Torque converter turbine noise and cavitation noise over varying speed ratio

These investigations will discuss the operational noise caused by automotive torque converters during speed ratio operation. Two specific cases of torque converter noise will be studied; cavitation, and a monotonic turbine induced noise. Cavitation occurs at or near stall, or zero turbine speed. The bubbles produced due to the extreme torques at low speed ratio operation, upon collapse, may cause a broadband noise that is unwanted by those who are occupying the vehicle as other portions of the vehicle drive train improve acoustically. Turbine induced noise, which occurs at high engine torque at around 0.5 speed ratio, is a narrow-band phenomenon that is audible to vehicle occupants currently. The solution to the turbine induced noise is known, however this study is to gain a better understanding of the mechanics behind this occurrence. The automated torque converter dynamometer test cell was utilized in these experiments to determine the effect of torque converter design parameters on the offset of cavitation and to employ the use a microwave telemetry system to directly measure pressures and structural motion on the turbine. Nearfield acoustics were used as a detection method for all phenomena while using a standardized speed ratio sweep test. Changes in filtered sound pressure levels enabled the ability to detect cavitation desinence. This, in turn, was utilized to determine the effects of various torque converter design parameters, including diameter, torus dimensions, and pump and stator blade designs on cavitation. The on turbine pressures and motion measured with the microwave telemetry were used to understand better the effects of a notched trailing edge turbine blade on the turbine induced noise.

BALTHMETRIC SURVEY IN THE KEWEENAW WATER WAY IN MICHIGAN, USA, MAKING 3D MODEL, AND COMPARING SONAR EQUIPMENT OF THE MODERN AUV AND THE TRADITIONAL SINGLE BEAM SONAR

This thesis represents the overview of hydrographic surveying and different types of modern and traditional surveying equipment, and data acquisition using the traditional single beam sonar system and a modern fully autonomous underwater vehicle, IVER3. During the thesis, the data sets were collected using the vehicles of the Great Lake Research Center at Michigan Technological University. This thesis also presents how to process and edit the bathymetric data on SonarWiz5. Moreover, the three dimensional models were created after importing the data sets in the same coordinate system. In these interpolated surfaces, the details and excavations can be easily seen on the surface models. In this study, the profiles are plotted on the surface models to compare the sensors and details on the seabed. It is shown that single beam sonar might miss some details, such as pipeline and quick elevation changes on the seabed when we compare to the side scan sonar of IVER3 because the single side scan sonar can acquire better resolution. However, sometimes using single beam sonar can save your project time and money because the single beam sonar is cheaper than side scan sonars and the processing might be easier than the side scan data.

Reverse Engineering the Structural and Acoustic Behavior of a Stradivari Violin

There is a tremendous amount of mystery that surrounds the instruments of Antonio Stradivari. There have been many studies done in the past, but no one completely understands exactly how he made his instruments, or why they are still considered the best in the world. This project is designed to develop an engineering model of one of Stradivari's violins that will accurately simulate the structural and acoustic behavior of the instrument. It also hopes to shine some light on what makes the instruments of Stradivari unique when compared to other violins. It will focus on geometry and material properties, utilizing several modern engineering tools, including CT scanning, experimental modal analysis, finite element analysis, correlation techniques, and acoustic synthesis.

Mycobacterium ulcerans persistence at a village water source of Buruli ulcer patients

Buruli ulcer (BU), a neglected tropical disease of the skin and subcutaneous tissue, is caused by Mycobacterium ulcerans and is the third most common mycobacterial disease after tuberculosis and leprosy. While there is a strong association of the occurrence of the disease with stagnant or slow flowing water bodies, the exact mode of transmission of BU is not clear. M. ulcerans has emerged from the environmental fish pathogen M. marinum by acquisition of a virulence plasmid encoding the enzymes required for the production of the cytotoxic macrolide toxin mycolactone, which is a key factor in the pathogenesis of BU. Comparative genomic studies have further shown extensive pseudogene formation and downsizing of the M. ulcerans genome, indicative for an adaptation to a more stable ecological niche. This has raised the question whether this pathogen is still present in water-associated environmental reservoirs. Here we show persistence of M. ulcerans specific DNA sequences over a period of more than two years at a water contact location of BU patients in an endemic village of Cameroon. At defined positions in a shallow water hole used by the villagers for washing and bathing, detritus remained consistently positive for M. ulcerans DNA. The observed mean real-time PCR Ct difference of 1.45 between the insertion sequences IS2606 and IS2404 indicated that lineage 3 M. ulcerans, which cause human disease, persisted in this environment after successful treatment of all local patients. Underwater decaying organic matter may therefore represent a reservoir of M. ulcerans for direct infection of skin lesions or vector-associated transmission.

Acoustic Detection of Organic Enrichment in Sediments at a Salmon Farm Is Confirmed by Independent Groundtruthing Methods

Acoustic backscatter contrast in depositional sediments under salmon farm cages in the Bay of Fundy, Canada, was correlated with localized changes in (unknown) sediment geotechnical properties, as indicated by 4 independent measures of organic enrichment. Sediment total sulfides and redox potentials, enzyme hydrolyzable amino acids, sediment profile imaging and macrofaunal samples, taken at mid-cage positions, each rejected the null hypothesis that salmon cage footprints, defined acoustically as high backscatter areas, were indistinguishable from nearby reference areas. Acoustic backscatter imaging appears capable of mapping organic enrichment in depositional sediments caused by excessive inputs of salmon farm wastes associated with intensive aquaculture.

Pile-dwellings of the Neolithic and the Bronze Age in Switzerland. Long-term research and future tasks

Swiss lake-side settlements dating between 4300 and 800 BC were first recognized in the early 19th century and between 1854 and 1880 early research boomed due to the first scientific studies and the artificial lowering of lakes in Western Switzerland. In the 20th century underwater and wetland archaeology experienced an enormous surge not only because of large rescue excavations, due to extensive motorway construction projects but also due to the evolution of modern IT technology in the 1970s. For the first time huge quantities of ancient wooden structures could be dated by dendrochronology. This produced a quantum leap in the 150 years of pile-dwelling research. In 2011, the UNESCO World Heritage Committee recognized the outstanding universal value of these sites. This article presents an overview about Swiss pile-dwellings of the Neolithic and the Bronze Age and the results of two recent diploma works (case study Sutz-Lattrigen Haupstation innen and case study Seedorf Lobsigensee) as examples of research and cooperation between universities and government agencies for cultural heritage management.

Bathymetry of Lake Constance – a High-Resolution Survey in a Large, Deep Lake

Within the project “Tiefenschärfe – hochauflösende Vermes- sung Bodensee” a high-resolution seamless terrain model is created using airborne topobathymetric laserscanning and multibeam echosounder (MBES) techniques. The project visu- alizes the enormous wealth of features of underwater land- scapes of lakes. The combination of hydroacoustic (multibeam echosounder) and laser-optic (topobathymetric laserscan- ning) methods was used for the first time in a freshwater body of this size. Opportunities, limitations and restrictions of these high-resolution methods are presented.

NEENAWA: Network in Eastern European Neolithic and Wetland Archaeology: first steps.

Neolithic and Bronze Age wetland sites around the Alps (so called pile-dwellings, Pfahlbauten or palafittes in German/French) are of outstanding universal value (UNESCO-world heritage since 2011). Typical sites are in lakes, rivers and bogs, dating between 5300 and 800 BC. Of common character is the perfect conservation of wood, textiles from plant fabrics and many other organic materials. Larger quantities of sub-fossilized wood, as in the peri-alpine sites, offer the possibility of high-precision dating by dendrochronology. Research in these wetland sites started in the mid-19th century. Through large scale rescue excavations since the 1970s and the evolution of underwater archaeology in the same period the Swiss accumulated a thorough experience with these specific sites. Research in wetland sites is shared between cantonal institutions and universities and led to a worldwide unique accumulation of knowledge. Comparable sites exist outside of the Alpine area, but in much smaller quantities. Regions like Russia (small lakes in NW-Russia) and Macedonia (medium size lakes in the border zone of Macedonia, Albania and Greece) have a high scientific potential; rivers in Ukraine are supposed to have the same type of sites.

Anthropogenic Impacts on the Corner Rise Seamounts, North-West Atlantic Ocean

Here we report the first direct underwater observations of extensive human-caused impacts on two remote seamounts in the Corner Rise complex (north-western Atlantic). This note documents evidence of anthropogenic damage on the summits of Kukenthal peak (on Corner Seamount) and Yakutat Scamount, likely resulting from a limited Russian fishery from the mid- 1970s to the mid-1990s, highlighting how bottom trawling can have long-term detrimental effects oil deep-water benthic fauna.

The Nurturing of Seagliders By the National Oceanographic Partnership Program

The National Oceanographic Partnership Program provided critical support to the development of Seaglider long-range autonomous underwater vehicles. This support enabled: (1) development and integration of chemical and biological sensors, (2) transition to low-power, bi-directional satellite communication, and (3) software upgrades to enhance capability and reliability. Sponsored improvements led to setting the mission endurance and range records for autonomous underwater vehicles, wide use by the oceanographic community and licensing for commercialization.