A novel trigger-based method for hydrothermal vents prospecting using an autonomous underwater robot

In this paper we address the problem of localizing active hydrothermal vents on the seafloor using an Autonomous Underwater Vehicle (AUV). The plumes emitted by hydrothermal vents are the result of thermal and chemical inputs from submarine hot spring systems into the overlying ocean. The Woods Hole Oceanographic Institution’s Autonomous Benthic Explorer (ABE) AUV has successfully localized previously undiscovered hydrothermal vent fields in several recent vent prospecting expeditions. These expeditions utilized the AUV for a three-stage, nested survey strategy approach (German et al. in Deep Sea Res. I 55:203–219, 2008). Each stage consists of a survey flown at successively deeper depths through easier to detect but spatially more constrained vent fluids. Ideally this sequence of surveys culminates in photographic evidence of the vent fields themselves. In this work we introduce a new adaptive strategy for an AUV’s movement during the first, highest-altitude survey: the AUV initially moves along pre-designed tracklines but certain conditions can trigger an adaptive movement that is likely to acquire additional high value data for vent localization. The trigger threshold is changed during the mission, adapting the method to the different survey profiles the robot may find. The proposed algorithm is vetted on data from previous ABE missions and measures of efficiency presented.     

Study of PBL dynamics over northern plains in fixing stack height of a super thermal power station

The Planetary Boundary Layer plays an important role in air pollution meteorology and in fixing the Stack height of major air-polluting industries, including the super thermal power plants. In India a super thermal power plant is being set up at Yamunanagar (30·1° N, 77·33 ° E) and it has been studied using an acoustic sounder with a stack height of 220?m which would be the optimum height to keep the physical stack above surface based inversions for 80 per cent of the time and the elevated inversions for 50 per cent of time above. However, the hot plume rise would inject any pollutants above the surface based inversions for 95 per cent of the time     

Attitude analysis on the sunken Samho Brother vessel

In October 2005, the Samho Brother, a 90 m long chemical tanker ship, sank 74 m deep in the Taiwan Strait off the Hsinchu coast. The ship was transporting benzene and marine fuel. In April 2009, an attitude survey of the sunken ship was conducted to prevent further environmental damage that may arise from chemical spillage. The survey used multi-beam echo sounders and side-scan sonar systems. However, attitude estimations using multi-beam data only gave the vessel's laying angle, with large variations, at around 14° roll direction. This value was suspicious because 1.5° footprints of multi-beam echoes were too large for deep and acoustic waves that could easily bounce on the wreckage. With detailed mapping using the side-scan sonar approach, different sonographs of the sunken vessel were obtained from different scanning attitudes and angles standing more than 10 m above the seafloor. In this study, an estimation of target heights was demonstrated to determine the correct procedures in handling side-scan sonar schemes. It is proposed that the Samho Brother had transversely rotated; its port was at an upward position relative to its side, which was lying on the seafloor. It lies horizontally along the keel direction, but the surface of the hold (deck) level is tilted 18° vertically to the west.     

Developing clear-sky,cloud and cloud shadow mask for producing clear-sky composites at 250-meter spatial resolution for the seven MODIS land bands over Canada and North America

A new technology was developed at the Canada Centre for Remote Sensing (CCRS) for generating Canada-wide and North America continental scale clear-sky composites at 250 m spatial resolution for all seven MODIS land spectral bands (B1–B7). The MODIS Level 1B (MOD02) swath level data are used as input to circumvent the problems with image distortion in the mid latitude and polar regions inherent to the global sinusoidal (SIN) projection utilized for the standard MODIS data products. The MODIS 500 m land bands B3 to B7 are first downscaled to 250 m resolution using an adaptive regression and normalization scheme for compatibility with the 250 m bands B1 and B2. A new method has been developed to produce the mask of clear-sky, cloud and cloud shadow at 250 m resolution. It shows substantial advantages in comparison with the MODIS 250 m standard cloud masks. The testing of new cloud mask showed that it is in reasonable agreement with the MODIS 1-km standard product once it is aggregated to 1-km scale, while the cloud shadow detection looks more reliable with the new methodology. Nevertheless, more quantitative analyses of the presented scene identification technique are required to understand its performance over the range of input scenes in various seasons. The new clear-sky compositing scheme employs a scene-dependent decision matrix. It is demonstrated that this new scheme provides better results than any others based on a single compositing criterion, such as maximum NDVI or minimum visible reflectance. To account for surface bi-directional properties, two clear-sky composites for the same time period are produced by separating backward scattering and forward scattering geometries, which separate pixels with the sun-satellite relative azimuth angles within 90°–270° and outside of this range. Comparison with Landsat imagery and with MODIS standard composite products demonstrated the advantage of the new technique for screening cloud and cloud shadow, and generating high spatial resolution MODIS clear-sky composites. The new data products are mapped in the Lambert Conformal Conic (LCC) projection for Canada and the Lambert Azimuthal Equal-Area (LAEA) projection for North America. Presently this activity is limited to MODIS/TERRA due to known problems with band-to-band registration and noisy SWIR channels on MODIS/AQUA.     

Inter-comparison of wind profiles in the tropical boundary layer remotely sensed from GPS radiosonde and Doppler wind lidar

Winds play a very important role in the dynamics of the lower atmosphere, and there is a need to obtain vertical distribution of winds at high spatio-temporal resolution for various observational and modelling applications. Profiles of wind speed and direction obtained at two tropical Indian stations using a Doppler wind lidar during the Indian southwest monsoon season were inter-compared with those obtained simultaneously from GPS upper-air sounding (radiosonde). Mean wind speeds at Mahbubnagar (16.73° N, 77.98° E, 445 m above mean sea level) compare well in magnitude for the entire height range from 100 m to 2000 m. The mean difference in wind speed between the two techniques ranged from ?0.81 m s^?1 to +0.41 m s^?1, and the standard deviation of wind speed differences ranged between 1.03 m s^?1 and 1.95 m s^?1. Wind direction by both techniques compared well up to about 1200 m height and then deviated slightly from each other at heights above, with a standard deviation in difference of 19°–48°. At Pune (18^○32′ N, 73^○51′ E, 559 m above mean sea level), wind speed by both techniques matched well throughout the altitude range, but with a constant difference of about 1 m s^?1. The root mean square deviation in wind speed ranged from 1.0 to 1.6 m s^?1 and that in wind direction from 20° to 45°. The bias and spread in both wind speed and direction for the two stations were computed and are discussed. The study shows that the inter-comparison of wind profiles obtained by the two independent techniques is very good under conditions of low wind speeds, and they show larger deviation when wind speeds are large, probably due the drift of the radiosonde balloon away from the location.     

Micro liquid rotor operated by surface-acoustic-wave

A micro liquid rotor operated by surface acoustic waves (SAWs) was proposed and fabricated. The liquid rotor has two interdigital transducers (IDTs) that generate SAWs, in order to increase efficiency of rotating the liquid. The IDTs were fabricated by patterning Al/Cr on a LiNbO₃ substrate. Moreover, the liquid rotor has a cylindrical liquid pool of 4 mm diameter and 200 μm depth. A sidewall of the liquid pool was made of epoxy-based negative photoresist on the substrate. As characteristics of the liquid rotor, we investigated relationships between electric power applied to the IDTs and angular velocity of the liquid or its temperature. Through experimentation, it was shown that the angular velocity and the temperature increase with increasing the electric power. When the fabricated liquid rotor was applied electric power of 2 W, the liquid of 5 μL rotated at 330 rad/s (3,100 rpm) and its temperature reached 65°C.     

The 7 September 1999 Athens 5.9 Ms earthquake: Remote sensing and digital elevation model inputs towards identifying the seismic fault

The meisoseismal area of the (Ms = 5.9) earthquake of 7 September 1999 in Athens, Greece was localized in the western suburbs of the city (38.1° N, 23.7°E) where no active faulting had been mapped before. Here we show that remote sensing can provide conclusive evidence for the identification of seismogenic structure. Methods applied were: interpretation of Landsat TM images, digital overlays of field observations and aftershock distribution patterns, construction of a 20-m DEM and application of shading techniques, and comparison with fault plane solutions and dominant slip direction in striation populations. Our results imply that the earthquake source is located within the NW-SE trending valley in the Fili region across the south foothills of Mt Parnitha. The earthquake occurred along a normal fault with 110°N-130°N strike, which exhibits typical morphotectonic features of an active fault.     

Cloud detection and classification over oceans at night with NOAA-7

Clouds above the ocean are detected with three thermal-infrared channels of the AVHRR on board NOAA-7. A classification into low, middle and high clouds is possible. As only spectral and not spatial information is used, it is possible to analyse each pixel individually. The classification has been developed with a radiative transfer model for clouds adapted to the spectral domain of the NOAA-7 infrared channels. The ruling parameter is the ratio between scattering and extinction. The spectral optical depth has slightly less influence, while different anisotrophy of scattering for individual types of clouds is not important. Two parameters are best suited to classifying clouds, namely, brightness temperature in channel 5(12·0 μm) and the difference of brightness temperature between channel 3 (3·7μm) and channel 4 (10·8 μm). The algorithm to classify clouds with thresholds referring to the standard atmosphere ‘autumn 45° north’ is applied to actual satellite data.     

The Effect of Posture on the Running Speed of Skiing

Abstract

These experiments were performed at the Syowa Station in Antarctica (69°00'S, 39° 35'E) where a straight ski course was constructed (length 100m. gradient 12°). The conditions were as follows; wind velocity: 0-0·5ms^?1, temperature: ? 25°C, snow temperature: ?29·5°C.snow density: 0·309 gcm^?3. Running speed was measured by a coil-magnet system. The subject with a small magnet fixed on one leg ran closely down past the coils placed every 5m along the course. Two healthy members of the Japanese Antarctic Research Expedition who were well-trained skiers acted as subjects. Running speed was measured in three different postural conditions (a) standing, (b) egg-shaped, (c) starting in the egg-shaped posture and then standing erect in the latter half of the course. Velocity was measured throughout the course and the following results were obtained: velocities at the final section of the coils, which were placed 65m from the start point, were as follows for each postural condition: Subject KW; (a) standing, 7·6ms^?1 (b) egg-shaped, 8·6ms^?1 (c) egg-shaped followed by standing erect, 8·2ms^?1. Subject B; (a) 7·8ms^?1, (b) 8·9ms^?1, (c) 8·4ms^?1. The friction between the ski and snow was calculated as about 0·13 for all conditions. It was concluded that postural difference may have a considerable and clear-cut effect on running speed even when the skiing speed is rather low.     

Localization of aerosol sources in East-European region by back-trajectory statistics

A concentration-weighted trajectory method for aerosol source localization based on joint statistical analysis of aerosol column volume concentrations and back-trajectory data was used to estimate the spatial distribution of aerosol sources in the East-European region. The aerosol column volume concentration data measured at five AERONET network sites, Belsk, Minsk, Kyiv, Moldova/Kishinev, and Sevastopol, were used. The geographical areas responsible for increased aerosol content at the monitoring sites were mapped separately for coarse-mode and fine-mode aerosol fractions. The investigated area is located between 42° and 62° N in latitude and between 12° and 50° E in longitude.

It was shown that the northeastern territories (in relation to the monitoring stations) give a small contribution to the coarse-mode aerosol content. The events of increased coarse-mode aerosol concentration have been caused by sources in the southeastern regions. On average, the air masses with a large content of coarse-mode aerosol particles were delivered to all stations from regions around Donetsk, Rostov-on-Don, and Kharkiv cities. The fine-mode aerosol fraction originated from areas of Tambov, Voronezh, and Kharkiv cities. The calculated aerosol source regions partly correspond to European Monitoring and Evaluation Programme data for eastern Europe. The cause of difference between calculated regions responsible for increased aerosol content at the monitoring sites and the sources of particle emission according to European Monitoring and Evaluation Programme data are discussed.     

Sleep deprivation,chronic exercise and muscular performance

Muscular performance was tested during 64 hours of sleep deprivation with and without intermittent excercise (treadmill walking at 28% of maximum oxygen intake). The subjects (12 males aged 22·7 ± 2·2 years) carried out a cross-over trial with an 8 week interval separating the two periods of sleep deprivation. The sleep deprivation did not change the time for a 40 m dash, isometric handgrip force or balance (stabilometer test). Vertical jump height decreased, the change being significant for simple sleep deprivation, but not for the combination of deprivation and intermittent exercise. Sleep deprivation decreased isokinetic extension force at 60° s?1, while intermittent walking decreased isokinetic extension force at both 60 and 180° ?1; however, there was no significant difference between exercise plus sleep deprivation and sleep deprivation alone at either angular velocity. We conclude that the moderate intensity of physical activity likely in industrial work has little influence upon human performance under conditions of sleep deprivation.     

Coseismic deformation and source model of the 12 November 2017 MW 7.3 Kermanshah Earthquake (Iran–Iraq border) investigated through DInSAR measurements

A large earthquake with a magnitude of M_W 7.3 struck the border of Iran and Iraq at the province of Kermanshah, Iran. In our study, coseismic deformation and source model of the 12 November 2017 Kermanshah Earthquake are investigated using ALOS-2 ScanSAR and Sentinel-1A/B TOPSAR Differential Interferometric Synthetic Aperture Radar (DInSAR) techniques. Geodetic inversion has been performed to constrain source parameters and invert slip distribution on the fault plane. The optimised source model from joint inversion shows a blind reverse fault with a relatively large right-lateral component, striking 353.5° NNW-SSE and dipping 16.3° NE. The maximum slip is up to 3.8 m at 12–14 km depth and the inferred seismic moment is 1.01 × 10²⁰ Nm, corresponding to M_W 7.3, consistent with seismological solutions. The high-resolution optical images from SuperView-1 satellite suggest that most of the linear surface features mapped by DInSAR measurements are landslides or surface cracks triggered by the earthquake. Coulomb stress changes on the source fault indicating consistency between aftershock distribution and high loaded stress zones. Based on the stress change on neighbouring active faults around this area, the Kermanshah Earthquake has brought two segments of the Zagros Mountain Front Fault (MFF), MFF-1 and MFF-2, 0.5–3.1 MPa and 0.5–1.96 MPa closer to failure, respectively, suggesting the risk of future earthquakes. Recent major aftershocks (M_W≥ 5.0) could probably ease the seismic hazard on MFF-2, but the risk of earthquakes on MFF-2 is still increasing.     

A study of electro‐optical characteristics depending on LC pre‐tilt angle and cell gap in a full‐HD LCOS panel

Abstract— The goal of this work is to achieve a better understanding of the electro‐optical characteristics of a VA‐mode full‐HD LCOS panel via simulations and experiments. The optical parameters, such as reflectance, fill factor, and contrast that vary due to the pre‐tilt angle and cell gap, were also studied. Based on the simulations, the optical fill factor was the highest at an angle of 81° and 2.1 μm under the given conditions. The contrast ratio was the highest at an angle of 89° and 2.4 μm. Five different LCOS panels were fabricated; three different angles (85°, 87°, and 89°) at a 2.1‐μm cell gap and two different cell gaps (1.8 and 2.1 μm) at an angle of 87°. The measured reflected light intensity was compared to the calculated reflectance. The simulated and measured contrasts were compared with each other. The simulation results well‐matched the experimental results and the differences were less than a few percentage points. Based on the comparative studies on reflectance and contrast, the test panel under the condition of an 87° angle and 2.1‐μm gap showed the best performance results.     

基于始终最佳体验的终端聚合的研究与实现*

统一业务终端通过分布式的终端设备协同提供应用体验,是B3G系统终端架构的一个发展方向.统一业务终端形成的终端业务环境提供始终最佳体验的服务模式,并主要体现在其对分布式终端组件的动态聚合重构上.在动态重构聚合的实现中,首先对体验质量进行量化建模,将各分布式终端的能力映射到能力服务器(CS),推导出满意度的评估函数及其约束条件,ABE服务模型.其次,基于此服务模型详细设计出终端聚合控制机制,并且提出解决UST频繁切换所引起的性能瓶颈的快速判决算法.     

Inertial focusing of microparticles in curvilinear microchannels with different curvature angles

Inertial microfluidics has become one of the emerging topics due to potential applications such as particle separation, particle enrichment, rapid detection and diagnosis of circulating tumor cells. To realize its integration to such applications, underlying physics should be well understood. This study focuses on particle dynamics in curvilinear channels with different curvature angles (280°, 230°, and 180°) and different channel heights (90, 75, and 60 µm) where the advantages of hydrodynamic forces were exploited. We presented the cruciality of the three-dimensional particle position with respect to inertial lift forces and Dean drag force by examining the focusing behavior of 20 µm (large), 15 µm (medium) and 10 µm (small) fluorescent polystyrene microparticles for a wide range of flow rates (400–2700 µL/min) and corresponding channel Reynolds numbers. Migration of the particles in lateral direction and their equilibrium positions were investigated in detail. In addition, in the light of our findings, we described two different regions: transition region, where the inner wall becomes the outer wall and vice versa, and the outlet region. The maximum distance between the tight particle stream of 20 and 15 µm particles was obtained in the 90 high channel with curvature angle of 280° at Reynolds number of 144 in the transition region (intersection of the turns), which was the optimum condition/configuration for focusing.     

A fiber-optic temperature sensor

In this paper we demonstrate the feasibility of designing a fiber-optic temperature sensor based on the principles of low-coherent tandem interferometry; the sensitive element represents a plane-parallel plate produced from fused silica of thickness 500 µm (the corresponding measurement range is between 40 and 90°C). In the middle of the range, the temperature resolution reaches 0.03°C RMS and goes down to 0.1°C RMS at the boundaries. The worst-case repeatability of measurements of the sensor makes up 0.2°C.     

Mass and energy flux estimates at different spatial resolutions in a heterogeneous area through a distributed energy–water balance model and remote-sensing data

A physically based, distributed energy–water balance model, Flash-Flood Event-Based Spatially Distributed Rainfall–Runoff Transformation-Energy Water Balance (FEST-EWB) model, and remote-sensing data were analysed to study the representativeness of mass and energy fluxes at different spatial resolutions. The analyses were performed in an agricultural area of Barrax (Spain) in the framework of the Sentinel-2 and Fluorescence Experiment (SEN2FLEX). In particular, there were two main objectives: (1) to evaluate the ability of the distributed hydrological model to compute energy and mass fluxes for a heterogeneous area compared to remote-sensing and ground data and (2) to define the length scales of different processes (evapotranspiration (ET) and land surface temperature (LST)) above which the variance of the different variables becomes insignificant for the process, so that bare soil and vegetation behaviours are no longer distinguishable. Mass and energy fluxes were collected from ground data and from an Airborne Hyperspectral Scanner (AHS), with a spatial resolution between 2 and 4 m, and from the Moderate Resolution Imaging Spectroradiometer (MODIS), with a spatial resolution of 1000 m, and then compared with hydrological model outputs. ET and LST spatial variability was analysed at different spatial resolutions using histograms, statistical parameters, and spatial autocorrelation functions.

Computed ET with the FEST-EWB model at high spatial resolution (10 m) showed for the three days of analysis a mean relative error of 9.4% compared to AHS data, whereas for land surface temperature comparison a relative error of 1.6% was found. Then, LSTs from AHS and FEST-EWB were aggregated at decreasing spatial resolutions (50, 150, 300, 400, 500, 600, 750, and 1000 m), showing that the thermodynamic variability tends to disappear with a lower number of classes in the histograms and with a decrease of the coefficient of variation (CV) and of standard deviation values. At each scale, a similar behaviour was reported between each pair of images, with the values of standard deviation starting, respectively, from 8.9°C and 9.6°C at 10 m of spatial resolution to 7.7°C and 7.9°C at 1000 m of spatial resolution. Similar results were obtained from the spatial aggregation of ET images. The decrease in standard deviation values of LST and ET with a decrease in the scale became substantial around pixel dimensions equal to 400 m.     

Prior knowledge-supported aerosol optical depth retrieval over land surfaces at 500 m spatial resolution with MODIS data

Aerosol optical depth (AOD) values at a spatial resolution of 500 m were retrieved over terrain areas by applying a time series of Moderate resolution Imaging Spectroradiometer (MODIS) 500 m resolution data in the Heihe region (36–42° N, 97–104° E) of Gansu Province, China; in the Pearl River Delta (18–30° N, 108–122° E), China; and in Beijing (39–41° N, 115–118° E), China. A novel prior knowledge scheme was used in the algorithm that performs cloud screening, simultaneous AOD and surface reflectance retrieval from the MODIS 500 m Level 1B data. This prior knowledge scheme produced a new Ångström exponent α, utilizing a Terra pass time α and an Aqua pass time α to better satisfy the invariant α assumption. The retrieved AOD data were compared with AOD data observed with the ground-based, automatic Sun-tracking photometer CE318 at corresponding bands in the Heihe region and with Aerosol Robotic Network (AERONET) data in the Pearl River Delta and in Beijing. Validation experiments demonstrated the potential of applying the algorithm to MODIS 500 m AOD retrieval on land; validation showed the uncertainty of Δτ = ±0.1±0.2τ over various types of underlying land surface, including cities, where τ is the aerosol optical depth. The root mean square errors (RMSEs) were around 0.1 for inland regions and up to 0.24 for cities by the sea, such as Hong Kong and Zhongshan, China.     

SU-8 as resist material for deep X-ray lithography

 A new negative tone resist for deep X-ray lithography is presented. This resist is a nine parts to one mixture of the EPON SU-8 resin with 2,2-bis-(3,5-dichloro-4-hydroxyphenyl)propane (Tetrachlorobisphenol A, TCBA), the latter acting as the photoinitiator. The resist was irradiated at the synchrotron source of DCI at LURE. It was dried for 7 to 20 days beforehand over silica gel while under a light vacuum (20 mbar). Best results for a 150 μm high resist were obtained with a X-ray bottom dose of 3 kJ cm⁻³ and a post exposure bake at 33 °C. Differential Scanning Calorimetry measurements (DSC) determined the glass transition temperature of the resist. The glass transition for the undried, loose resist was 34.7 °C, and it was 28.7 °C when the resist was pressed on a silicon substrate. For a sample of the dried resist, the glass transition was 33.4 °C for the loose resist and 29.8 °C when it was pressed on a Silicon substrate. CD measurements were made on top surface of a set of 100 μm long columns structures, which were produced in 150 μm of this resist. These structures have a constant 100 μm pitch, and the structures themselves varied in width from 20 to 17 μm. For these structures, the CD was calculated to be 0.15 ± 0.03 μm. Received: 8 February 2000/Accepted: 3 March 2000