Onboard offshore platforms the wear imposed on pipes used for the transport of gases can be severe. The transport pipes potentially contain highly flammable and explosive hydrocarbon gases and hence the dangers that can be created by a leaking joint are serious. In these offshore installations, to minimise the danger created by a hydrocarbon gas leak, companies and government agencies proposing to commission oil or gas platforms often complete a safety study. This study includesd etailso f safetyp roceduresa nd the potentiale ffectsc reatedb y leaks. At present the methods used are based on the assumption that the leaks are all from more well known circular cross-sectional jets. This project was initiated to study leaking flange joints which are a typical source for gas leaks. Many leak geometries and a range of pipeline pressures up to a maximum of 410kPa were studied to consider their effect on the resulting gas leak jet. Laser light sheet imaging was used to obtain flow visualisation images, with total pressure probe measurements providing valuable time-averaged data. This alloweda two-dimensionasl liceo f the emergingle akj et to be studiedi n detail with two very differenta nalyticatl echniques. A steady core was observed at the point of exit of each gas jet studied. The core was shown to be a region in which the shear layers, initiated at the jet boundaries, grow towards a merging point on the jet centreline. At this location, the velocity decay rate was found to increase as the jet entered into a second flow regionWithin this region, the rate of velocity decay was shown to be similar to that typically observed in a planar jet. This is much slower than would develop in a roundj et. At the downstreamli mit of the experimentaml easurementsa, t hird flow region was observed. The centreline velocity within this region showed no tendencyt o a lineard ecayr ate as would be foundi n a round cross-sectionje t. Significant differences were noted between the spreading angle of a round jet and those included in the present study. A wide range of spreading angles were observed, which suggests that it is unrealistic for all flange joint leaks to be represented by the round jet assumption. More specifically, because of the effect of spreading angle, the round jet assumption is likely to show discrepancies in predicting the magnitude of important parameters, such as the gas concentration levelsa nde ntrainmenrta tes. As safetys tudiesa re at presentb asedo n circularc ross-sectiojne t data, the findings of this report indicate that the validity of those safety studies is probably being compromised

Commodity computer systems today do not provide system support for privacy. As a result, given the creation of new leak opportunities by ever-increasing software complexity, leaks of private data are inevitable. This thesis presents Suliban and Lacuna, two systems that allow programs to execute privately on commodity hardware. These systems demonstrate different points in a design space wherein stronger privacy guarantees can be traded for greater system usability. Suliban uses trusted computing technology to run computation-only code privately; we refer to this protection as "cloaking". In particular, Suliban can run malicious computations in a way that is resistant to analysis. Suliban uses the Trusted Platform Module and processor late launch to create an execution environment entirely disjoint from normal system software. Suliban uses a remote attestation protocol to demonstrate to a malware distribution platform that the environment has been correctly created before the environment is allowed to receive a malicious payload. Suliban's execution outside of standard system software allows it to resist attackers with privileged operating system access and those that can perform some forms of physical attack. However, Suliban cannot access system services, and requires extra case-by-case measures to get outside information like the date or host file contents. Nonetheless, we demonstrate that Suliban can run computations that would be useful in real malware. In building Suliban, we uncover which defenses are most effective against it and highlight current problems with the use of the Trusted Platform Module. Lacuna instead aims at achieving forensic deniability, which guarantees that an attacker that gains full control of a system after a computation has finished cannot learn answers to even binary questions (with a few exceptions) about the computation. This relaxation of Suliban's guarantees allows Lacuna to run full-featured programs concurrently with non-private programs on a system. Lacuna's key primitive is the ephemeral channel, which allows programs to use peripherals while maintaining forensic deniability. This thesis extends the original Lacuna work by investigating how Linux kernel statistics leak private session information and how to mitigate these leaks. / text

This thesis deals with the development of a mathematical model for an air brake system in the presence of leaks. Brake systems in trucks are crucial for ensuring the safety of vehicles and passengers on the roadways. Most trucks in the US are equipped with S-cam drum brake systems and they are sensitive to maintenance. Brake defects such as leaks are a major cause of accidents involving trucks. Leaks in the air brake systems affect braking performance drastically by decreasing the peak braking pressures attained and also increasing the time required to attain the same, thereby resulting in longer stopping distances. Hence there is a need for detecting leaks in an air brake system. In this thesis, a mathematical model for an air brake system in the presence of leaks is developed with a view towards developing an automatic leak detection system in the near future. The model developed here builds on an earlier research at Texas A&M University in which a "fault free" model of an air brake system is developed, i.e., a mathematical model of an air brake system that predicts how the pressure in the brake chamber evolves as a function of the brake pedal input when there are no leaks in the air brake system.In order to develop a model for an air brake system in the presence of leaks, one must characterize a "leak". A leak may be characterized by the location and its size. Since the pipes are short, the location of the leak does not significantly affect the evolution in the brake pressure as much as its size. For this reason, "effective area" of the leak was chosen as a characteristic of the leak. It was estimated by fitting an empirical relation for leak with leak flow measurement data. The supply pressure and effective area of leak comprised the inputs to the model along with the displacement of the foot pedal (treadle valve plunger). The model was corroborated with the experimental data collected using the setup at Texas A&M University.

Made available in DSpace on 2014-10-09T12:49:23Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:38Z (GMT). No. of bitstreams: 1 09879.pdf: 4439389 bytes, checksum: 92b1531270de0e5ca436e1a7ccef70f9 (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo

Made available in DSpace on 2014-10-09T12:45:23Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:38Z (GMT). No. of bitstreams: 1 07305.pdf: 6236592 bytes, checksum: 1f920b4143a55ab60268becf1f4af7fb (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo

Made available in DSpace on 2014-10-09T12:38:19Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:38Z (GMT). No. of bitstreams: 1 05681.pdf: 6544120 bytes, checksum: 39fb67d11e03881826cd6fa65d2fdde5 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:49:23Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:38Z (GMT). No. of bitstreams: 1 09879.pdf: 4439389 bytes, checksum: 92b1531270de0e5ca436e1a7ccef70f9 (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo

Made available in DSpace on 2014-10-09T12:45:23Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:38Z (GMT). No. of bitstreams: 1 07305.pdf: 6236592 bytes, checksum: 1f920b4143a55ab60268becf1f4af7fb (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo

Made available in DSpace on 2014-10-09T12:38:19Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:38Z (GMT). No. of bitstreams: 1 05681.pdf: 6544120 bytes, checksum: 39fb67d11e03881826cd6fa65d2fdde5 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

The goal of this thesis is to design architecture capable of processing big data with focus on data leaks. For this purpose multiple data storage systems were described a and compared. The proposed architecture can load, process, store and access data for analytic purposes while taking into account authentication and authorisation of users and principles of modern agile infrastructure.