Multi-functional applications of graphene related materials in cementitious composites

Cementitious composites are the most widely used construction materials with 4.1 billion tonnes of cement being produced globally in 2017. However, cement production is associated with ~7% of the total global anthropogenic CO2 emissions. Moreover, concrete structures suffer from poor durability, with a fifth of the total civil engineering output in the UK being spent on repair and maintenance. The poor durability of concrete structures necessitates frequent inspections and an enhanced structural monitoring regime. Despite the advancements in material science over the years, cementitious composites remain passive structural materials and do not possess any functionalities. The motivation for this research was to take advantage of emerging graphene-related materials (GRMs) to solve the challenges associated with concrete infrastructure and to instigate additional functionalities that would make the material smarter. Initially, the homogenous dispersion of GRMs was experimentally investigated in detail, as this was recognised as a key challenge in the literature. The results showed that a combination of sonication and the use of a polycarboxylate superplasticiser, were effective in homogenously dispersing the main GRM material, graphene nanoplatelets (GNPs), in cementitious systems. Subsequently, the effect of the GRMs on the early age, mechanical and permeability performance of cement pastes and mortars was investigated. It was found that GNPs reduced the fluidity, delayed the hydration, and had a poor microstructural interaction with the cement hydration products. This consequently led to a reduction in the flexural and compressive strengths. An early age beneficial effect with GNPs was found for water, gas, and chloride permeability. The use of GRMs to improve the electrical conductivity performance was also investigated, with the aim to create electrically conductive networks in the composite that could then be used to monitor changes in loading or damage, by triggering a self-sensing response. Natural graphite and GNPs were found to be effective, however, their use in bulk applications would be challenging and instead, their use in coatings was proposed. Finally, an industry survey was carried out to understand the industry perceptions of this novel material and a Lifecycle Assessment (LCA) study was also undertaken to establish the sustainability performance of a novel GNP-cement composite. The results demonstrated the potential of GRMs to improve the permeability performance of cementitious composites and to instigate a functional behaviour.Engineering and Physical Research council (EPSRC) - Grant No. EP/L016095/1-EPSRC Centre for Doctoral Training in Future Infrastructure and Built Environment and Grant No. EP/P02081X/1 - Resilient Materials for Life (RM4L) Costain Group PL

Miejski eksperyment klimatyczny w Atenach - rozkład przestrzenny temperatury

This paper presents the main characteristics and the first results of a large scale experiment undertaken in Athens in the frame of the POLIS research program of the European Commission. Researches have been carried out to investigate the temperature distribution in the major Athens urban area. Twenty stations have been installed since June 1996 and the recorded data have been analyzed. A very important temperature increase has been recorded in the central Athens area. Energy analysis has been shown that temperature increase has a very important impact on the energy consumption of buildings for cooling purposes.Praca przedstawia główne charakterystyki i pierwsze wyniki eksperymentu podjętego na dużą skalę w Atenach w ramach POLIS - programu badawczego Komisji Europejskiej. Badania przeprowadzono w celu poznania rozkładu temperatury powietrza na obszarze Aten. Od czerwca 1996 r. uruchomiono 20 stacji pomiarowych i dokonano analizy uzyskanych danych. Zanotowano wyraźny wzrost temperatury w centrum Aten. Analiza wykazała, że wzrost temperatury wywiera istotny wpływ na ilość energii zużywanej na klimatyzację pomieszczeń

Effect of Natural Graphite Fineness on the Performance and Electrical Conductivity of Cement Paste Mixes for Self-Sensing Structures

Cementitious composites are the most widely used construction materials; however, their poor durability necessitates frequent monitoring and repairs. The emergence of self-sensing composites could reduce the need for costly and time-consuming structural inspections. Natural graphite, due to its low cost and wide availability, is a promising additive to generate an electrically conductive network which could ultimately lead to a self-sensing mechanism. Despite several studies using natural graphite as a conductive additive, the effect of its fineness on the cementitious composite’s performance has not been explored. This study experimentally investigated the effect of three graphite products of varying fineness on the early age, mechanical, and electrical conductivity performance of cement pastes. The fluidity of the graphite-cement paste reduced significantly with increasing graphite fineness, and graphite did not affect the cement hydration. The finer the graphite, the lower the effect on the mechanical performance, as confirmed by compressive strength testing and micro-indentation. Electrical conductivity testing showed that the percolation threshold depended on the graphite fineness and was found at ~20 wt % for the fine and medium graphite, while it increased to 30−40 wt % for the coarse graphite. This is the first study that has investigated holistically the effect of graphite fineness on the performance of cement pastes and will pave the way for using this material as an additive for self-sensing structures

Acute Heart Failure in a Healthy Young Patient after Severe Carbon Monoxide Poisoning

Introduction: Carbon monoxide (CO) poisoning may cause severe cellular hypoxia. Materials and methods: A 28-year-old male presented reduced levels of consciousness and dyspnoea after CO exposure. Clinical examination revealed tachypnoea, bilateral rales, dilated jugular veins and confusion. Troponin I, lactate and carboxyhaemoglobin levels were increased. Thoracic X-ray depicted pulmonary oedema and an echocardiogram, severe heart failure (HF; EF<25%). He was intubated due to clinical deterioration. Results: He remained intubated for 5 days with excellent improvement of left ventricular function (EF>55%). He was discharged 1 week later with full recovery. Discussion: Acute HF is a rare serious complication of CO poisoning, even in healthy young individuals

FUTURE-AI: International consensus guideline for trustworthy and deployable artificial intelligence in healthcare

Despite major advances in artificial intelligence (AI) for medicine and healthcare, the deployment and adoption of AI technologies remain limited in real-world clinical practice. In recent years, concerns have been raised about the technical, clinical, ethical and legal risks associated with medical AI. To increase real world adoption, it is essential that medical AI tools are trusted and accepted by patients, clinicians, health organisations and authorities. This work describes the FUTURE-AI guideline as the first international consensus framework for guiding the development and deployment of trustworthy AI tools in healthcare. The FUTURE-AI consortium was founded in 2021 and currently comprises 118 inter-disciplinary experts from 51 countries representing all continents, including AI scientists, clinicians, ethicists, and social scientists. Over a two-year period, the consortium defined guiding principles and best practices for trustworthy AI through an iterative process comprising an in-depth literature review, a modified Delphi survey, and online consensus meetings. The FUTURE-AI framework was established based on 6 guiding principles for trustworthy AI in healthcare, i.e. Fairness, Universality, Traceability, Usability, Robustness and Explainability. Through consensus, a set of 28 best practices were defined, addressing technical, clinical, legal and socio-ethical dimensions. The recommendations cover the entire lifecycle of medical AI, from design, development and validation to regulation, deployment, and monitoring. FUTURE-AI is a risk-informed, assumption-free guideline which provides a structured approach for constructing medical AI tools that will be trusted, deployed and adopted in real-world practice. Researchers are encouraged to take the recommendations into account in proof-of-concept stages to facilitate future translation towards clinical practice of medical AI

Cabbage and fermented vegetables : From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19

Large differences in COVID-19 death rates exist between countries and between regions of the same country. Some very low death rate countries such as Eastern Asia, Central Europe, or the Balkans have a common feature of eating large quantities of fermented foods. Although biases exist when examining ecological studies, fermented vegetables or cabbage have been associated with low death rates in European countries. SARS-CoV-2 binds to its receptor, the angiotensin-converting enzyme 2 (ACE2). As a result of SARS-CoV-2 binding, ACE2 downregulation enhances the angiotensin II receptor type 1 (AT(1)R) axis associated with oxidative stress. This leads to insulin resistance as well as lung and endothelial damage, two severe outcomes of COVID-19. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the most potent antioxidant in humans and can block in particular the AT(1)R axis. Cabbage contains precursors of sulforaphane, the most active natural activator of Nrf2. Fermented vegetables contain many lactobacilli, which are also potent Nrf2 activators. Three examples are: kimchi in Korea, westernized foods, and the slum paradox. It is proposed that fermented cabbage is a proof-of-concept of dietary manipulations that may enhance Nrf2-associated antioxidant effects, helpful in mitigating COVID-19 severity.Peer reviewe

Nrf2-interacting nutrients and COVID-19 : time for research to develop adaptation strategies

There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPAR gamma:Peroxisome proliferator-activated receptor, NF kappa B: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2 alpha:Elongation initiation factor 2 alpha). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT(1)R axis (AT(1)R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity