Underwater Acoustics and Cavitating Flow of Water Entry

The fluid mechanics of water entry is studied through investigating the underwater acoustics and the supercavitation. Underwater acoustic signals in water entry are extensively measured at about 30 different positions by using a PVDF needle hydrophone. From the measurements we obtain (1) the primary shock wave caused by the impact of the blunt body on free surface; (2) the vapor pressure inside the cavity; (3) the secondary shock wave caused by pulling away of the cavity from free surface; and so on. The supercavitation induced by the blunt body is observed by using a digital high-speed video camera as well as the single shot photography. The periodic and 3 dimensional motion of the supercavitation is revealed. The experiment is carried out at room temperature.

Viscosity, Surface Tension, and Atomization of Water-Methanol and Diesel Emulsions

This article is the result of experimental studies of the rheologv, viscosities, surface tensions, and atomization of water-methanol and diesel emulsions. The Span 80 and Tween 60 are employed to make three emulsifying agents, Y01, Y02, and Y03, with viscosity of 1.32-1.5 Pa s and HLB values of 5.36, 4.83, and 4.51, respectively. In the water-in-oil emulsions, the aqueous phase is between 10% and 50%; the agent concentration added is 0.8-8.0%. The viscosity of the emulsions is 0.003-0.02 Pa s, and the surface tens ion is 0.04-0.1 N/m. The types and concentrations of agents significantly influence the viscosity of the emulsions, and the higher concentration of the aqueous phase (<50%) in creases the viscosities of the emulsions, especially for higher agent concentration. Interfacial membrane and HLB values of the agents can explain all these phenomena. Higher aqueous phase concentration and agent viscosity results in larger Sauter mean diameter.

The interaction between poly(vinylpyrrolidone) and reversed micelles of water/AOT/n-heptane

The interactions between poly(vinylpyrrolidone) (PVP) and the reversed micelles composed of water, AOT, and n-heptane are investigated with the aid of phase diagram, measurements of conductivity and viscosity, Fourier transform infrared (FTIR) spectrum, and dynamic light scattering (DLS). The phase diagrams of water/AOT/heptane in the presence of and absence of PVP are given. The conductivity of the water/AOT/heptane reversed micelle without PVP initially increases and then decreases with the increase of water content, ω0 (the molar ratio of water to AOT), while the plots of conductivity (K) versus ω0 of the reversed micelle in the presence of PVP depend on the PVP concentrations. The plot of K versus ω0 with 2.0%wt PVP is similar to that without PVP. Only the ω0,max (the water content that the maximum conductivity corresponds to) is larger than that without PVP. Nevertheless, the conductivity of the reversed micelle containing more than 4%wt PVP always rises with the increase of the water content in the measured range. The DLS results indicate that the hydrodynamic radius (Rh) in the presence and absence of PVP rises with the increase of ω0. The plots with PVP and without PVP have almost the same value when ω0<17; and after that, it quickly increases with the increase of ω0. It is interesting to find that there is almost no effect of the PVP concentration on the viscosity and Rh of the reversed micelle at ω0 = 15. The FTIR results suggest that the contents of SO3--bound water and Na+-bound water both decrease with PVP added, while the content of the bulky-like water increases. However, the trapped water in the hydrophobic chain of the surfactant is nearly unaffected by PVP. It is also found from the FTIR that the carbonyl group stretching vibration of AOT is fitted into two sub-peaks, which center at 1740 and 1729 cm-1, corresponding to the trans and cis conformations of AOT, respectively.

On the interaction of water waves and seabed by the porous medium model

The interaction of water waves and seabed is studied by using Yamamoto's model, which takes into account the deformation of soil skeletal frame, compressibility of pore fluid flow as well as the Coulumb friction. When analyzing the propagation of three kinds of stress waves in seabed, a simplified dispersion relation and a specific damping formula are derived. The problem of seabed stability is further treated analytically based on the Mohr-Coulomb theory. The theory is finally applied to the coastal problems in the Lian-Yun Harbour and compared with observations and measurements in soil-wave tank with satisfactory results.

Carmel Lagoon Water Quality and Steelhead Soundings: Fall 2007

ESSP 660 Advanced Watershed Science and Policy is a graduate class taught in the Master of Science in Coastal and Watershed Science & Policy program at California State University Monterey Bay. In 2007, the class was taught in four 4-week modules, each focusing on making a small contribution to a local watershed issue. This report describes the results of one of those 4-week modules – on Carmel Lagoon Water Quality and Ecology. The module was lead instructed by Fred Watson (CSUMB) and Kevan Urquhart (MPWMD). (Document contains 54 pages)

Carmel River Lagoon Enhancement Project: Water Quality and Aquatic Wildlife Monitoring, 2006-7

This is a report to the California Department of Parks and Recreation. It describes water quality and aquatic invertebrate monitoring after the construction of the Carmel River Lagoon Enhancement Project. Included are data that have been collected for two years and preliminary assessment of the enhanced ecosystem. This report marks the completion of 3-years of monitoring water quality and aquatic habitat. The report adopts the same format and certain background text from previous years’ reporting by the same research group (e.g. Larson et al., 2005). (Document contains 100 pages)

Carmel River Lagoon Enhancement Project: Water Quality and Aquatic Wildlife Monitoring, 2005-6

In summer and fall 2004, the California Department of Parks and Recreation (DPR) initiated the Carmel River Lagoon Enhancement Project. The project involved excavation of a dry remnant Arm of the lagoon and adjacent disused farmland to form a significant new lagoon volume. The intention was to provide habitat, in particular, for two Federally threatened species: the California Red-Legged Frog, and the Steelhead Trout (South Central-Coastal California Evolutionary Significant Unit). DPR contracted with the Foundation of California State University Monterey Bay (Central Coast Watershed Studies Team, Watershed Institute) to monitor water quality and aquatic invertebrates in association with the enhancement, and to attempt to monitor steelhead using novel video techniques. The monitoring objective was to assess whether the enhancement was successful in providing habitat with good water quality, adequate invertebrate food for steelhead, and ultimately the presence of steelhead. (Document contains 102 pages)

Tidal oscillations at the head of Monterey Submarine Canyon and their relation to oceanographic sampling and the circulation of water in Monterey Bay. Annual report, Part 6, September 1972

During a 25-hour hydrographic times series at two stations near the head of Monterey Submarine Canyon, an internal tide was observed with an amplitude of 80 to 115 m in water depths of 120 and 220 m respectively. These large oscillations produced daily variations in hydrographic and chemical parameters that were of the same magnitude as seasonal variations in Monterey Bay. Computed velocities associated with the internal tide were on the order of 10 em/sec, and this tidally induced circulation may have a significant role in the exchange of deep water between Monterey Submarine Canyon and the open ocean. (PDF contains 49 pages)

Issues and options related to management of Silver Springs rhesus macaques

Management options for the Silver Springs free-ranging rhesus macaque population range from removal to active maintenance of the population in situ. Selection of a management option is dependent upon which issues are perceived to be true problems. Management options are presented along with their effectiveness in dealing with issues previously described.(31 page document)

Charting multidisciplinary research and action priorities towards the conservation and sustainable management of sea turtles in the Pacific Ocean: a focus on Malaysia

The four sea turtle species found in Malaysia are the leatherback, olive ridley, green and hawksbill. The threats to these species are acute. Populations of leatherback, olive ridley and hawksbill turtles are on the brink of collapse – threatening a biodiversity crisis in Malaysia and the region. This proceedings contains 8 technical papers presented at a workshop convened in Kijal, Terengganu to chart new directions in the conservation of Malaysia's critically endangered sea turtles and to reverse population decline. They represent a wide range of issues from aspects of biology to a review of 40 years of sea turtle conservation. A paper on the socioeconomic linkages and impacts of fisheries was also included as the workshop adopted a multidisciplinary approach to address the issues. Two case studies, including successful restoration examples from international experiences and restoration efforts in Sabah, pave the way for enhancing turtle conservation in the country.

Reconnaissance of the geology and ground-water resources of Columbia County, Florida

The Floridan aquifer was found to be principal source of ground water in the area, containing artesian water in the northern part of Columbia County, and being recharged in the southern part of the county. A few wells in the northern part of the county tap water present in sediments that lie above the Floridan aquifer. These shallow waters are generally high in iron and tannic acid. The details on the geology and hydrology necessary to conserve and utilize the water available to the residents of Columbia County are presented in this study. (PDF contains 86 pages)

Panel Discussion - Management of Eurasian watermilfoil in the United States using native insects: State regulatory and management issues

While researchers have evaluated the potential of native insect herbivores to manage nonindigenous aquatic plant species such as Eurasian watermilfoil ( Myriophyllum spicatum L.), the practical matters of regulatory compliance and implementation have been neglected. A panel of aquatic nuisance species program managers from three state natural resource management agencies (Minnesota, Vermont and Washington) discussed their regulatory and policy concerns. In addition, one ecological consultant attempting to market one of the native insects to manage Eurasian watermilfoil added his perspective on the special challenges of distributing a native biological control agent for management of Eurasian watermilfoil.