A trend analysis approach for air quality network data

Trend analysis of air pollutant concentrations becomes problematic when applied to data from air quality monitoring networks containing time series of differing lengths. The average trend from such data can be misleading due to biases in the monitoring network. For example, if new monitoring sites located in more polluted locations are added to a network, the introduction of these time series can leverage the trend upwards. A method for resolving this problem was developed, using rolling window regression to recursively calculate the change in pollutant concentration as a function of time, which can be used as a proxy for the true trend. The efficacy of the method was established by conducting simulations with known trends. The rolling change trend was shown to more accurately reflect the true trend than simply averaging the time series. Application of the technique to estimate trends in NO x , NO 2 and NO 2 /NO x concentrations at London roadside monitoring sites over the period 2000–2017 revealed clear differences from the simple average. In particular, a significant monotonic downward trend in NO x concentration was observed, in stark contrast to the average trend, which suggested little change in NO x concentration had occurred over the same period. By accurately representing trends using time series of different lengths, this method has the benefit of being able to describe changes in air quality for locations and time periods with otherwise insufficient data

An empirical study of the variability in the composition of British freight trains

As part of the broader sustainability and economic efficiency agenda, European transport policy places considerable emphasis on improving rail’s competitiveness to increase its share of the freight market. Much attention is devoted to infrastructure characteristics which determine the number of freight trains which can operate and influence the operating characteristics of these trains. However, little attention has been devoted to the composition of the freight trains themselves, with scant published data relating to the practicalities of this important component of system utilisation and its impacts on rail freight viability and sustainability. This paper develops a better understanding of the extent to which freight train composition varies, through a large-scale empirical study of the composition of British freight trains. The investigation is based on a survey of almost 3,000 individual freight trains, with analysis at four levels of disaggregation, from the commodity groupings used in official statistics down to individual services. This provides considerable insight into rail freight operations with particular relevance to the efficiency of utilisation of trains using the available network paths. The results demonstrate the limitations of generalising about freight train formations since, within certain commodity groupings, considerable variability was identified even at fairly high levels of disaggregation

Testing the nexus between C&D waste management strategies & GHG emission performances : the case of UK student accommodation refurbishment projects

All governments, industry sectors and societies each have a pivotal role to play if we are to mitigate anthropogenic climate change. For the construction industry, limiting emissions and addressing issues of sustainability is not just important for reducing the environmental impacts of the sector, but is simply good practice. This research investigates the nexus between the generation and management of waste and greenhouse gas performance in the refurbishment sector, with specific focus on UK student accommodation projects. Performance data from three case study projects were analysed in order to: evaluate the types and extent of wastes and how they are managed; the greenhouse gas impacts of each project waste management strategy; and an assessment is undertaken to estimate the number of BREEAM waste credits that each project would have achieved. The research concludes that the overall greenhouse gas performance of a project’s waste management strategy is highly dependent on how specific high emission impact factor waste streams are managed, and notably, there is a disconnect between waste targets, legislation and sustainability benchmarking schemes that measure success based on the levels of diverting waste from landfill, and the emission performance of waste management strategies. A key area of risk potentially overlooked relates to the scenarios where proportionally small quantities of high emission wastes (e.g. plastics) were sent to landfill alongside large quantities of low emission wastes (e.g. aggregates, bricks, etc.). To ensure the increased emission performance of the refurbishment sector, greater focus is needed on preventing specific categories of waste from the landfill pathway

Global Boundary Stratotype Section and Point (GSSP) for the Anthropocene Series: Where and how to look for potential candidates

International audienc

Nonlocal postbuckling analysis of graphene sheets with initial imperfection based on first order shear deformation theory

In this paper, the first order shear deformation theory (FSDT) is used to investigate the postbuckling behavior of orthotropic single-layered graphene sheet (SLGS) under in-plane loadings. Nonlocal elasticity theory and von-Karman nonlinear model in combination with the isogeometric analysis (IGA) have been applied to study the postbuckling characteristics of SLGSs. In contrast to the classical model, the nonlocal continuum model developed in this work considers the size-effects on the postbuckling characteristics of SLGSs. FSDT takes into account effects of shear deformations through-the-thickness of plate. Geometric imperfection which is defined as a very small transverse displacement of the mid-plane is applied on undeformed nanoplate to create initial deviation in graphene sheet from being perfectly flat. Nonlinear governing equations of motion for SLGS are derived from the principle of virtual work and a variational formulation. At the end, the results are presented as the postbuckling equilibrium paths of SLGS. The influence of various parameters such as edge length, nonlocal parameter, compression ratio, boundary conditions and aspect ratio on the postbuckling path is investigated. The results of this work show the high accuracy of nonlocal FSDT-based analysis for postbuckling behavior of graphene sheets. Keywords: Postbuckling analysis, Graphene sheet, Nonlocal elasticity, First order shear deformation theory, Isogeometric analysis, Initial imperfectio

Metformin beyond an anti-diabetic agent: A comprehensive and mechanistic review on its effects against natural and chemical toxins

In addition to the anti-diabetic effect of metformin, a growing number of studies have shown that metformin has some exciting properties, such as anti-oxidative capabilities, anticancer, genomic stability, anti-inflammation, and anti-fibrosis, which have potent, that can treat other disorders other than diabetes mellitus. We aimed to describe and review the protective and antidotal efficacy of metformin against biologicals, chemicals, natural, medications, pesticides, and radiation-induced toxicities. A comprehensive search has been performed from Scopus, Web of Science, PubMed, and Google Scholar databases from inception to March 8, 2023. All in vitro, in vivo, and clinical studies were considered. Many studies suggest that metformin affects diseases other than diabetes. It is a radioprotective and chemoprotective drug that also affects viral and bacterial diseases. It can be used against inflammation-related and apoptosis-related abnormalities and against toxins to lower their effects. Besides lowering blood sugar, metformin can attenuate the effects of toxins on body weight, inflammation, apoptosis, necrosis, caspase-3 activation, cell viability and survival rate, reactive oxygen species (ROS), NF-κB, TNF-α, many interleukins, lipid profile, and many enzymes activity such as catalase and superoxide dismutase. It also can reduce the histopathological damages induced by many toxins on the kidneys, liver, and colon. However, clinical trials and human studies are needed before using metformin as a therapeutic agent against other diseases