Prediction of ductile fracture in anisotropic steels for pipeline applications

Large diameter steel pipelines for gas transportation may experience extreme overloads due to external actions such as soil sliding, faults movements, third part interactions. In these scenarios the material undergoes severe plastic strains which locally may reach the fracture limits. Due to the manufacturing process, the steels used in such applications have an anisotropic behavior both for plasticity and fracture. In this paper two steel grades have been characterized in view of anisotropic plastic fracture. Fracture tests have been planned to characterize the fracture behavior under different stress states and in different directions to define the anisotropic sensitivity. Finite element modelling, incorporating an anisotropic plasticity formulation, has been used to calculate the local fracture parameters in the specimens and to define the complete ductile fracture locus. An uncoupled damage evolution law has been finally used to evaluate the fracture limits on real pipelines failed in full scale laboratory tests. The strain to fracture prediction has been verified by local strain measurements on the fractured pipes. The model robustness has been also verified on global parameter predictions, such us the burst pressur

An analysis of preferences of sixth grade elementary pupils in the field of language.

Thesis (Ed.M.)--Boston Universit

We are More Than our Executive Functions: on the Emotional and Situational Aspects of Criminal Responsibility and Punishment

In Responsible Brains (MIT Press, 2018), Hirstein, Sifferd and Fagan apply the language of cognitive neuroscience to dominant understandings of criminal responsibility in criminal law theory. The Authors make a compelling case that, under such dominant understandings, criminal responsibility eventually ‘translates’ into a minimal working set of executive functions (MWS) that are primarily mediated by the frontal lobes of the brain. In so arguing, the Authors seem to unquestioningly accept the law’s view of the “responsible person” as a mixture of cognitive capacities and mechanisms—thereby leaving aside other fundamental aspects of individuals’ human agency. This commentary article offers a critique of the Authors’ rationalist and individualist approach. The critique can be summarized through the following claim: We humans, as responsible beings, are more than our executive functions. This claim articulates through four main points of discussion: (1) role of emotions in moral judgments and behavior; (2) executive functions and normative criteria for legal insanity; (3) impact of adverse situational factors on executive functions; (4) Authors’ account of punishment and, especially, rehabilitation

Sustainability assessment of wheat production using Emergy

Sustainability of crop production has to be given high priority when global biomass resources are limited. Here emergy evaluation is applied in order to assess sustainability of crop production exemplified by winter wheat. Emergy evaluation takes into account all inputs involved in a production system (i.e. renewable and non-renewable, local and imported) and transforms them into a common measure of direct and indirect solar energy requirement. The evaluation of winter wheat production is conducted by comparing conventional and organic management on two soil types using Danish reference conditions. The resource use efficiency of wheat production per kg biomass is higher using conventional management practices. This is due to high yield based on large use of non-renewable resources. The environmental loading ratio from organic management practices is about a third of the conventional implying that the organic management can be considered more sustainable

State-of-the-art all-silicon sub-bandgap photodetectors at telecom and datacom wavelengths

Silicon-based technologies provide an ideal platform for the monolithic integration of photonics and microelectronics. In this context, a variety of passive and active silicon photonic devices have been developed to operate at telecom and datacom wavelengths, at which silicon has minimal optical absorption - due to its bandgap of 1.12 eV. Although in principle this transparency window limits the use of silicon for optical detection at wavelengths above 1.1 μm, in recent years tremendous advances have been made in the field of all-silicon sub-bandgap photodetectors at telecom and datacom wavelengths. By taking advantage of emerging materials and novel structures, these devices are becoming competitive with the more well-established technologies, and are opening new and intriguing perspectives. In this paper, a review of the state-of-the-art is presented. Devices based on defect-mediated absorption, two-photon absorption and the internal photoemission effect are reported, their working principles are elucidated and their performance discussed and compared

Estimating and visualizing perceived accessibility to transportation and urban facilities

In this paper we present some estimated functions of residential location utility, perceived by individuals, varying with the distance from selected transportation and urban facilities, such as metro and train stations, highway and road junctions, as well as hospitals, green spaces and leisure centres. By summing up such functions we get a measure of the overall convenience of residing in different zones of a given study area, that we call “perceived accessibility”. The functions, estimated by means of SP-surveys, have been implemented into an accessibility Interactive Visualisation Tool (i.e. InViTo) and applied to case study of Rome (Italy). The application allows to validating the use of interactive visualization tools to measure accessibility and its potential usability to produce easy-to-read accessibility maps of urban scenarios of urban development

Chemical Looping for Combustion of Solid Biomass: A Review

Chemical looping combustion of solid biomass has the unique potential to generate energy with negative carbon emissions, while entailing an energy penalty compared to traditional combustion that is lower than that of the competing carbon capture technologies. In spite of these attractive features, research is still needed to bring the technology to a fully commercial level. The reason relies on a number of technological challenges mostly related to the oxygen carrier performance, its possible detrimental interaction with the biomass ash components, and the efficiency of the gas-solid contact with the biomass volatiles. This review is focused on these specific challenges which are particularly relevant when firing biomass rather than coal in a solid-based chemical looping combustion process. Special attention will be given to the most recent findings published on these aspects. Related performance evaluation by modeling, system integration, and techno-economic analysis will also be briefly reviewed

Future mobility and land use scenarios: Impact assessment with an urban case study

In recent years the interest in urban mobility has grown considerably, not only due to the local increase in negative externalities generated by transport, but also because recent technological innovations are offering effective solutions especially in urban context. In particular, the introduction of Connected and Automated Vehicles (CAVs) could radically change the mobility scenario allowing, on the one hand, a widespread diffusion of shared vehicles that could feed the stations of the mass rapid transit network, improving the attractiveness of Public Transportation (PT), and on the other, the implementation of Travel Demand Management (TDM) measures on large areas of the most densely urbanized (and congested) territory of a city, without reducing accessibility and creating social exclusion. The present study aims at evaluating, through a system of Land-Use Transportation Interaction (LUTI) models, the impacts on transport demand and on population and activities location, of transportation policies oriented to both enhancing PT and restricting the individual use of the car. The case study analyzed is represented by the urban area of Rome. Several scenarios have been simulated and compared by means of sustainability indicators. Preliminary results show that the improvement of PT services, combined with the introduction of car use restriction and car free areas, do induce not only a significant modal shift towards more sustainable transportation modes, but also a limitation of urban sprawl

Non-thermal photons and direct photodissociation of H2, HD and HeH+ in the chemistry of the primordial Universe

Non-thermal photons deriving from radiative transitions among the internal ladder of atoms and molecules are an important source of photons in addition to thermal and stellar sources in many astrophysical environments. In the present work the calculation of reaction rates for the direct photodissociation of some molecules relevant in early Universe chemistry is presented; in particular, the calculations include non-thermal photons deriving from the recombination of primordial hydrogen and helium atoms for the cases of H2, HD and HeH+. New effects on the fractional abundances of chemical species are investigated and the fits for the HeH+ photodissociation rates by thermal photons are provided.Comment: 6 pages, 4 figures, 1 table; accepted for publication on MNRA