An Internet-Based Stated Choices Household Survey for Alternative Fuelled Vehicles

The development of alternative fuelled vehicle technology is a key strategy towards environmental sustainability and improved air quality in cities. Analysis of the role of vehicle technology in fulfilling sustainability targets requires estimates of future vehicle demand. The inability to observe actual car-type preferences for cleaner vehicles has led researchers to the development of stated choice methods. This paper reports on the design and descriptive analysis of a stated choices survey on the demand for alternative fuelled vehicles in the Census Metropolitan Area of Hamilton, conducted through the Internet. Respondents were asked to select the vehicle they would most likely buy out of a set of conventional, hybrid and alternative-fuel options over a time horizon of five years. Characteristics such as vehicle purchase price, fuel and maintenance cost, acceleration, alternative fuel incentives, fuel availability and pollution levels were used to describe each vehicle presented. To our knowledge, this is the first study of its kind that focuses at the urban level and the Canadian context and also, it is the first to demonstrate the time- and cost-efficiency of the Internet in designing and collecting Stated Choices data for automobile demand

On the constitutive modeling of dual-phase steels at finite strains: a generalized plasticity based approach

In this work we propose a general theoretic framework for the derivation of constitutive equations for dual-phase steels, undergoing continuum finite deformation. The proposed framework is based on the generalized plasticity theory and comprises the following three basic characteristics: 1.A multiplicative decomposition of the deformation gradient into elastic and plastic parts. 2.A hyperelastic constitutive equation 3.A general formulation of the theory which prescribes only the number and the nature of the internal variables, while it leaves their evolution laws unspecified. Due to this generality several different loading functions, flow rules and hardening laws can be analyzed within the proposed framework by leaving its basic structure essentially unaltered. As an application, a rather simple material model, which comprises a von-Mises loading function, an associative flow rule and a non-linear kinematic hardening law, is proposed. The ability of the model in simulating simplified representation of the experimentally observed behaviour is tested by two representative numerical examples

On the constitutive modeling of dual-phase steels at finite strains: a generalized plasticity based approach

In this work we propose a general theoretic framework for the derivation of constitutive equations for dual-phase steels, undergoing continuum finite deformation. The proposed framework is based on the generalized plasticity theory and comprises the following three basic characteristics: 1.A multiplicative decomposition of the deformation gradient into elastic and plastic parts. 2.A hyperelastic constitutive equation 3.A general formulation of the theory which prescribes only the number and the nature of the internal variables, while it leaves their evolution laws unspecified. Due to this generality several different loading functions, flow rules and hardening laws can be analyzed within the proposed framework by leaving its basic structure essentially unaltered. As an application, a rather simple material model, which comprises a von-Mises loading function, an associative flow rule and a non-linear kinematic hardening law, is proposed. The ability of the model in simulating simplified representation of the experimentally observed behaviour is tested by two representative numerical examples

An internet-based stated choices household survey for alternative fuelled vehicles

The development of alternative fuelled vehicle technology is a key strategy towards environmental sustainability and improved air quality in cities. Analysis of the role of vehicle technology in fulfilling sustainability targets requires estimates of future vehicle demand. The inability to observe actual car-type preferences for cleaner vehicles has led researchers to the development of stated choice methods. This paper reports on the design and descriptive analysis of a stated choices survey on the demand for alternative fuelled vehicles in the Census Metropolitan Area of Hamilton, conducted through the Internet. Respondents were asked to select the vehicle they would most likely buy out of a set of conventional, hybrid and alternative-fuel options over a time horizon of five years. Characteristics such as vehicle purchase price, fuel and maintenance cost, acceleration, alternative fuel incentives, fuel availability and pollution levels were used to describe each vehicle presented. To our knowledge, this is the first study of its kind that focuses at the urban level and the Canadian context and also, it is the first to demonstrate the time- and cost-efficiency of the Internet in designing and collecting Stated Choices data for automobile demand

The mechanism of propagation of NH3/air and NH3/H2/air laminar premixed flame fronts

The mechanism of flame front propagation in NH3/air and NH3/H2/air steady, laminar premixed flames is examined. Since the process is characterised by a state of chemical non-equilibrium, the analysis focuses on the explosive mode that is introduced by chemical kinetics. The chemistry expressed in this mode is the one that tends to lead the system away from equilibrium and sustains the chemical non-equilibrium state. The algorithmic tools of Computational Singular Perturbation method are employed, so the analysis is not hindered by the size of the detailed chemical kinetics mechanism employed. Under engine-relevant conditions and a stoichiometric mixture, it is shown that in the NH3/air case the flame front propagation is driven by reaction far from the front and by reaction closer to the front; the latter assisted by reaction . These reactions are mainly responsible for the heat released, by effectively feeding the most exothermic reactions, which are OH-consuming. The ensuing chemical activity in the neighbourhood of maximum heat release rate generates upstream diffusion of heat, NH2, NO, H and H2, which initiate the chemical activity ahead of the flame front. This mechanism of front propagation is promoted by H2 addition in the mixture, by reinforcing the action of these three reactions and by activating another OH-producing reaction . A preliminary investigation of lean mixtures indicated that this flame front propagation mechanism is also present in the case of a pure ammonia fuel. However, when H2 is present in the initial mixture, significant changes are observed that relate to the prevailing lower temperatures and the decreased upstream diffusion of heat. These findings provide novel insights with direct implications for controlling and optimising NH3 and NH3/H2 flames planned for engine applications. The approach proposed here can also be extended for analysing flame propagation mechanisms across a more diverse spectrum of fuel mixtures and flame configurations, offering invaluable support to technologies pivotal in the ongoing energy transition efforts

DeSyRe: on-Demand System Reliability

The DeSyRe project builds on-demand adaptive and reliable Systems-on-Chips (SoCs). As fabrication technology scales down, chips are becoming less reliable, thereby incurring increased power and performance costs for fault tolerance. To make matters worse, power density is becoming a significant limiting factor in SoC design, in general. In the face of such changes in the technological landscape, current solutions for fault tolerance are expected to introduce excessive overheads in future systems. Moreover, attempting to design and manufacture a totally defect and fault-free system, would impact heavily, even prohibitively, the design, manufacturing, and testing costs, as well as the system performance and power consumption. In this context, DeSyRe delivers a new generation of systems that are reliable by design at well-balanced power, performance, and design costs. In our attempt to reduce the overheads of fault-tolerance, only a small fraction of the chip is built to be fault-free. This fault-free part is then employed to manage the remaining fault-prone resources of the SoC. The DeSyRe framework is applied to two medical systems with high safety requirements (measured using the IEC 61508 functional safety standard) and tight power and performance constraints

A Stochastic Multi-scale Approach for Numerical Modeling of Complex Materials - Application to Uniaxial Cyclic Response of Concrete

In complex materials, numerous intertwined phenomena underlie the overall response at macroscale. These phenomena can pertain to different engineering fields (mechanical , chemical, electrical), occur at different scales, can appear as uncertain, and are nonlinear. Interacting with complex materials thus calls for developing nonlinear computational approaches where multi-scale techniques that grasp key phenomena at the relevant scale need to be mingled with stochastic methods accounting for uncertainties. In this chapter, we develop such a computational approach for modeling the mechanical response of a representative volume of concrete in uniaxial cyclic loading. A mesoscale is defined such that it represents an equivalent heterogeneous medium: nonlinear local response is modeled in the framework of Thermodynamics with Internal Variables; spatial variability of the local response is represented by correlated random vector fields generated with the Spectral Representation Method. Macroscale response is recovered through standard ho-mogenization procedure from Micromechanics and shows salient features of the uniaxial cyclic response of concrete that are not explicitly modeled at mesoscale.Comment: Computational Methods for Solids and Fluids, 41, Springer International Publishing, pp.123-160, 2016, Computational Methods in Applied Sciences, 978-3-319-27994-

DeSyRe: On-demand system reliability

The DeSyRe project builds on-demand adaptive and reliable Systems-on-Chips (SoCs). As fabrication technology scales down, chips are becoming less reliable, thereby incurring increased power and performance costs for fault tolerance. To make matters worse, power density is becoming a significant limiting factor in SoC design, in general. In the face of such changes in the technological landscape, current solutions for fault tolerance are expected to introduce excessive overheads in future systems. Moreover, attempting to design and manufacture a totally defect-/fault-free system, would impact heavily, even prohibitively, the design, manufacturing, and testing costs, as well as the system performance and power consumption. In this context, DeSyRe delivers a new generation of systems that are reliable by design at well-balanced power, performance, and design costs. In our attempt to reduce the overheads of fault-tolerance, only a small fraction of the chip is built to be fault-free. This fault-free part is then employed to manage the remaining fault-prone resources of the SoC. The DeSyRe framework is applied to two medical systems with high safety requirements (measured using the IEC 61508 functional safety standard) and tight power and performance constraints. (C) 2013 Elsevier B.V. All rights reserved

Unpublished Mediterranean and Black Sea records of marine alien, cryptogenic, and neonative species

To enrich spatio-temporal information on the distribution of alien, cryptogenic, and neonative species in the Mediterranean and the Black Sea, a collective effort by 173 marine scientists was made to provide unpublished records and make them open access to the scientific community. Through this effort, we collected and harmonized a dataset of 12,649 records. It includes 247 taxa, of which 217 are Animalia, 25 Plantae and 5 Chromista, from 23 countries surrounding the Mediterranean and the Black Sea. Chordata was the most abundant taxonomic group, followed by Arthropoda, Mollusca, and Annelida. In terms of species records, Siganus luridus, Siganus rivulatus, Saurida lessepsianus, Pterois miles, Upeneus moluccensis, Charybdis (Archias) longicollis, and Caulerpa cylindracea were the most numerous. The temporal distribution of the records ranges from 1973 to 2022, with 44% of the records in 2020–2021. Lethrinus borbonicus is reported for the first time in the Mediterranean Sea, while Pomatoschistus quagga, Caulerpa cylindracea, Grateloupia turuturu, and Misophria pallida are first records for the Black Sea; Kapraunia schneideri is recorded for the second time in the Mediterranean and for the first time in Israel; Prionospio depauperata and Pseudonereis anomala are reported for the first time from the Sea of Marmara. Many first country records are also included, namely: Amathia verticillata (Montenegro), Ampithoe valida (Italy), Antithamnion amphigeneum (Greece), Clavelina oblonga (Tunisia and Slovenia), Dendostrea cf. folium (Syria), Epinephelus fasciatus (Tunisia), Ganonema farinosum (Montenegro), Macrorhynchia philippina (Tunisia), Marenzelleria neglecta (Romania), Paratapes textilis (Tunisia), and Botrylloides diegensis (Tunisia).peer-reviewe