• 1 H, 13 C, 15 N backbone resonance assignment for the 1–164 construct of human XRCC4

      Cabello-Lobato, Maria Jose; Schmidt, Christine K.; orcid: 0000-0002-8363-7933; email: christine.schmidt@manchester.ac.uk; Cliff, Matthew J.; orcid: 0000-0002-7482-0234; email: matthew.cliff@manchester.ac.uk (Springer Netherlands, 2021-06-25)
      Abstract: DNA double-strand breaks (DSBs) represent the most cytotoxic DNA lesions, as—if mis- or unrepaired—they can cause cell death or lead to genome instability, which in turn can cause cancer. DSBs are repaired by two major pathways termed homologous recombination and non-homologous end-joining (NHEJ). NHEJ is responsible for repairing the vast majority of DSBs arising in human cells. Defects in NHEJ factors are also associated with microcephaly, primordial dwarfism and immune deficiencies. One of the key proteins important for mediating NHEJ is XRCC4. XRCC4 is a dimer, with the dimer interface mediated by an extended coiled-coil. The N-terminal head domain forms a mixed alpha–beta globular structure. Numerous factors interact with the C-terminus of the coiled-coil domain, which is also associated with significant self-association between XRCC4 dimers. A range of construct lengths of human XRCC4 were expressed and purified, and the 1–164 variant had the best NMR properties, as judged by consistent linewidths, and chemical shift dispersion. In this work we report the 1H, 15 N and 13C backbone resonance assignments of human XRCC4 in the solution form of the 1–164 construct. Assignments were obtained by heteronuclear multidimensional NMR spectroscopy. In total, 156 of 161 assignable residues of XRCC4 were assigned to resonances in the TROSY spectrum, with an additional 11 resonances assigned to His-Tag residues. Prediction of solution secondary structure from a chemical shift analysis using the TALOS + webserver is in good agreement with the published X-ray crystal structures of this protein.
    • A Bayesian Estimation of Child Labour in India

      Kim, Jihye; email: jihye.kim@postgrad.manchester.ac.uk; Olsen, Wendy; Wiśniowski, Arkadiusz (Springer Netherlands, 2020-06-18)
      Abstract: Child labour in India involves the largest number of children in any single country in the world. In 2011, 11.8 million children between the ages of 5 and 17 were main workers (those working more than 6 mo) according to the Indian Census. Our estimate of child labour using a combined-data approach is slightly higher than that: 13.2 million (11.4–15.2 million) for ages 5 to 17. There are various opinions on how best to measure the prevalence of child labour. In this study, we use the International Labour Organization (ILO)‘s methodology to define hazardousness and combine it with the most recent United Nations Children’s Fund (UNICEF)‘s time thresholds for economic work and household chores. The specific aims of this study are to estimate the prevalence of child labour in the age group 5 to 17 and to suggest a combined-data approach using Bayesian inference to improve the accuracy of the child labour estimation. This study combines the National Sample Survey on Employment and Unemployment 2011/12 and the India Human Development Survey 2011/12 and compares the result with the reported figures for the incidence of child labour from the Indian Census. Our unique combined-data approach provides a way to improve accuracy, smooth the variations between ages and provide reliable estimates of the scale of child labour in India.
    • Bifurcations of drops and bubbles propagating in variable-depth Hele-Shaw channels

      Thompson, Alice B.; orcid: 0000-0001-9558-1554; email: alice.thompson@manchester.ac.uk (Springer Netherlands, 2021-07-18)
      Abstract: The steady propagation of air bubbles through a Hele-Shaw channel with either a rectangular or partially occluded cross section is known to exhibit solution multiplicity for steadily propagating bubbles, along with complicated transient behaviour where the bubble may visit several edge states or even change topology several times, before typically reaching its final propagation mode. Many of these phenomena can be observed both in experimental realisations and in numerical simulations based on simple Darcy models of flow and bubble propagation in a Hele-Shaw cell. In this paper, we investigate the corresponding problem for the propagation of a viscous drop (with viscosity ν relative to the surrounding fluid) using a Darcy model. We explore the effect of drop viscosity on the steady solution structure for drops in rectangular channels or with imposed height variations. Under the Darcy model in a uniform channel, steady solutions for bubbles map directly on to those for drops with any internal viscosity ν≠1. Hence, the solution multiplicity predicted for bubbles also occurs for drops, although for ν>1, the interface shape is reversed with inflection points appearing at the rear rather than the front of the drop. The equivalence between bubbles and drops breaks down for transient behaviour, at the introduction of any height variation, for multiple bodies of different viscosity ratios and for more detailed models which produce a more complicated flow in the interior of the drop. We show that the introduction of topography variations affects bubbles and drops differently, with very viscous drops preferentially moving towards more constricted regions of the channel. Both bubbles and drops can undergo transient behaviour which involves breakup into two almost equal bodies, which then symmetry break before either recombining or separating indefinitely.
    • Bifurcations of drops and bubbles propagating in variable-depth Hele-Shaw channels

      Thompson, Alice B.; orcid: 0000-0001-9558-1554; email: alice.thompson@manchester.ac.uk (Springer Netherlands, 2021-07-18)
      Abstract: The steady propagation of air bubbles through a Hele-Shaw channel with either a rectangular or partially occluded cross section is known to exhibit solution multiplicity for steadily propagating bubbles, along with complicated transient behaviour where the bubble may visit several edge states or even change topology several times, before typically reaching its final propagation mode. Many of these phenomena can be observed both in experimental realisations and in numerical simulations based on simple Darcy models of flow and bubble propagation in a Hele-Shaw cell. In this paper, we investigate the corresponding problem for the propagation of a viscous drop (with viscosity ν relative to the surrounding fluid) using a Darcy model. We explore the effect of drop viscosity on the steady solution structure for drops in rectangular channels or with imposed height variations. Under the Darcy model in a uniform channel, steady solutions for bubbles map directly on to those for drops with any internal viscosity ν≠1. Hence, the solution multiplicity predicted for bubbles also occurs for drops, although for ν>1, the interface shape is reversed with inflection points appearing at the rear rather than the front of the drop. The equivalence between bubbles and drops breaks down for transient behaviour, at the introduction of any height variation, for multiple bodies of different viscosity ratios and for more detailed models which produce a more complicated flow in the interior of the drop. We show that the introduction of topography variations affects bubbles and drops differently, with very viscous drops preferentially moving towards more constricted regions of the channel. Both bubbles and drops can undergo transient behaviour which involves breakup into two almost equal bodies, which then symmetry break before either recombining or separating indefinitely.
    • Cancellation of Tollmien–Schlichting waves with surface heating

      Brennan, Georgia S.; orcid: 0000-0002-4914-5716; Gajjar, Jitesh S. B.; orcid: 0000-0001-8744-0102; email: jitesh.gajjar@manchester.ac.uk; Hewitt, Richard E.; orcid: 0000-0003-3056-1346 (Springer Netherlands, 2021-04-22)
      Abstract: Two-dimensional boundary layer flows in quiet disturbance environments are known to become unstable to Tollmien–Schlichting waves. The experimental work of Liepmann et al. (J Fluid Mech 118:187–200, 1982), Liepmann and Nosenchuck (J Fluid Mech 118:201–204, 1982) showed how it is possible to control and reduce unstable Tollmien–Schlichting wave amplitudes using unsteady surface heating. We consider the problem of an oncoming planar compressible subsonic boundary layer flow with a three-dimensional vibrator mounted on a flat plate, and with surface heating present. It is shown using asymptotic methods based on triple-deck theory that it is possible to choose an unsteady surface heating distribution to cancel out the response due to the vibrator. An approximation based on the exact formula is used successfully in numerical computations to confirm the findings. The results presented here are a generalisation of the analogous results for the two-dimensional problem in Brennan et al. (J Fluid Mech 909:A16-1, 2020).
    • Climate and monetary policy: do temperature shocks lead to inflationary pressures?

      Mukherjee, K.; Ouattara, B.; orcid: 0000-0002-6336-1941; email: osman.ouattara@manchester.ac.uk (Springer Netherlands, 2021-08-10)
      Abstract: In the race towards economic growth, increased pollutant emissions have spurred the rise in global surface temperatures, intensifying the process of climate change. While the existing literature on the economic impact of climate-related variables has looked at outcomes such as growth, income, fiscal response, and poverty, the effect of temperature shocks on inflation has largely been neglected. This paper is an attempt to fill this lacuna. Indeed, we analyze the dynamic impact of temperature shocks on inflation, a key policy variable of most central banks. We use a panel-VAR method with fixed-effects and a sample of developed and developing countries over the period 1961–2014. Our results suggest that temperature shocks lead to inflationary pressures. Worryingly, and for developing countries in particular, we find that these effects persist several years after the initial shock. Our finding remained unaltered by various robustness checks. We show that these effects pose a threat to monetary policy making. We argue that central banks should pay more attention to temperature shocks.
    • Climate and monetary policy: do temperature shocks lead to inflationary pressures?

      Mukherjee, K.; Ouattara, B.; orcid: 0000-0002-6336-1941; email: osman.ouattara@manchester.ac.uk (Springer Netherlands, 2021-08-10)
      Abstract: In the race towards economic growth, increased pollutant emissions have spurred the rise in global surface temperatures, intensifying the process of climate change. While the existing literature on the economic impact of climate-related variables has looked at outcomes such as growth, income, fiscal response, and poverty, the effect of temperature shocks on inflation has largely been neglected. This paper is an attempt to fill this lacuna. Indeed, we analyze the dynamic impact of temperature shocks on inflation, a key policy variable of most central banks. We use a panel-VAR method with fixed-effects and a sample of developed and developing countries over the period 1961–2014. Our results suggest that temperature shocks lead to inflationary pressures. Worryingly, and for developing countries in particular, we find that these effects persist several years after the initial shock. Our finding remained unaltered by various robustness checks. We show that these effects pose a threat to monetary policy making. We argue that central banks should pay more attention to temperature shocks.
    • Coalitions and Public Action in the Reshaping of Corporate Responsibility: The Case of the Retail Banking Industry

      de la Cuesta-González, Marta; Froud, Julie; orcid: 0000-0002-8330-2615; email: julie.froud@manchester.ac.uk; Tischer, Daniel (Springer Netherlands, 2020-05-25)
      Abstract: This paper addresses the question of whether and how public action via civil society and/or government can meaningfully shape industry-wide corporate responsibility (ICR) behaviour. We explore how, in principle, ICR can come about and what conditions might be effective in promoting more ethical behaviour. We propose a framework to understand attempts to develop more responsible behaviour at an industry level through processes of negotiation and coalition building. We suggest that any attempt to meaningfully influence ICR would require stakeholders to possess both power and legitimacy; moreover, magnitude and urgency of the issue at stake may affect the ability to influence ICR. The framework is applied to the retail banking industry, focusing on post-crisis experiences in two countries—Spain and the UK—where there has been considerable pressure on the retail banking industry by civil society and/or government to change behaviours, especially to abandon unethical practices. We illustrate in this paper how corporate responsibility at the sector level in retail banking is the product of context-specific processes of negotiation between civil society and public authorities, on behalf of customers and other stakeholders, drawing on legal and other institutions to influence industry behaviour.
    • Corporate Law Versus Social Autonomy: Law as Social Hazard

      Galanis, Michael; email: michael.galanis@manchester.ac.uk (Springer Netherlands, 2020-05-26)
      Abstract: This article argues that corporate law has become the legal platform upon which is erected a social process impeding society’s capacity to lucidly reflect on its primary ends; in this sense, corporate law is in conflict with social autonomy. This process is described here as a social feedback loop, in the structural centre of which lies the corporation which imposes its own purpose as an irrational social end, i.e. irrespective of its potentially catastrophic social consequences. The article argues that resolving the conflict between corporate law and social autonomy is impossible, because it presupposes a change of social paradigm towards one where corporate law as business organisation law has no obvious fit. This questions the social legitimacy of corporate law, signifies its non-permanence and thus opens up the field for seeking radical alternatives in the future.
    • Damage Detection in Composites By Artificial Neural Networks Trained By Using in Situ Distributed Strains

      Califano, America; orcid: 0000-0002-6344-8051; email: america.califano@gmail.com; email: america.califano@unicampania.it; Chandarana, Neha; Grassia, Luigi; D’Amore, Alberto; Soutis, Constantinos; email: constantinos.soutis@manchester.ac.uk (Springer Netherlands, 2020-08-07)
      Abstract: In this paper, a passive structural health monitoring (SHM) method capable of detecting the presence of damage in carbon fibre/epoxy composite plates is developed. The method requires the measurement of strains from the considered structure, which are used to set up, train, and test artificial neural networks (ANNs). At the end of the training phase, the networks find correlations between the given strains, which represent the ‘fingerprint’ of the structure under investigation. Changes in the distribution of these strains is captured by assessing differences in the previously identified strain correlations. If any cause generates damage that alters the strain distribution, this is considered as a reason for further detailed structural inspection. The novelty of the strain algorithm comes from its independence from both the choice of material and the loading condition. It does not require the prior knowledge of material properties based on stress-strain relationships and, as the strain correlations represent the structure and its mechanical behaviour, they are valid for the full range of operating loads. An implementation of such approach is herein presented based on the usage of a distributed optical fibre sensor that allows to obtain strain measurement with an incredibly high resolution.
    • DP structure and internally headed relatives in Washo

      Hanink, Emily A.; email: emily.hanink@manchester.ac.uk (Springer Netherlands, 2020-07-17)
      Abstract: This paper contributes to recent lines of inquiry addressing the nature of indices in definite expressions. The primary language of investigation is Washo, a North American isolate spoken in the western United States. Building on previous claims about the structure of anaphoric definites, I propose a unified analysis of the Washo DP that lends novel evidence to the claim that indices are best thought of as syntactic objects in their own right, independent from D. The structurally encoded index—introduced by a head idx—is shown to be overtly realized by the morpheme gi/ge in both pronouns and demonstratives, as well as at the periphery of internally headed relative clauses, which are themselves complex DPs. An important aspect of this proposal is the argument that idx can play two related semantic roles: The semantic index it hosts can be interpreted either as a variable, as previously proposed for familiar definites, or itself as a variable binder. The availability of the latter explains the appearance of gi/ge in internally headed relatives. I show moreover that the exponence of idx in Washo is sensitive to the type of complement it takes, a proposal that makes sense of the observed distribution of gi/ge in a range of definite expressions.
    • Epidemiology is ecosystem science

      Lee, Keekok; orcid: 0000-0001-8400-9990; email: keekok.lee@manchester.ac.uk (Springer Netherlands, 2019-02-26)
      Abstract: This paper primarily argues that Epidemiology is Ecosystem Science. It will not only explore this notion in detail but will also relate it to the argument that Classical Chinese Medicine was/is Ecosystem Science. Ecosystem Science (as instantiated by Epidemiology) and Ecosystem Science (as instantiated by Classical Chinese Medicine) share these characteristics: (a) they do not subscribe to the monogenic conception of disease; (b) they involve multi variables; (c) the model of causality presupposed is multi-factorial as well as non-linear.
    • Epistemic Injustice and the Attention Economy

      Smith, Leonie; orcid: 0000-0002-5073-4294; email: L.smith@manchester.ac.uk; Archer, Alfred; orcid: 0000-0001-9398-6427 (Springer Netherlands, 2020-09-05)
      Abstract: In recent years, a significant body of literature has emerged on the subject of epistemic injustice: wrongful harms done to people in their capacities as knowers (Fricker 2007). Up to now this literature has ignored the role that attention has to play in epistemic injustice. This paper makes a first step towards addressing this gap. We argue that giving someone less attention than they are due, which we call an epistemic attention deficit, is a distinct form of epistemic injustice. We begin by outlining what we mean by epistemic attention deficits, which we understand as a failure to pay someone the attention they are due in their role as an epistemic agent. We argue that these deficits constitute epistemic injustices for two reasons. First, they affect someone’s ability to influence what others believe. Second, they affect one’s ability to influence the shared common ground in which testimonial exchanges take place. We then outline the various ways in which epistemic attention deficits harm those who are subject to them. We argue that epistemic attention deficits are harms in and of themselves because they deprive people of an essential component of epistemic agency. Moreover, epistemic attention deficits reduce an agent’s ability to participate in valuable epistemic practices. These two forms of harm have important impacts on educational performance and the distribution of resources. Finally, we argue that epistemic attention deficits both hinder and shape the development of epistemic agency. We finish by exploring some practical implications arising from our discussion.
    • EVI1 oncoprotein expression and CtBP1-association oscillate through the cell cycle

      Paredes, Roberto; Schneider, Marion; Pearson, Stella; Teng, Hsiang Yin; Kelly, James R.; Pierce, Andrew; Somervaille, Tim C. P.; Whetton, Anthony D.; Meyer, Stefan; orcid: 0000-0002-2283-3690; email: stefan.meyer@manchester.ac.uk (Springer Netherlands, 2020-09-26)
      Abstract: Aberrantly high expression of EVI1 in acute myeloid leukaemia (AML) is associated with poor prognosis. For targeted treatment of EVI1 overexpressing AML a more detailed understanding of aspects of spatiotemporal interaction dynamics of the EVI1 protein is important. EVI1 overexpressing SB1690CB AML cells were used for quantification and protein interaction studies of EVI1 and ΔEVI1. Cells were cell cycle-synchronised by mimosine and nocodazole treatment and expression of EVI1 and related proteins assessed by western blot, immunoprecipitation and immunofluorescence. EVI1 protein levels oscillate through the cell cycle, and EVI1 is degraded partly by the proteasome complex. Both EVI1 and ΔEVI1 interact with the co-repressor CtBP1 but dissociate from CtBP1 complexes during mitosis. Furthermore, a large fraction of EVI1, but not ΔEVI1 or CtBP1, resides in the nuclear matrix. In conclusion, EVI1- protein levels and EVI1-CtBP1 interaction dynamics vary though the cell cycle and differ between EVI1 and ΔEVI1. These data ad to the functional characterisation of the EVI1 protein in AML and will be important for the development of targeted therapeutic approaches for EVI1-driven AML.
    • Exploratory study of the association in the United Kingdom between hypertension and inorganic arsenic (iAs) intake from rice and rice products

      Xu, Lingqian; Polya, David A.; email: david.polya@manchester.ac.uk (Springer Netherlands, 2020-04-28)
      Abstract: Hypertension risks arising from chronic exposure to inorganic arsenic (iAs) are well documented. Consumption of rice is a major iAs exposure route for over 3 billion people; however, there is a lack of epidemiological evidence demonstrating an association of hypertension risks with iAs intake from rice, especially in areas where there is little exposure from drinking water but a growing demand for rice intake. To address this, we conducted an individual-level cross-sectional analysis to quantify the extent to which daily iAs intake from rice and rice products (E-iAsing,rice) modifies the association between hypertension risks and previously well-established risk factors. The analysis was based on secondary dietary, socio-demographic and health status data of 598 participants recorded in the UK National Diet and Nutrition Survey 2014–2016. E-iAsing,rice and five blood pressure endpoints were derived with potential associations explored through generalized linear models. According to the results, a negative but not significant relationship was found between hypertension risks and E-iAsing,rice after adjusting for major risk factors, notably age, gender, diabetes and obesity, with relatively higher risks being observed for male, middle-aged, overweight, alcohol consumer or Asian or Asian British, Black or Black British and mixed ethnic groups. Though inconclusive and mainly limited by potential incomplete adjustment for major confounders and intrinsic disadvantages of a cross-sectional design, this study was the first quantifying the individual level dose–response relationship between E-iAsing,rice and hypertension risks and is consistent with previous studies on the limited associations of hypertension with low-level arsenic exposure from drinking water. Larger scale cohort studies are indicated to quantify the association but in any event it is likely to be weak.
    • Fire Safety Assessment of Epoxy Composites Reinforced by Carbon Fibre and Graphene

      Zhang, Qiangjun; orcid: 0000-0002-3969-7090; email: qiangjun.zhang@manchester.ac.uk; Wang, Yong C; Soutis, Constantinos; Bailey, Colin G.; Hu, Yuan (Springer Netherlands, 2020-07-14)
      Abstract: This paper presents a coupled numerical investigation to assess the reaction to fire performance and fire resistance of various types of epoxy resin (ER) based composites. It examines the fire response of carbon fibre (CF) reinforced ER (CF/ER), ER with graphene nanoplatelets (GNP/ER) and CF reinforced GNP/ER (CF/GNP/ER). Thermal, physical and pyrolysis properties are presented to assist numerical modelling that is used to assess the material ability to pass the regulatory vertical burn test for new aircraft structures and estimate in-fire and post-fire residual strength properties. Except for the CF/GNP/ER composite, all other material systems fail the vertical burn test due to continuous burning after removal of the fire source. Carbon fibres are non-combustible and therefore reduce heat release rate of the ER composite. By combining this property with the beneficial barrier effects of graphene platelets, the CF/GNP/ER composite with 1.5 wt% GNP and 50 wt% CF self-extinguishes within 15 s after removal of the burner with a relatively small burn length. Graphene drastically slows down heat conduction and migration of decomposed volatiles to the surface by creating improved char structures. Thus, graphene is allowing the CF/GNP/ER composite panel to pass the regulatory vertical burn test. Due to low heat conduction and reduced heat release rate, the maximum temperatures in the CF/GNP/ER composite are low so the composite material retains very high in-fire and post-fire mechanical properties, maintaining structural integrity. In contrast, temperatures in the CF/ER composite are much higher. At a maximum temperature of 86 °C, the residual in-fire tensile and compressive mechanical strengths of CF/GNP/ER are about 87% and 59% respectively of the ambient temperature values, compared to 70% and 21% respectively for the CF/ER composite that has a temperature of 140 °C at the same time (but the CF/ER temperature will be higher due to continuing burning). Converting mass losses of the composites into char depth, the post-fire mechanical properties of the CF/GNP/ER composite are about 75% of the ambient condition compared to about 68% for the CF/ER composite.
    • Geochemical compositional controls on DNA strand breaks induced in in vitro cell-free assays by crushed rock powders from the Panasqueira mine area, Portugal

      Badri, Hatim; Polya, David A.; orcid: 0000-0002-7484-6696; email: david.polya@manchester.ac.uk; Povey, Andrew. C. (Springer Netherlands, 2020-07-09)
      Abstract: DNA strand breaks are a common form of DNA damage that can contribute to chromosomal instability or gene mutations. Such strand breaks may be caused by exposure to heavy metals. The aim of this study was to assess the level of DNA strand breaks caused by µm-scale solid particles of known chemical composition with elevated heavy metals/metalloids, notably arsenic, using an in vitro cell-free DNA plasmid scission assay. These samples were incubated with and without H2O2 to see whether damage occurs directly or indirectly through the Fenton reaction. Levels of DNA damage in the absence of H2O2 were < 10%, but in the presence of H2O2, all samples showed higher levels of damage ranging from 10 to 100% suggesting that damage was being incurred through the Fenton reaction. Using bivariate correlation analysis and multiple linear regression, manganese oxide (MnO), sulphur (S), copper (Cu), and zinc (Zn) concentrations in the particulates were found to be the most significant predictors of DNA damage. The mechanism of this DNA damage formation has yet to be thoroughly investigated but is hypothesised to be due to reactive oxygen species formation. Further work is required to assess the extent of contribution of reactive oxygen species to this DNA damage, but this study highlights the potential role of chemistry and/or mineralogy to the extent and/or nature of DNA damage caused by particulates.
    • Geostatistical model of the spatial distribution of arsenic in groundwaters in Gujarat State, India

      Wu, Ruohan; Podgorski, Joel; Berg, Michael; Polya, David A.; orcid: 0000-0002-7484-6696; email: david.polya@manchester.ac.uk (Springer Netherlands, 2020-07-11)
      Abstract: Geogenic arsenic contamination in groundwaters poses a severe health risk to hundreds of millions of people globally. Notwithstanding the particular risks to exposed populations in the Indian sub-continent, at the time of writing, there was a paucity of geostatistically based models of the spatial distribution of groundwater hazard in India. In this study, we used logistic regression models of secondary groundwater arsenic data with research-informed secondary soil, climate and topographic variables as principal predictors generate hazard and risk maps of groundwater arsenic at a resolution of 1 km across Gujarat State. By combining models based on different arsenic concentrations, we have generated a pseudo-contour map of groundwater arsenic concentrations, which indicates greater arsenic hazard (> 10 μg/L) in the northwest, northeast and south-east parts of Kachchh District as well as northwest and southwest Banas Kantha District. The total number of people living in areas in Gujarat with groundwater arsenic concentration exceeding 10 μg/L is estimated to be around 122,000, of which we estimate approximately 49,000 people consume groundwater exceeding 10 µg/L. Using simple previously published dose–response relationships, this is estimated to have given rise to 700 (prevalence) cases of skin cancer and around 10 cases of premature avoidable mortality/annum from internal (lung, liver, bladder) cancers—that latter value is on the order of just 0.001% of internal cancers in Gujarat, reflecting the relative low groundwater arsenic hazard in Gujarat State.
    • Impact Response of Curved Composite Laminates: Effect of Radius and Thickness

      Harris, William; orcid: 0000-0002-5775-2428; email: william.harris-4@postgrad.manchester.ac.uk; Soutis, Constantinos; email: constantinos.soutis@manchetser.ac.uk; Atkin, Christopher (Springer Netherlands, 2020-07-25)
      Abstract: This paper presents the results of drop-weight impact testing (5 J to 30 J) on curved ±55° E-glass-epoxy laminates of varying radii and wall thickness. Three radii (75 mm, 100 mm, and 125 mm) on laminates with an effective wall thickness of 2.5 mm, and three wall thicknesses (2.5 mm, 4.1 mm, and 6.6 mm) with a radius of 100 mm were investigated. The damage pattern remained consistent, with the exception of the damage area, across the tested energies and was dominated by internal matrix cracking and multiple delaminations. However, no damage was recorded following a 5 J impact on the 2.5 mm thick laminates with 100 mm and 125 mm radii, all energy was absorbed elastically, while the laminate with a 75 mm radius of curvature developed a damage area of over 80 mm2. The thicker laminates showed a reduced overall damage area but a greater number of delaminations. The relationship between laminate thickness and delamination threshold load was found to be in line with impact testing of flat plates, varying with the laminate thickness to the 3/2 power. However, the simplified beam theory and a fracture mechanics model developed for the prediction of delamination threshold of flat plates was found to underestimate the delamination threshold load (DTL) of the curved laminates studied by about 40%. An increase in the laminate’s flexural modulus of a factor of two is required to bring the model’s predictions in line with the DTL values measured experimentally, highlighting how curvature can enhance bending stiffness and alter damage evolution. Finally, a significant finding is that the DTL of the curved plates is around 15% lower than the value measured for the whole cylindrical pipe of same specifications. Testing curved sections rather than a whole pipe could reduce effort, but further work is required to confirm this statement.
    • Influence of biological origin on the tensile properties of cellulose nanopapers

      Kontturi, Katri S.; Lee, Koon-Yang; Jones, Mitchell P.; Sampson, William W.; email: william.sampson@manchester.ac.uk; Bismarck, Alexander; email: alexander.bismarck@univie.ac.at; Kontturi, Eero; orcid: 0000-0003-1690-5288; email: eero.kontturi@aalto.fi (Springer Netherlands, 2021-05-22)
      Abstract: Cellulose nanopapers provide diverse, strong and lightweight templates prepared entirely from sustainable raw materials, cellulose nanofibers (CNFs). Yet the strength of CNFs has not been fully capitalized in the resulting nanopapers and the relative influence of CNF strength, their bonding, and biological origin to nanopaper strength are unknown. Here, we show that basic principles from paper physics can be applied to CNF nanopapers to illuminate those relationships. Importantly, it appeared that ~ 200 MPa was the theoretical maximum for nanopapers with random fibril orientation. Furthermore, we demonstrate the contrast in tensile strength for nanopapers prepared from bacterial cellulose (BC) and wood-based nanofibrillated cellulose (NFC). Endemic amorphous polysaccharides (hemicelluloses) in NFC act as matrix in NFC nanopapers, strengthening the bonding between CNFs just like it improves the bonding between CNFs in the primary cell wall of plants. The conclusions apply to all composites containing non-woven fiber mats as reinforcement. Graphic abstract: