when doing sustainability research ‘with’ communities and the challenges associated with participatory approaches as a means to demonstrate research impact. We argue that in developing a fuller understanding of why and how different types of community level initiatives can contribute to the ‘sustainable communities’ agenda, greater consideration needs to be given to how these community practices can be better supported through the process of doing academic research.  相似文献