356 research outputs found
Transboundary Air Pollution: The Legal Framework
12 pages (includes illustrations).
Contains footnotes
Best Regulatory Practices for Deep Seabed Mining: Lessons Learned from the U.S. Surface Mining Control and Reclamation Act
Mining operations around the globe are responsible for significant environmental problems. These problems often stem from poor planning, inadequate regulatory standards, and a failure of regulatory oversight, particularly with respect to inspection and enforcement regimes. Mining regulators are often hamstrung, however, by inadequate information about potential impacts before operations commence. This problem is particularly daunting when considering mining on ocean floors where information about the environment is limited, and the impacts of mining are poorly understood.
As the International Seabed Authority (ISA) develops a comprehensive regulatory program for deep seabed mining, they should draw on the experience gained in regulating terrestrial mining, subject, of course, to the caveat that deep seabed mining poses unique challenges that will require different and sometimes innovative regulatory solutions. In reviewing regulatory programs for terrestrial mining operations, one would be hard-pressed to find a program that is more thorough and creative than that established by the U.S. Surface Mining Control and Reclamation Act (SMCRA). For reasons that are related primarily to the contentious politics surrounding coal mining regulation in the United States, SMCRA has never lived up to its promise. Nonetheless, the law remains largely intact and, despite its implementation challenges, affords a useful framework for thinking about an appropriate strategy for regulating deep seabed mining.
This case study outlines the contours of the regulatory program established under SMCRA insofar as it may be relevant to regulating deep seabed mining. It acknowledges some of SMCRA’s flaws and omissions, and where appropriate, it suggests regulatory practices that go beyond SMCRA. Nonetheless, and despite SMCRA’s limitations, the program established under this law reflects modern thinking about the procedures that should be followed in managing mining activities in challenging environments, and thus offers a useful lens for designing a regulatory program for deep seabed mining
Transboundary Air Pollution: The Legal Framework
12 pages (includes illustrations).
Contains footnotes
Laser Marking of Titanium Coating for Aerospace Applications
Abstract In the aerospace industry, in order to ensure the identification and the traceability of the products, high repeatability, non-invasive and durable marking processes are required. Laser marking is one of the most advanced marking technologies. Compared to traditional marking processes, like punches, microdot, scribing or electric discharge pencil etcher, laser marking offers several advantages, such us: non-contact working, high repeatability, high scanning speed, mark width comparable to the laser spot dimension, high flexibility and high automation of the process itself. In order to assure the mark visibility for the component lifetime, an appropriate depth of the mark is required. In this way, a stable behaviour is ensured also when the component operates in aggressive environments (i.e. in presence of oxidation, corrosion and wear phenomena). The mark depth is strongly affected by the laser source kind and by the process parameters, such us average power, pulse frequency and scanning speed. Moreover, an excessive mark penetration could cause stress concentrations and reduce the fatigue life of the component. Consequently, an appropriate selection of the process parameters is required in order to assure visibility and to avoid excessive damage. Cold Spray Deposition (CSD) is a relative new technology that allows to produce surface coatings without significant substrate temperature increasing. In aeronautics fields this technology is useful to coat materials sensible to temperature, such as solution tempered aluminum alloy, with a titanium layer. Aim of the work is to characterize the laser marking process on CSD Ti coating, in order to study the influence of the laser marking process parameters (pulse power and scanning speed), on the groove geometry of the marking. The experimental marking tests were carried out through a 30 W MOPA Q-Switched Yb:YAG fibre laser; under different process conditions. The groove geometry was measured through a HIROX HK9700 optical microscope. The results showed the effectiveness of the laser process to produce high quality marks on the titanium layer. Moreover, a correlation between the process parameters and the mark's geometry was clearly observed
Acoustic characteristics evaluation of an innovative metamaterial obtained through 3D printing technique
The reduction of interior noise level in the transportation sector is a big problem to cope
with in view to increase the comfort of passengers. For this reason a great emphasis from the
research community is devoted to develop new technology which are able to satisfy the mechanical
requirements with concrete benefits from the acoustic point of view. Currently, it does not exist a
solution for wideband range of frequency. Indeed, porous materials are characterized by
outstanding dissipation in the high frequency range but they exhibit poor performance in the low
and medium frequency range, where instead resonant cavities systems have the best performances
but with narrow-band sound absorption. For this reason, the design and development of new
materials which offers a good acoustic absorption over a wide range of frequencies is requested.
In this paper, a hybrid metamaterial is designed, by coupling resonant cavities with micro-porous
material and obtained through additive manufacturing technique which enables to model complex
geometries that could not be feasible with classical manufacturing. Numerical and experimental
studies have been conducted on the manufactured samples of PLA, with an interesting focus on
the effect of each parameter which affects the absorption properties
Saldatura in configurazione testa a testa di lamiere in lega 2198 T3 mediante procedimento friction stir welding
Scopo del presente lavoro è lo studio della saldabilità mediante processo friction stir welding (FSW) di lamierein lega innovativa alluminio-litio AA 2198 T3 in configurazione di testa. In particolare, mediante tecnichestatistiche, la velocità d’avanzamento e quella di rotazione sono state messe in relazione con le proprietà meccaniche del giunto ed è stato sviluppato un modello empirico di previsione delle suddette caratteristiche alvariare dei parametri di processo. Per lo sviluppo di questo modello, è stato utilizzato un piano fattorialecompleto 32 avente come risposte osservate la resistenza allo snervamento e la resistenza a rottura dei giunti.Il modello sviluppato può essere utilizzato per prevedere le proprietà meccaniche dei giunti con un livello diconfidenza pari al 95%. Inoltre, usando la funzione di desiderabilità (desirability function, DF) sono statitrovati i parametri di processo che massimizzano in maniera bilanciata la resistenza allo snervamento equella alla trazione. Infine, i giunti ottenuti utilizzando i parametri di processo ottimi sono stati sottoposti aprove di fatica e di tensocorrosione al fine di valutarne il potenziale utilizzo nel settore aeronautico. I risultatiottenuti mostrano che i giunti ottenuti tramite questa tecnologia hanno una buona resistenza allatensocorrosione ed un’ottima vita a fatica, paragonabile a quella del materiale base e superiore a quella disaldature ottenute con tecniche tradizionali, come TIG e MIG
Influence of welding parameters and post-weld aging on tensile properties and fracture location of AA2139-T351 friction-stir-welded joints
The Water Transfer Process as a Management Option for Meeting Changing Water Demands, Volume II
1 v. : ill. ; 28 cm
V. 2.: Water transfers in Arizona / Gary C. Woodard, Cara S. McCarthy -- Water transfers in California : 1981-1989 / Brian E. Gray -- Transfers of water use in Colorado / Lawrence J. MacDonnell, Charles W. Howe, Teresa A. Rice -- Transfers of water use in New Mexico / F. Lee Brown, Charles DuMars, Michelle Minnis, Sue Anderson Smasal, David Kennedy, Julie A. Urban -- Review of the water rights transfer process and activity in Utah / Chris C. Hogge, Paul G. Hansen, J. Paul Riley, Ray J. Davis -- Water rights transfers in Wyoming / Mark Squillacehttps://scholar.law.colorado.edu/books_reports_studies/1092/thumbnail.jp
The Water Transfer Process as a Management Option for Meeting Changing Water Demands, Volume I
1 v. : ill. ; 28 cm
V. 1.: Introduction -- Summaries of state reports -- Findings and comparative analysis -- Summary and conclusionshttps://scholar.law.colorado.edu/books_reports_studies/1091/thumbnail.jp
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