Linear viscoelastic properties of high reclaimed asphalt content mixes with biobinders

The use of high Reclaimed Asphalt (RA) content mixtures together with binders produced from renewable resources (biobinders) is one of the current challenges in pavement engineering research. On one hand, RA has been used for decades but there are still some concerns about its performance, especially when high contents are used (>30%). On the other hand, biobinders are relatively new materials which have to be deeply characterised and studied in order to develop good-practices for their use. In this paper, linear viscoelastic properties of biobinders and bio-mixtures manufactured with high-RA content and biobinders are analysed and discussed. High-modulus mixtures with 50% RA were selected for the mix design. Binders and mixtures were tested over a wide range of asphalt service temperatures and frequencies by means of DSR and two-point bending tests respectively. Results show that biobinders have an important effect on mixtures behaviour. However, no direct links between their linear viscoelastic properties were found. Bio-asphalt mixtures still need further development for commercial exploitation; however the take-away fact of this investigation is that it is possible to manufacture asphalt-like mixtures with acceptable viscoelastic properties while being composed only of RA and non-petroleum based binders

Ion Sieving Effects in Chemically Tuned Pillared Graphene Materials for Electrochemical Capacitors

Supercapacitors offer high power densities but require further improvements in energy densities for widespread commercial applications. In addition to the conventional strategy of using large surface area materials to enhance energy storage, recently, matching electrolyte ion sizes to material pore sizes has been shown to be particularly effective. However, synthesis and characterization of materials with precise pore sizes remain challenging. Herein, we propose to evaluate the layered structures in graphene derivatives as being analogous to pores and study the possibility of ion sieving. A class of pillared graphene based materials with suitable interlayer separation were synthesized, readily characterized by X-ray diffraction, and tested in various electrolytes. Electrochemical results show that the interlayer galleries could indeed sieve electrolyte ions based on size constrictions: ions with naked sizes that are smaller than the interlayer separation access the galleries, whereas the larger ions are restricted. These first observations of ion sieving in pillared graphene-based materials enable efficient charge storage through optimization of the d-spacing/ion size couple

Optimal inference with suboptimal models:Addiction and active Bayesian inference

When casting behaviour as active (Bayesian) inference, optimal inference is defined with respect to an agent's beliefs - based on its generative model of the world. This contrasts with normative accounts of choice behaviour, in which optimal actions are considered in relation to the true structure of the environment - as opposed to the agent's beliefs about worldly states (or the task). This distinction shifts an understanding of suboptimal or pathological behaviour away from aberrant inference as such, to understanding the prior beliefs of a subject that cause them to behave less 'optimally' than our prior beliefs suggest they should behave. Put simply, suboptimal or pathological behaviour does not speak against understanding behaviour in terms of (Bayes optimal) inference, but rather calls for a more refined understanding of the subject's generative model upon which their (optimal) Bayesian inference is based. Here, we discuss this fundamental distinction and its implications for understanding optimality, bounded rationality and pathological (choice) behaviour. We illustrate our argument using addictive choice behaviour in a recently described 'limited offer' task. Our simulations of pathological choices and addictive behaviour also generate some clear hypotheses, which we hope to pursue in ongoing empirical work

Guidelines for the implementation of SMARTI: Sustainable Multifunctional Automated Resilient Transport Infrastructure

The World's transport infrastructures (TI) network is facing fast changes due to population growth, mobility, business trades and globalization. More challenges are coming from unforeseen natural and human-induced hazards, including climate change's effects. Meanwhile, technology development continues apace, and new solutions from multi-disciplinary sectors could help solve the main challenges faced by the TI industry. This work presents “SMARTI”, a vision that aims at engineering and implementing concepts such as Sustainability, Multifunctionality, Automation and Resilience within the design, construction and management of TI. As a result, the paper provides roadmaps for each of the above-mentioned pillars, identifying aims, current practices and stepping stones that infrastructure managers, policymakers and governors should consider toward more sustainable TI within 2030

Cracking in asphalt materials

This chapter provides a comprehensive review of both laboratory characterization and modelling of bulk material fracture in asphalt mixtures. For the purpose of organization, this chapter is divided into a section on laboratory tests and a section on models. The laboratory characterization section is further subdivided on the basis of predominant loading conditions (monotonic vs. cyclic). The section on constitutive models is subdivided into two sections, the first one containing fracture mechanics based models for crack initiation and propagation that do not include material degradation due to cyclic loading conditions. The second section discusses phenomenological models that have been developed for crack growth through the use of dissipated energy and damage accumulation concepts. These latter models have the capability to simulate degradation of material capacity upon exceeding a threshold number of loading cycles.Peer ReviewedPostprint (author's final draft

Recognition of Depression in Older Medical Inpatients

BACKGROUND: Studies of recognition of depression in older (aged 65 or more) medical inpatients show low rates of recognition of depression by attending physicians. However, few studies have compared different measures of recognition of depression. OBJECTIVES: (1) To compare the validity of four indicators of recognition of depression and a global measure of recognition against a diagnosis of depression and (2) to explore the effect of patient characteristics on recognition of depression. METHODS: In a cohort of 264 medical inpatients 65 years and older (115 with major or minor depression, 78 with no depression), sensitivities, specificities, and diagnostic odds ratios (DOR) of 4 indicators of recognition (symptoms, diagnosis, treatment, and referral) and a global measure of recognition (any of the 4 indicators) were calculated. The associations between patient characteristics (age, sex, history of depression, antidepressant use before admission, severity of depression, comorbidity, duration of hospitalization, disability, and hospital of admission) and recognition were explored using multiple logistic regression. RESULTS: Less than half of the depressed patients were recognized. The indicator with the highest sensitivity was treatment (27.8%, 95% confidence interval [CI] 20.0–37.0), whereas the indicator with the best specificity was diagnosis (96.6%, 95% CI 91.9–98.7). The unadjusted DOR of global recognition was 2.6 (95% CI 1.5, 4.4). Less comorbidity, more severe depression symptoms, a history of depression, longer hospital stay, and antidepressant use before admission were significantly associated with better global recognition. CONCLUSION: Recognition of depression in elderly medical inpatients depends upon the indicator of recognition used

A molecular roadmap of the AGM region reveals BMP ER as a novel regulator of HSC maturation

In the developing embryo, hematopoietic stem cells (HSCs) emerge from the aorta-gonad-mesonephros (AGM) region, but the molecular regulation of this process is poorly understood. Recently, the progression from E9.5 to E10.5 and polarity along the dorso-ventral axis have been identified as clear demarcations of the supportive HSC niche. To identify novel secreted regulators of HSC maturation, we performed RNA sequencing over these spatiotemporal transitions in the AGM region and supportive OP9 cell line. Screening several proteins through an ex vivo reaggregate culture system, we identify BMP ER as a novel positive regulator of HSC development. We demonstrate that BMP ER is associated with BMP signaling inhibition, but is transcriptionally induced by BMP4, suggesting that BMP ER contributes to the precise control of BMP activity within the AGM region, enabling the maturation of HSCs within a BMP-negative environment. These findings and the availability of our transcriptional data through an accessible interface should provide insight into the maintenance and potential derivation of HSCs in culture.Peer reviewe