Smart materials for subsea buoyancy control

Buoyancy control is needed in small autonomous underwater devices to enable greater flexibility in measurements in the ocean. This project has examined a number of ways in which buoyancy changes might be achieved. Firstly, an extensive review of the mechanisms by which various marine organisms control their buoyancy was undertaken. There is a tremendous diversity of natural buoyancy control mechanisms, but most of these mechanisms produce only slow (and small) changes in buoyancy.Studies were carried out on the behaviour of polymer gel systems that exhibit large volume changes under the influence of solvent composition and/or temperature. The effects of salinity were investigated, from 5 parts per thousand (ppt) to 35ppt, on hydrolysed polyacrylamide gels, over the temperature range of 5°C to 40°C. It was found that the gels decreased in volume in the solutions, this effect being most pronounced in the 35ppt solution. As temperature increased, the volume changes were observed to decrease. The cyclical volumetric strain behaviour of the polyacrylamide gels, by alternate exposure to saline solutions and distilled water, resulted in significant (~200%) volume changes induced over periods of 2 days. In a second study, the density change associated with the volumetric strain of polymeric materials was investigated in poly(N-isopropylacrylamide), NIPA, gels. The temperature-sensitive NIPA gels, immersed in distilled water or seawater solutions at temperatures ranging from 5°C to 50°C, exhibited volume changes of over 800%, and density changes of 30-40%. NIPA gels exhibit a faster response time than polyacrylamide gels, and their density and volume changes have potential application in buoyancy change.Experiments were also performed on NiTi shape memory alloys (SMA), which change in length and mechanical properties with temperature. A controllable parallel-plate device was constructed, linked by four helical SMA springs, which exerted significant axial forces with the application of temperature. The device is capable of producing substantial volume changes if contained in a suitable enclosure. It is currently on loan to the Science Museum, London, as part of a new exhibition of the Wellcome Wing

Creation and deployment of the NEREUS autonomous underwater chemical analyzer and Kemonaut, an odyssey class submarine

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003.Includes bibliographical references (p. 175-181).NEREUS is a compact self-contained low-power submersible membrane-inlet mass spectrometer, designed to measure dissolved volatile gasses in the water column. It is capable of intelligent data collection, analysis and state-based mission control while operating as a stand-alone instrument or onboard the Kemonaut autonomous underwater vehicle (AUV). Kemonaut is an Odyssey class AUV with increased payload carrying capacity and dynamic stability, and is intended for freshwater and coastal marine applications to depths of 300 meters. The NEREUS-Kemonaut system characteristics allow for greatly improved dissolved gas data collection rates, accuracy and mapping resolution over presently available technologies. Applications particularly well suited for the NEREUS-Kemonaut system include identification and mapping of pollution sources such as chemical spills, investigation of enigmatic freshwater and marine ecosystems, assessment of subsurface natural resources and estimation of marine-related greenhouse gas cycling.by Richard Camilli.Ph.D

Underwater Vehicles

For the latest twenty to thirty years, a significant number of AUVs has been created for the solving of wide spectrum of scientific and applied tasks of ocean development and research. For the short time period the AUVs have shown the efficiency at performance of complex search and inspection works and opened a number of new important applications. Initially the information about AUVs had mainly review-advertising character but now more attention is paid to practical achievements, problems and systems technologies. AUVs are losing their prototype status and have become a fully operational, reliable and effective tool and modern multi-purpose AUVs represent the new class of underwater robotic objects with inherent tasks and practical applications, particular features of technology, systems structure and functional properties

Underwater dwellings and sea born structures as paradigms of design

Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1982.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH.Includes bibliographical references.There are many reasons for undertaking a work such as this. Among them are the benefits offered to society when we acknowledge the potential of submersible structures, The provision of habitable underwater space remains an unexploited resource of great potential. Hopefully, it will be utilized in an ethically intelligent manner. Perhaps, the spiritual qualities of water will foster peace engendering or life sustaining pursuits resulting in paradigms of new urban forms and ideals. Herein, a broad view is offered of inspirations and ideologies leading towards a conceptual basis for sea dwellings. Developed from an ontogenesis into criteria for environmental design, siting, energy options and program ethics, a platform for establishing a sea utilization framework is imparted. The structural design development incorporates fundamental considerations for aqueous habitats. Reinforced concrete for sea use is discussed in depth including expositions on hydraulic cements and construction techniques . A basic sea structure design/analysis method which uses thin shell theory to reliably approximate the behavior of thick shells is presented through both simple and complex examples. The volume concludes with a metamorphosis of sea dwelling concepts in the form of original sketches, technical drawings and tone paintings. This thesis attempts to broaden the scope of knowledge of the architectural designer and planner through an effort to bridge ocean sciences, ocean engineering and architectural concerns. With the knowledge thus gained, it may be possible to project further into civilization's potential for cultural development within the limited context of the sea as a dwelling place.by Ricardo Guillermo.M.Arch

Standard Specifications for Highway and Bridge Construction, 2012

When referenced, the 2012 edition of the Iowa Department of Transportation’s (Iowa DOT) Standard Specifications for Highway and Bridge Construction shall be used for contract work awarded by the Iowa DOT. They may also be incorporated by reference in other contract work on secondary, urban, local systems, or other contract work in which the Iowa DOT has an interest. As modified by the General Supplemental Specifications, these Standard Specifications represent the minimum requirements and may be modified by Supplemental Specifications, Developmental Specifications, and Special Provisions on specific contracts. These Standard Specifications have been written so the Contractor’s responsibilities are indicated by plain language using the Imperative Mood and Active Voice form. Sentences are of the form: Construct isolation joints at all points where driveways meet other walks, curbs, or fixtures in the surface. Ensure finished members are true to detailed dimensions and free from twists, bends, open joints, or other defects resulting from faulty fabrication or defective work. Personnel preparing the JMF shall be Iowa DOT certified in bituminous mix design. The Contracting Authority’s responsibilities are (with some exceptions) indicated by the use of the modal verb “will”. Sentences are of the form: The Engineer will obtain and test density samples for each lot according to Materials I.M. 204. Payment will be the contract unit price for Fabric Reinforcement per square yard (square meter). These standard specifications contain dual units of measure: the United States Standard measure (English units) and the International System of Units (SI or “metric” units). The English units are expressed first then followed by the metric units in parentheses. The measurements expressed in the two systems are not necessarily equal. In some cases the measurements in metric units is a “hard” conversion of the English measurement; i.e. the metric unit has been approximated with a rounded, rationalized metric measurement that is easy to work with and remember. The proposal form will identify whether the work was designed and shall be constructed in English or metric units

The Siren of Cirebon: a tenth-century trading vessel lost in the Java Sea

This thesis examines data collected during the salvage of the cargo of a merchant ves-sel foundered in the Java Sea, by a short inscription in a fragment of a bowl and coins dat-ed to around 970 CE. The wreck’s position indicates that the ship was on her way to the island of Java; the verssel herself belongs into the so called ‘lashed-lug and doweled’, Western Austronesian (‘Malayo-Indonesian’) tradition of boat-building. The surviving cargo ranges from Chinese stonewares and Southeast Asian ceramics to Middle Eastern glassware, tin and lead from –proposedly– the Malay Archipelago, and a wide variety of “smaller finds”, most of which can be attributed to the broader area of the western Indian Ocean. The find palpably demonstrates the far-reaching and well-institutionalised trade rela-tions throughout early medieval Asia. It is often assumed that pre-modern Asian com-merce was largely organised in small-scale ventures, the so called “pedlar trade”, and a number of sources indicate structural features of the ships facilitating this commerce that could have supported such a “particularised” exchange. However, a critical assessment of the composition and distribution of the ship’s payload and a virtual reconstruction of the ship and her initial loading pattern reveal that the vessel’s ceramic cargo in all probability was not acquired, handled, and bound to be marketed as a particularised “peddling” ven-ture, but managed by a single authority. The huge amount of ceramics carried on the ves-sel raises questions regarding frequency, volume and modus operandi of maritime ex-changes in tenth-century Southeast Asia, implying that the ship’s tragic voyage was but an attempt at instituting a virtual monopoly in such trade