A self-heated second stage regulator for underwater divers

This article deals with the development, testing and performance evaluation of a new class of a self-heated breathing regulator for underwater divers.This class of regulators is introduced because of its capability of utilizing the energy of the compressed gas, used in supporting the lives of divers underwater, in heating the inhaled gases as well as in eliminating the problems of regulator freeze-up in cold waters.The paper presents the performance characteristics of the self-heated second stage regulators under different simulated dive temperatures, breathing frequencies and tidal volumes.Comparisons are also presented between the performance of the self-heated regulator and a conventional regulator in order to define the merits and limitations of each type under different dive conditions.The obtained results indicate that the self-heated regulator produced not only warm gases but performed successfully in zero°C waters while the conventional regulator has failed.This paper suggests the potential of the self-heated regulator as viable means for alleviating the problems of cold water diving.     

Optimum design of a servo-controlled breathing regulator for underwater divers

This article deals with the analysis, synthesis and performance evaluation of the flow and dynamic characteristics of the new class of servo-controlled breathing regulators for underwater divers.Emphasis on such a class of regulators has been stimulated by their tremendous potential in extending the dive depth and duration because they reduce the diver breathing effort to a great extent. This would eliminate the unnecessary exhaustion of the diver under such extreme diving conditions and accordingly improve his work efficiency underwater.The study aims at developing rational design procedures and guides that would enable the regulator designers to select the optimal design parameters of this class of regulators. Such design guides are based on the analysis of the flow and dynamic characteristics of the servo-controlled regulator as well as the basic principle of the theory of optimum control.The study presents also experimental evaluation techniques of the dynamic characteristics of this class of regulators in order to provide common quantitative means for comparison with the conventional regulator designs.The presented results emphasize the merits and the potential of the servo-controlled regulators as essential tools of supporting the life of divers underwater.     

Flow characteristics of exhalation valves of diving regulators

This study presents the flow-resistance characteristics of conventional exhalation valves used in underwater diving regulators. Evaluation of such characteristics is essential to quantifying the effect of the main design parameters of these valves on the diver's exhalation effort.Plain, tapered as well as tapered supported valves of different materials have been considered in this study.Valves seats of different geometrical configurations which varied from the simple multi-circular hole seats to the more imaginative Posiden-like seats have been studied. Triangular, multi-quadrant as well as full diaphragm exhalation valves have also been tested in details.New designs of exhalation valves have also been developed and tested in an attempt to define the optimum configuration as well as the best combination of the valve and its seat that would reduce the exhalation effort to a minimum. Among the considered new designs are the vortex and nozzle-assisted exhaust valves.The obtained results show that full diaphragm exhalation valves offer the least breathing resistance followed by the 13-hole Posiden-like exhalation valve, the nozzle-assisted valves and the vortex-assisted valves. Nonetheless, the 2.9-cm diameter plain, unsupported and untapered valve on the six-triangle seat exhibits flow characteristics that are not too far from the most fancy designs.The obtained results presents design guides, for improving the breathing characteristics of the exhalation valves, which can be extremely important to the designers and manufacturers of diving regulators.     

Manned Testing of the Diver Gas Recovery Installation

The Diver Gas Recovery Installation (DGRI) was evaluated at 80 msw saturation - 100 msw excursion diving on HeO2 in the Naval Medical Research Institute (NMRI) of China in April, 1995. The diving depth, lockout time, breathing gas flow rate and consumption, inspired oxygen partial pressure (PO2) and carbon dioxide partial pressure (PCO2) were monitored. The results indicated that PO2 was controlled to fluctuate from 64.3 to 84.0 kPa and PCO2 went up from 0.01 kPa up to O.I kPa during 4 hours excursion diving; recovery of breathing gas reached 95%; three divers felt well and breathed comfortably during simulating heavy work. The test showed that it met desired performance goals. The DGRI is a kind of important equipment for long duration deep dive. It enables the gases exhaled by the divers to be re-cycled, and therefore it has great social, military and economic significance for diving operation and submarine rescue.     

A compressed gas-powered heating system for underwater divers

This article presents a heating system for divers which is totally powered by the compressed gas used in supporting their lives underwater. The pressure energy stored in the breathing gas, which is conventionally wasted through throttling, is utilized to generate a heating effect by expanding the gas in an optimally designed vortex tube.A mathematical model is presented to predict the generated heating effect at different dive depths and ambient temperatures with air and heliox as breathing mixtures.Comparisons are given between the heating effect developed by the system and those required by the divers when wearing different diving suits and working at various work loads. Those comparisons emphasize the potential of the system as a viable means for heating the divers, their inhaled gases as well as their dive gear in a way that eliminates the complexity and hazards of presently available systems.     

Experimental study on the 350 msw simulated heliox saturation-370 msw excursion diving

-The chief purpose of the research was to understand the physiological function change regularity, performance and adaptability of the human body living and working under high pressure for prolonged time.In January 1989, 4 naval divers entered the habital of NMRI's 500 msw saturation diving system after a series of adaptive diving training. The breathing mixture was helium-oxygen. After 55 h compression (including intermediate stages) the 350 msw depth was reached, where the divers lived and worked for 72 h 10 min. No sign of discomfort or significant HPNS was found in the 4 divers.The second and third day of the saturation exposure, the divers carried out 370 msw dry and wet chamber excursion diving 2 man-time each, the divers effectively carried out operational work under water, the total excursion time was 1 h each excursion dive.Saturation decompression started after 3-day storage exposure, the divers were gradually brought toward the surface 25 msw a day on the average by employing the linear stead     

Physico‐chemical features of pupu springs

The physical and chemical features of Pupu Springs (40 51’ S, 172° 46’ E), near Takaka, the largest cold springs in New Zealand and one of the largest in the world, were investigated by scuba diving. The springs have a maximum depth of 6.9 m and a mosaic of substrate types (bedrock, boulders, and gravel). The temperature of the springs water is constant at 11.7°C, water velocities are generally moderate to very strong (25–100 cm.s^‐1), and average water discharge is about 9.6 m³.s^‐1. Mean holding time for water in the springs is 4.4 min. The water is extremely clear, with a vertical extinction coefficient (log10) of 0.09. The springs water flows from an artesian basin in Arthur Marble and is low in dissolved oxygen. The water is rich in calcium (64 g.m^‐3), with a high specific conductivity (65 mS.m^‐1). Information on water temperature, discharge, and chemistry is provided for five other cold springs in New Zealand: Hamurana Springs, Rotorua; Otangaroa Springs, near Putaruru; Three Springs, near Fairlie; Western Springs, Auckland; and a spring at Lake Hayes, Queenstown.     

潜水监控系统的应用研究

通过研究和分析潜水过程中出现的问题,设计了一套针对空气潜水的监控系统.系统利用计算机、视频监控、传感器技术,对潜水员的气源压力、供气压力、潜水深度、潜水时间及潜水过程中拍摄图像声音进行采集和记录.整个系统分为气源压力监测、潜水员深度监测和水下图像声音采集3个模块,可同时对4名潜水员进行实时监控,使水面人员可以准确地掌握...     

The cause of the 2008 cold disaster in the Taiwan Strait

The offshore branch of the China Coastal Current in the Taiwan Strait normally makes a U-turn north of the Zhangyun Ridge. In early 2008, the current continued straight and carried water as cold as 14 °C toward Penghu Island, causing damage to the local aquaculture and coral reef ecosystem. This study investigates the mechanism behind this intrusion of cold water using available data and a three-dimensional model.The model results show that the 2008 intrusion can be divided into three stages. At the beginning of February, the offshore branch of the China Coastal Current formed a U-shape in the Taiwan Strait; the branch moved cold water from the western strait to the central strait when the offshore geostrophic current, which is related to the southward sea level and density gradients, overcame the onshore Ekman transport caused by the northeasterly monsoon. In the second stage, in mid-February, strong northeasterly winds intensified the southwest current in the Taiwan Strait and resulted in abnormal transport of the cold water from the central strait to Penghu Island. Finally, at the end of February, the warm northeast current was re-established due to weakened wind, and the cold water gradually retreated to the north. The second processes occurred immediately after the first, resulting in the unique intrusion of cold water.     

Fòlaga: A low-cost autonomous underwater vehicle combining glider and AUV capabilities

The paper describes the current developments of a class of low-cost, light-weight autonomous underwater vehicles for coastal oceanographic applications; the vehicle class is named Fòlaga, the Italian name of an aquatic bird that swims on the water surface and dives to catch fish. The main design characteristics of the most recent vehicle of the class, the Fòlaga III, are reviewed. Navigation and control system design are discussed, with particular attention to the diving phase, which is accomplished as in oceanographic gliders by varying the vehicle buoyancy and attitude. Experimental results show that the PID robust controllers implemented are effective in the diving control phase. Finally, a distributed cooperation algorithm to be applied by a team of Fòlaga-like vehicles in adaptive oceanographic sampling applications is described. The algorithm optimizes area coverage while taking into account the accuracy in the reconstruction of the oceanographic field and inter-vehicle communication through a range constraint. The resulting dynamic programming algorithm can be implemented in a distributed fashion among the team components.     

Real-Time Adjustment Underwater Positioning System for Submarines

A rapid real-time adjustment scheme is proposed for improving the precision of the conventional short-base line (SBL) positioning fix system used by submarines and other underwater vehicles. In the proposed approach, an initial position estimate is obtained by solving the conventional SBL tracking equations of the submarine given the assumptions of a constant speed of sound in water and a straight-line propagation path. In the first stage of the real-time adjustment procedure, this initial estimate is corrected using an iterative computation scheme based on a 3D geometry model. The improved position estimate is then used to compute a new, more accurate value of the speed of sound in water. Finally, in the second stage of the real-time adjustment procedure, the corrected speed of sound in water and the discrepancy between the original and corrected position estimates obtained in the first adjustment procedure are applied to update the coordinates of the submarine based on the second signal received from the pinger. The numerical results show that the proposed real-time adjustment system yields a significant improvement in the accuracy of the positioning fix estimates compared to those obtained from the conventional SBL method or the SBL method with the first adjustment procedure only.     

2006-2007年长江冲淡水的扩展形态及季节变化

利用2006—2007年观测的高密集度CTD测站和海床基ADCP连续测流站资料,分析了长江冲淡水的扩展形态和垂向结构。结果表明,各季节观测时段内:春季、秋季和冬季的表层长江冲淡水扩展基本被限制在长江口、杭州湾及舟山水域附近。夏季长江冲淡水的扩展由内向外可分为3个阶段:射形流阶段,长江径流直接向东南冲入海;水舌形态扩展阶段,冲淡水以1个水舌的完整形态指向东北,其运动受台湾暖流和南黄海海盆气旋式环流等背景流场的影响明显;扩散阶段,冲淡水先以较大团块运动,后以不断变小的水块随着背景流场运动,其中一支向东北移动进入南黄海,另一支转向东偏南,绕东海东北部冷涡运动。     

寒潮天气下高风险冰块追踪预测方法及数值模拟

为向拟建、在建和已建冰区所有冷源取水工程海域的海冰环境监测和动态风险预警提供技术支撑,本文构建了海冰–海洋耦合条件下的拉格朗日粒子追踪预测模型,并以辽东湾某核电站取水口为例,模拟并探讨了寒潮天气下高风险冰块在24 h、48 h和72 h的运移轨迹及其进入取水口的概率。结果表明,由于取水口的走向与流向和风向几乎垂直,因此在口门外随机释放的1 200个高风险冰块粒子中只有不到6%的粒子进入到取水口内。通过分区域标识粒子颜色,发现这些粒子多来自于靠近取水口300 m范围内。敏感性分析的结果表明,当释放粒子数量增至5倍时,结论不变。该项研究为冷源取水安全预警提供了一种新方法。     

Marine sampling by scuba diving. 3. Sampling procedures for measurement of mercury concentrations in estuarine waters and seawater

A method for sampling estuarine waters and seawater by scuba diving is described. Samples taken from the Krka River Estuary on the eastern Adriatic coast were analysed for mercury content using cold vapour atomic absorption spectrometry (CVAAS). Mercury levels as low as 1 ng dm⁻³ were determined and these are among the lowest values reported to date. A simple contamination free procedure for the preconditioning of sample containers in the sea was applied. Sampling of water by divers is particularly useful when the intermediate layer in an estuary has to be identified and sampled, as well as for obtaining detailed vertical concentration profiles for mercury and other trace elements.     

Target Deployment and Retrieval Using JIAOLONG Manned Submersible in the Depth of 6600 m in Mariana Trench

China''s 7000 m manned submersible JIAOLONG carried out an exploration cruise at the Mariana Trench from June to July 2016. The submersible completed nine manned dives on the north and south area of the Mariana Trench from the depth of 5500 to 6700 m, to investigate the geological, biological and chemical characteristics in the hadal area. During the cruise, JIAOLONG deployed a gas-tight serial sampler to collect the water near the sea bottom regularly. Five days later, the sub located the sampler in another dive and retrieved it successfully from the same location, which is the first time that scientists and engineers finished the high accuracy in-situ deployment and retrieval using a manned submersible with Ultra-Short Base Line (USBL) positioning system at the depth more than 6600 m. In this task, we used not only the USBL system of the manned submersible but also a compound strategy, including five position marks, the sea floor terrain, the depth contour, and the heading of the sub. This paper introduces the compound strategy of the target deployment and retrieval with the practical diving experience of JIAOLONG, and provides a promising technique for other underwater vehicles such as manned submersible or Remote Operated Vehicle (ROV) under similar conditions.     

Fine resolution 3D temperature fields off Kerguelen from instrumented penguins

The use of diving animals as autonomous vectors of oceanographic instruments is rapidly increasing, because this approach yields cost-efficient new information and can be used in previously poorly sampled areas. However, methods for analyzing the collected data are still under development. In particular, difficulties may arise from the heterogeneous data distribution linked to animals’ behavior. Here we show how raw temperature data collected by penguin-borne loggers were transformed to a regular gridded dataset that provided new information on the local circulation off Kerguelen. A total of 16 king penguins (Aptenodytes patagonicus) were equipped with satellite-positioning transmitters and with temperature–time–depth recorders (TTDRs) to record dive depth and sea temperature. The penguins’ foraging trips recorded during five summers ranged from 140 to 600 km from the colony and 11,000 dives >100 m were recorded. Temperature measurements recorded during diving were used to produce detailed 3D temperature fields of the area (0–200 m). The data treatment included dive location, determination of the vertical profile for each dive, averaging and gridding of those profiles onto 0.1°×0.1° cells, and optimal interpolation in both the horizontal and vertical using an objective analysis. Horizontal fields of temperature at the surface and 100 m are presented, as well as a vertical section along the main foraging direction of the penguins. Compared to conventional temperature databases (Levitus World Ocean Atlas and historical stations available in the area), the 3D temperature fields collected from penguins are extremely finely resolved, by one order finer. Although TTDRs were less accurate than conventional instruments, such a high spatial resolution of penguin-derived data provided unprecedented detailed information on the upper level circulation pattern east of Kerguelen, as well as the iron-enrichment mechanism leading to a high primary production over the Kerguelen Plateau.     

Characteristics of water mass under the surface mixed layer in Tsushima Straits and the southwestern Japan Sea in autumn

Two different cold waters were found under the surface mixed layer in Tsushima Straits and the southwestern Japan Sea in autumn 2004. One is cold saline water with a low concentration of dissolved oxygen, and the other is cold less saline water with a high concentration of dissolved oxygen. The older saline water originates from the bottom of the East China Sea, strongly influenced by the Kuroshio water with high salinity. The bottom density in the eastern channel of the Tsushima Straits is coincident with that of the East China Sea in autumn, corresponding to the season when the cold saline water was frequently found in the Tsushima Straits. The newer less saline water originates from the front of Tsushima Warm Current between the Tsushima Warm Current water and the surface cold water in the Japan Sea. This water is formed by subduction above the isopycnal surface from the front of the Tsushima Warm Current.     

Zero-G Class Underwater Robots: Unrestricted Attitude Control Using Control Moment Gyros

The "Zero-G" is designated as a new class of underwater robot that is capable of unrestricted attitude control. A novel control scheme based on internal actuation using control moment gyros (CMGs) is developed to provide Zero-G class autonomous underwater vehicles (AUVs) with this unique freedom in control. This is implemented in the CMG-actuated Zero-G class internal kinematic underwater robot actuation (IKURA) system that was developed as part of this research. A series of experiments are performed to demonstrate the practical application of CMGs and verify the associated theoretical developments. The ability to actively stabilize the translational dynamics of the robot is assessed and unrestricted attitude control is demonstrated in an experiment that involves vertically pitched diving and surfacing in surge. Finally, potential applications for Zero-G class AUVs are discussed.     

Dynamics of surface-air pollution during the passage of a cold front

The dynamics of meteorological parameters, of sodar data on the temperature stratification of the atmospheric boundary layer, and of surface contents of pollutants (nitrogen oxides, carbon monoxide, and ozone) during the passage over Moscow of a structurally complex prominent cold front are discussed. It is shown that the cold front passage is accompanied by stepwise increases in the NO, NO₂, and CO surface contents. A probable cause of this phenomenon is a quick entrainment of smoke plumes from high-altitude sources of pollution into the surface turbulent air near the frontal boundary. Intense advection of cold air at the rear of the cyclone can lead to the development of an unstable stratification in the atmospheric boundary layer even in the nighttime. Under these conditions, the minute-scale variability of contents of trace gases increases abruptly as compared to that occurring in the frontal zone of the cyclone prior to the passage of the front. This effect is statistically significant. The dynamics of surface ozone reflects an increase in its background concentrations in arctic air masses.