A Deep-sea Sediment Sampling System—Design, Analysis and Experimental Verification

In order to meet the needs of the deep seabed sediment airtight sampling operation of the whole sea depth manned submersible (operating water depth of 11,000 meters). An airtight sampler with the function of holding pressure and coring was designed. Firstly, Using the sediment sampling test platform, taking high sampling rate as the goal and the motion speed of manipulator as the constraint condition, the sediment sampling rate (ratio of the sample actually retrieved by the sampling tube to the insertion depth of the sampling tube) test under different sampling tube inner diameters was carried out, respectively. Then, the pressure drop calculation and analysis of other components such as pressure retaining cylinder and sealing cylinder during the recovery of airtight sampler to the deck are carried out, and the pressure drop compensation during the recovery of airtight sampler is calculated and analyzed based on the pressure compensator. At last, the internal pressure test, high-pressure cabin test and adaptability test between sampler and manipulator are carried out by using the developed prototype of airtight sampler for sediments in the deep sea. The test results verify the feasibility of the design of airtight sampler for sediments in the deep sea, which will provide strong support for the deep seabed sampling operation of manned submersible in the deep sea.

Measurement of floating oil layer thicknesses at the Santa Barbara seeps in California to support interpretation of satellite imagery

<p>The offshore natural oil seeps along the California coast near Santa Barbara are a natural testing site for the calibration of remote sensing systems aimed at the detection of oil spills. The main difference between these seeps and other permanent sources of floating oil (natural and unnatural seeps in the Gulf of Mexico) is the petroleum composition. Moreover, while it has been documented that most natural seeps worldwide change their rate of oil discharge over time, the Santa Barbara seeps have maintained a high rate, frequently forming thick layers of floating oil in recent years. This allowed us to perform multiple experiments developing floating oil layer thickness measurement techniques from sea-level instruments. These measurements were then used in validation of airborne and satellite remote sensors.</p><p>At the Santa Barbara seeps, we have tested our previously developed method of measuring oil thickness with a crystal tube sampling mechanism that extracts an undisturbed floating oil profile at the sea surface. Samples are then post-processed to quantify the volume of oil captured. Our newer system consists of a submerged spectrophotometer that measures the ultraviolet (UV) and infrared (IR) light attenuation of the floating oil from a fixed UV-IR light source above the water. Both methods have been used for cross validation. The sampling tube is more accurate and precise for thicknesses below 50 um (from silver-rainbow sheens to metallic). Both systems work consistently on thicknesses ranging from >50 um to 350um (the latter was the thickest sample of oil measured at the seep sites). However, the advantage of the submerged spectrophotometer is the real time interpretation of the data. The maximum thickness measured in the laboratory for the submerged spectrophotometer was 2.5mm, while the maximum thickness measured from the sampling tube was 7cm of oil.</p><p>These thickness measuring instruments have been used to validate thermal and multispectral sensors mounted on an Unmanned Aerial System (UAS). By overlaying the thickness measurements collected in the field with synchronous data collected from the UAS sensors we can relate the thermal reflective radiation and multispectral signatures from different oil thicknesses. Maps with oil thickness classifications generated from the UAS data are then used to correlate with quasi-synchronous high resolution satellite images obtained by WorldView2-3, Planet, ALOS-2, and RADARSAT-2, all of which are hosted and viewable on the NOAA-Environmental Response Management Application (ERMA).  Further field expeditions scheduled for 2021 will include the UAVSAR sensor, an L-band airborne synthetic aperture radar operated by the NASA Airborne Science Program. This NASA microwave sensor operates at the same frequency as one of the sensors on the upcoming NASA-ISRO SAR (NISAR) mission scheduled to launch in 2022 and data acquired will be used to both improve thickness algorithm development and simulate the expected performance of the NISAR instrument for oil slick detection and characterization. We will prepare these methods to move to operational use as this new resource comes online adding a significant response asset to oil spill characterization and response.</p>

Simulated and Experimental Study of Sediments Sampling Parameters Based on the VOF Method

Sediments in the seabed hold vital clues to the study of marine geology, microbial communities and history of ocean life, and the remote operated vehicle (ROV) mounted tubular sampling is an important way to obtain sediments. However, sampling in the seabed is a particularly difficult and complicated task due to the difficulty accessing deep water layers. The sampling is affected by the sampler’s structural parameters, operation parameters and the interaction between the sampling tube and sediments, which usually results in low volume and coring rate of sediments obtained. This paper simulated the soft viscous seabed sediments as non-Newtonian Herschel-Bulkley viscoplastic fluids and established a numerical model for the tubular sampling based on the volume of fluid (VOF) method. The influence rules of the sampling tube diameter, drainage area rate, penetration velocity, and sediments dynamic viscosity on coring rate and volume were studied. The results showed that coring volume was negatively correlated with all the parameters except the sampling tube diameter. Furthermore, coring rate decreased with increases in penetration velocity, drainage area rate, and sediments dynamic viscosity. The coring rate first increased and then decreased with increasing of the sampling tube diameter, and the peak value was also influenced by penetration velocity. Then, based on the numerical simulation results, an experimental sampling platform was set up and real-world sampling experiments were conducted. The simulation results tallied with the experimental results, with a maximum absolute error of only 4.6%, which verified that the numerical simulation model accurately reflected real-world sampling. The findings in this paper can provide a theoretical basis for facilitating the optimal design of the geometric structure of the seabed sediments samplers and the parameters in the sampling process.

Inhaled nasopharyngeal nitric oxide concentrations during unilateral nostril breathing – a pilot study

Objective: To assess the influence unilateral nostril breathing has on mean inhaled nasopharyngeal nitric oxide (NO) concentrations compared with unobstructed bilateral nostril breathing in individuals demonstrating a nasal cycle.Methods: After determining the patent and congested nasal sides in healthy adult volunteers (N=10), and sampling air at both nostrils, a small diameter gas sampling tube was passed along the floor of the nose into the volunteer's patent nostril, until it was stationed in the nasopharynx. Nasopharyngeal NO concentrations were then assessed during normal nasal at-rest tidal breathing during three different nasal breathing states: first both nostrils, then allocated in randomised order, patent side only, and congested side only.Results: Nasopharyngeal NO concentrations were consistently higher on both exhalation and inhalation during unilateral congested side nostril breathing, when compared with unilateral patent side nostril breathing, and breathing through both nostrils.Conclusions: During unilateral nostril breathing, inhaled nasopharyngeal NO concentrations are consistently higher on the congested side of the nose.

Numerical Simulation and Experimental Study of a Sediment Sampler Sampling Based on VOF Method

This paper takes the full-ocean-depth sampling device of the mechanical hand-held sampler as the research object, simulates the soft viscous sediment as non-Newtonian Herschel Bulkley viscoplastic fluid, uses the finite volume method and applies the computational fluid mechanics software Fluent to establish the sediment sampling model.VOF method is used to track multiphase flow interface. The effects of the sampling speed, diameter of the sampling tube, drainage discharge and sediment dynamic viscosity on coring rate and sampling volume are studied. The results show that the sampling volume is negatively correlated with those influencing factors. However, the coring rate decreases with the increase of sampling speed, drainage area ratio at inlet and outlet, and dynamic viscosity of sediment. The coring rate first increases and then decreases with the increase of the diameter of the sampling tube, and the peak value is related to the sampling speed and tube diameter. Then, based on the analysis of the numerical simulation results, a sampling simulation experimental platform is built and the sampling experiment is carried out. It can be concluded that the simulation results tally with the experimental results, with the maximum error being only -4.6%, which further verifies the correctness of the numerical model.