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.

Sequential Sampling and Estimation of Approximately Bandlimited Graph Signals

Graph signal sampling has been widely studied in recent years, but the accurate signal models required by most of the existing sampling methods are usually unavailable prior to any observations made in a practical environment. In this paper, a sequential sampling and estimation algorithm is proposed for approximately bandlimited graph signals, in the absence of prior knowledge concerning signal properties. We approach the problem from a Bayesian perspective in which we formulate the signal prior by a multivariate Gaussian distribution with unknown hyperparameters. To overcome the interconnected problems associated with the parameter estimation, in the proposed algorithm, hyperparameter estimation and sample selection are performed in an alternating way. At each step, the unknown hyperparameters are updated by an expectation maximization procedure based on historical observations, and then the next node in the sampling operation is chosen by uncertainty sampling with the latest hyperparameters. We prove that under some specific conditions, signal estimation in the proposed algorithm is consistent. Subsequent validation of the approach through simulations shows that the proposed procedure yields performances which are significantly better than existing state-of-the-art approaches notwithstanding the additional attribute of robustness in the presence of a broad range of signal attributes.

Design and Experimental Study of Pressure Compensation System for Full-Ocean-Depth Gas-Tight Sediment Sampler

Aiming at the requirement of the full-ocean-depth (operating water depth 11000 meters) manned submersible to carry out the gas-tight sampling operation of the abyss seabed sediment, a kind of full-ocean-depth carrier submersible mechanical hand-held, full-ocean-depth gas-tight sediment sampler (GTSS) with the function of pressure-retaining and coring is designed. Firstly, the volume change model of pressure compensator is established, and it is pointed out that the volume of pressure compensator is about 16.14% equal to the volume of gas-tight sediment sampler (GTSS). Secondly, the pressure compensator is analyzed and calculated, and the relationship between the precharge pressure of the pressure compensator, the nominal volume of the pressure compensator and the pressure holding effect of the gas-tight sediment sampler (GTSS) is studied. The results show that with the increase of gas precharge pressure in the pressure compensator, the final pressure of the sampler also increases. Under the same precharge pressure condition, the larger the nominal volume of the pressure compensator, the greater the final pressure of the sampler. Finally, the air tightness test method is designed by using the developed gas tightness sampler of the full-ocean-depth product, and the change of the final pressure in the gas tight sampler under different precharge pressure is observed. The test results are consistent with the simulation results, indicating the correctness of the pressure compensation system (PCS) model.

Guia do oceanógrafo: Manuseio de cabos e acessórios

Oceanography is a multidisciplinary science that deals with the physical, chemical, geological e biological aspects of the marine environment. As most of the sciences, oceanographic research relies heavily on sampling procedures, which can be rather simple, as obtaining a water sample at sea surface, or very complex, as bringing an uncontaminated sediment sample from hadal regions (up to 11,000 m deep) to the surface. Despite the sampling operation complexity, it is of primary importance the use of the adequate instrumentation, as well the expertise of the instrument operator. Ideally, the operator should have a good knowledge of the technical characteristics of the instruments themselves, as well as the correct procedures for their operation. In addition, he should be well acquainted to the ship equipment employed in the deployment, operation and retrieval of those instruments, including cables, winches and cranes. Only if these aspects are taken in account a reliable and safe operation can be attained. In this way, this guide was conceived as a basic reference for researchers in their on-board operations, although certainly being useful for a wide range of outdoor activities. It was based on the authors years of experience in field work onboard research and fishing vessels. It includes notions on nautical cables, onboard load handling equipment and hardware, basic ropework, basic net weaving and repairing and a nautical glossary.

Evaluation of Fish Farm Effluent Contamination Using Bio-Indicators Based on Macroinvertebrate Communities

The progress of the aquaculture industry in Iran as an environmental and economical maintainable process needs an efficient and low-cost tool for regular checking of adjacent environments. Biological monitoring by macroinvertebrate is operative for assessment of water quality. Sampling operation was carried out to investigate the influence of aquaculture wastewater on macroinvertebrate communities at 4 stations over one year (spring, summer, autum and winter) in the Chehel Chai River. 2040 (19% spring, 18% summer, 25% autumn and 38% winter) macroinvertebrate specimens belonging to 6 orders and 14 families were recognized. The most abundance among the stations belonged to the Diptera and Chironomidae. Two groups of macroinvertebrate assemblages (sensitive to tolerance) and three groups of stations (upstream, outfall and down1 and down2) were identified with Heat map analysis. The study was showed that rainbow trout farm most often significantly increase in the influence of fine particulate organic material (FPOM %), NO3 and PO4. According to HFBI results, organic water pollution at different stations was classified as good (upstream), appropriate, relatively poor and poor (outfall). The combined results of the biomarkers were showed that the outfall station had more organic contamination than its predecessor station (relatively poor water quality) which required more efficient management based on the self-purification capacity of the Chehel Chai River.

Development of the Third Generation of the Dual-Reciprocating Drill

The dual-reciprocating drill (DRD) is a low-mass alternative to traditional drilling techniques biologically inspired by the wood wasp ovipositor, which is used to drill into wood in order to lay its eggs. The DRD reciprocates two halves lined with backwards-facing teeth, enabling it to generate traction forces that reduce the required overhead penetration force. While previous research has focused on experimental testing of the drill’s operational and design parameters, numerical simulation techniques are being developed to allow the rapid testing of multiple designs, complementing and informing experimental testing campaigns. The latest DRD design iteration integrated a novel internal actuation mechanism and demonstrated the benefits of adding controlled lateral movements. This paper presents an exploration of how bit morphology affects drilling performance and a preliminary study of discrete element method (DEM) simulations for modelling DRD interactions in regolith. These have shown how regolith grain size and microscopic behaviour significantly affects the performance of different drill designs, and demonstrated how customisable drills can exploit the properties of various substrates. Two system prototypes are also being developed for the DRD’s third generation, each utilising novel actuation and sampling mechanisms. A final drill design will then be deployed from a planetary rover and perform the first DRD drilling and sampling operation.

Quadratic Interpolation Based on Robot Trajectory Denoising for Human Motion Imitation

Telerobotic has been introduced into complex environment to imitate human dexterous motion, such as remote surgeries on medical sites. However, presence of noise often leads to non-smooth target trajectory, causing robot to vibrate severely. Although most high-end robotic arms have facilitated torque control with torque sensors, it is costly and hard to realize widely in different scenarios. For the purpose of inexpensive and easy realized method, this paper proposes a model free based approach, which is divided as follows: The first part is “signal denoising” by applying empirical mode decomposition to target signals and smoothing out some of components with Savitzky-Golay filter. The second part is “quadratic interpolation” by applying down sampling operation on target signals to minimize robot vibration, adding more sample points to fit original signals, and then interpolating with quadratic polynomial functions. Through this scheme of signal processing, we generate simpler target signals that resemble original signals with piecewise constant acceleration values. The results are also provided to demonstrate the improvement of several input parameter values during experiments. In this paper, an approach is presented to match telerobotic target signals for human motion imitation to robotic arms kinematic motion.

Chemical assessment of the explosive chamber in the projector system of Hayabusa2 for asteroid sampling

We report a chemical assessment of the explosive chamber in the projector system used during the sampling operation of the Hayabusa2 project at the surface of the C-type asteroid Ryugu. Although the explosion process was designed as a closed system (cf. Sawada et al., Space Sci. Rev., 2017), volatile combustion gases and semivolatile organics were produced together with quenched carbonaceous product. The chemical compositions of the gases, organics, and inorganics were investigated in the screening analysis. A solid-phase microextraction technique and thermal desorption coupled with gas chromatography/mass spectrometry analysis revealed that aliphatic (<C20 n-alkanes) and aromatic (<pyrene) hydrocarbons were produced in the closed chamber system. The aromatic ring compositions of the latter showed a semilogarithmic decrease: one ring > two rings > three rings > four rings, resulting in abiogenic molecular patterns. The most intense inorganic fingerprints were due to potassium (K+) and chloride (Cl–) ions derived from the initial KTB explosive and RK ignition charge. We discuss quality control and quality assurance issues applicable to future sample processes during the Hayabusa2 project.

Assessment of the explosive chamber in the projector system of Hayabusa2 for asteroid sampling

We report an assessment of the explosive chamber in the projector system used during the sampling operation of the Hayabusa2 project at the surface of the C-type asteroid Ryugu. Although the explosion process was designed as a closed system (cf. Sawada et al., Space Sci. Rev., 2017), volatile combustion gases and semivolatile organics were produced together with quenched carbonaceous products. The chemical compositions of the gases, organics, and inorganics were investigated in the screening analysis. A solid-phase microextraction technique and thermal desorption coupled with gas chromatography/mass spectrometry analysis revealed that aliphatic ( three rings > four rings, resulting in abiogenic molecular patterns. The most intense inorganic fingerprints were due to potassium (K + ) and chloride (Cl – ) ions derived from the initial KTB explosive and RK ignition charge. We discuss quality control and quality assurance issues applicable to future sample processes during the Hayabusa2 project.