• Advances in Microstructural Understanding of Wrought Aluminum Alloys

      Robson, J. D.; email: joseph.d.robson@manchester.ac.uk; Engler, O.; Sigli, C.; Deschamps, A.; Poole, W. J. (Springer US, 2020-07-08)
      Abstract: Wrought aluminum alloys are an attractive option in the quest for lightweight, recyclable, structural materials. Modern wrought aluminum alloys depend on control of complex microstructures to obtain their properties. This requires an understanding of the coupling between alloy composition, processing, and microstructure. This paper summarizes recent work to understand microstructural evolution in such alloys, utilizing the advanced characterization techniques now available such as atom probe tomography, high-resolution electron microscopy, and synchrotron X-ray diffraction and scattering. New insights into precipitation processes, deformation behavior, and texture evolution are discussed. Recent progress in predicting microstructural evolution using computer modeling is also summarized.
    • Application of Imaging Techniques to Determine the Post-Yield Behaviour of the Heterogeneous Microstructure of Friction Stir Welds

      Ramachandran, S.; orcid: 0000-0002-6881-2940; email: s.ramachandran@manchester.ac.uk; Lakshminarayanan, A. K.; Reed, P. A. S.; Dulieu-Barton, J. M. (Springer US, 2021-04-21)
      Abstract: Background: Friction Stir Welding (FSW) causes intense plastic deformation and consequent thermomechanical interactions resulting in a localised heterogeneous microstructure. To understand the weld mechanical behaviour, it is necessary to identify each microstructural sub-region in the weld. Objective: Determine the relationship between the local microstructure and mechanical behaviour of the different microstructural regions in a FSW. Methods: Scanning electron microscopy (SEM) identified the microstructural sub-regions of an FSW joint. A novel High-Resolution Digital Image Correlation (HR-DIC) methodology enabled the determination of full-field strain response to provide the mechanical behaviour of the FSW sub-regions. X-ray computed tomography (CT) identified the geometry of the FSW and material composition. Results: The grain morphology in the FSW varied in the stir zone with a fine grain structure in the weld nugget and larger grains in the thermomechanical affected zone (TMAZ); the grains were larger in the retreating side (RS) compared to the advancing side (AS). Tungsten deposits were found in the weld nugget and attributed to tool wear. The mechanical properties of the weld subregions showed that the material in the stir zone had a greater yield strength than the base material and the RS of the FSW was much more ductile than the weld nugget and the AS side. The tungsten distributions in the stir zone correlated with the local mechanical behaviour. Conclusions: A novel methodology is developed that combines microstructural observations with HR-DIC enabling, for the first time, the FSW sub-region mechanical behaviour, to be related to the local grain morphology and inclusions caused by tool wear.
    • Coping Style and Early Life Vocalizations in the Common Marmoset ( Callithrix jacchus )

      Díaz, Sergio; email: s.gonzalezdiaz@chester.ac.uk; Sánchez, Susana; Fidalgo, Ana (Springer US, 2020-05-20)
      Abstract: Coping styles describe behavioral differences during stressful or challenging situations. Coping styles are stable over time but little is known about early life manifestation and development of these behavioral differences. We aimed to investigate if differences in the way marmosets produce vocalizations at an early age are related to their coping style in the future. We studied 14 common marmosets (Callithrix jacchus) from three social groups housed at the marmoset colony at Universidad Autónoma de Madrid. We recorded the vocalizations of each marmoset in isolation at 15–17 days of age, analyzing latency to vocalize and calling rate of phee and tsik calls. To measure coping style, we introduced a novel stimulus to the group cages when infants were 3 months old and recorded exploration, headcocking, and approaches to the stimulus. The results showed negative relationships between the latency of phee call (a long-range contact call) at 15–17 days and frequency of exploration and approach to the novel stimulus at 3 months, although both correlations fall above the cut-off points for the false discovery rate. Marmosets that gave long-range calls sooner at 15–17 days of age also showed more exploratory behaviors at 3 months. The results also showed group differences in exploration at 3 months, and twins were more similar to each other than to other infants in the sample. There were no group differences in early vocalizations and no sex differences in any variable. These findings suggest that coping style is stable from as early as 15–17 days after birth and suggest that the group can influence exploration in marmosets.
    • Deformation Enhanced Diffusion in Aluminium Alloys

      Robson, J. D.; email: joseph.robson@manchester.ac.uk (Springer US, 2020-08-18)
      Abstract: Deformation introduces defects such as dislocations and excess vacancies that can strongly influence diffusion rates in aluminium alloys. This is of great importance in understanding the effect of deformation on processes such as precipitation hardening, which can be accelerated by orders of magnitude by the defects introduced. In this work, a simple and widely used classical model has been employed to explore the effect of process variables on diffusion enhancement due to deformation-induced excess vacancies and dislocations. It is demonstrated that in aluminium alloys, the strain rates and temperatures used in processing and testing encompass a range of regimes. At low strain rate or high temperature, a steady state becomes established in which the deformation enhancement depends on strain rate but not strain. Conversely, at high strain rate or low temperature, deformation enhancement is insensitive to strain rate but increases with strain. For all conditions, the effect of excess vacancies is much stronger than the direct effect of pipe diffusion along dislocations. The predicted deformation-induced vacancy concentration can exceed that expected after rapid quenching by an order of magnitude, but the lifetime of the deformation-induced vacancies is much shorter. Finally, limitations of the classical model and suggestions for improvement are proposed.
    • Enabling Dynamic System Integration on Maxeler HLS Platforms

      Kritikakis, Charalampos; email: charalampos.kritikakis@manchester.ac.uk; Koch, Dirk (Springer US, 2020-08-09)
      Abstract: High Level Synthesis (HLS) tools enable application domain experts to implement applications and algorithms on FPGAs. The majority of present FPGA applications is following a stream processing model which is almost entirely implemented statically and not exploiting the benefits enabled by partial reconfiguration. In this paper, we propose a generic approach for implementing and using partial reconfiguration through an HLS design flow for Maxeler platforms. Our flow extracts HLS generated HDL code from the Maxeler compilation process in order to implement a static FPGA infrastructure as well as run-time reconfigurable stream processing modules. As a distinct feature, our infrastructure can accommodate multiple partial modules in a pipeline daisy-chained manner, which aligns directly to Maxeler’s dataflow programming paradigm. The benefits of the proposed flow are demonstrated by a case study of a dynamically reconfigurable video processing pipeline delivering 6.4GB/s throughput.
    • Ensuring Risk Awareness of Vulnerable Patients in the Post- Montgomery Era: Treading a Fine Line

      Talukdar, Sandip; email: sandip.talukdar@gmail.com; email: sandip.talukdar@postgrad.manchester.ac.uk (Springer US, 2020-05-17)
      Abstract: The 2015 UK Supreme Court judgment in Montgomery v Lanarkshire reinforces the importance of informed consent to medical treatment. This paper suggests that Montgomery recognises the challenge faced by vulnerable individuals in choosing between treatment options and making decisions with appreciation of information about material risks. The judgment endorses a form of weak paternalism to safeguard such persons, which is not disrespectful of the aggregate principles of the Mental Capacity Act 2005. But ethical practice requires professionals to tread carefully between weak and hard paternalism in the context of therapeutic interactions with vulnerable patients, while ensuring their awareness of material risks.
    • Exploring Staff Implementation of a Self-directed Parenting Intervention for Parents with Mental Health Difficulties

      Butler, J.; Gregg, L.; Calam, R.; Wittkowski, A.; orcid: 0000-0003-3806-0183; email: anja.wittkowski@manchester.ac.uk (Springer US, 2020-05-22)
      Abstract: Parents with mental health difficulties face significant barriers in accessing evidence-based parenting interventions. Self-directed approaches may be a destigmatising, accessible alternative. Evidence has suggested that Triple P Positive Parenting Programme’s self-directed format is as effective as more time- and cost-intensive delivery methods. The aim of the current study was to establish whether staff were able to use this intervention with parents with mental health difficulties and to explore staff experiences of implementation. Triple P self-help workbooks were provided to practitioners across three teams. Data were collected regarding workbook uptake and use. Interviews with staff exploring their experiences of implementation were analysed using thematic analysis. Overall, 41 participants were recruited, of which 12 (29.27%) also consented to interviews. Overall, six practitioners (14.63%) reported that they utilised the workbook. Uptake and utilisation were varied, but practitioners who used the workbook reported positive outcomes. Interviews revealed themes regarding practitioner concerns, views of the intervention and implementation issues. Self-directed Triple remains a promising intervention but its feasibility is dependent on addressing barriers to implementation and facilitating a family-focused approach to meet the needs of these parents and their children.
    • Hierarchical porous poly( l -lactic acid)/SiO 2 nanoparticles fibrous membranes for oil/water separation

      Lu, Zihan; orcid: 0000-0001-9835-4015; Zia, Qasim; Meng, Jinmin; Liu, Ting; Song, Jun; Li, Jiashen; email: jiashen.li@manchester.ac.uk (Springer US, 2020-09-02)
      Abstract: A two-step strategy has been developed to introduce silica nanoparticles into highly porous poly(l-lactic acid) (PLLA) nanofibers. Silica nanoparticles (SiNPs) were firstly synthesized and then modified to be hydrophobic. After PLLA/SiNPs composite fibrous membranes were electrospun and collected, they were re-crystallized by acetone at room temperature for a few minutes. With the re-arrangement of PLLA chains, the nano-/micro-electrospun fibres were transformed from non-porous ones to be porous ones with high surface area. Consequently, SiNPs that were completely covered by PLLA before acetone treatment showed up at the fibre surface. Higher PLLA crystallization also enhanced the Young’s modulus and tensile strength (420 and 8.47 MPa) of the composite membrane. However, incorporation of SiNPs into porous PLLA membranes reduced their modulus and tensile strength (280.66 and 5.92 MPa), but an increase in strain to fracture (80.82%) was observed. Scanning electron microscopy (SEM), focused ion beam SEM, transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction were applied to confirm the presence of SiNP in PLLA fibres. The presence of SiNPs inside and outside fibres enhances the hydrophobicity of PLLA/SiNPs nano-fibrous membrane as the water contact angle is greater than 150°. The oil absorption of these porous composite membranes was also tested using four different oils, which can reach the highest absorption capacity when the weight ratio of PLLA and SiNPs is 1:1. The flux of prepared membranes was investigated, and results indicated that SiNPs-loaded membrane effectively enhanced the flux (5200 Lm−2 h−1).
    • Higher Order Time Stepping Methods for Subdiffusion Problems Based on Weighted and Shifted Grünwald–Letnikov Formulae with Nonsmooth Data

      Wang, Yanyong; Yan, Yuyuan; Yan, Yubin; email: y.yan@chester.ac.uk; Pani, Amiya K. (Springer US, 2020-05-19)
      Abstract: Two higher order time stepping methods for solving subdiffusion problems are studied in this paper. The Caputo time fractional derivatives are approximated by using the weighted and shifted Grünwald–Letnikov formulae introduced in Tian et al. (Math Comput 84:2703–2727, 2015). After correcting a few starting steps, the proposed time stepping methods have the optimal convergence orders O(k2) and O(k3), respectively for any fixed time t for both smooth and nonsmooth data. The error estimates are proved by directly bounding the approximation errors of the kernel functions. Moreover, we also present briefly the applicabilities of our time stepping schemes to various other fractional evolution equations. Finally, some numerical examples are given to show that the numerical results are consistent with the proven theoretical results.
    • How materials can beat a virus

      Jones, Samuel T.; email: samuel.jones-4@manchester.ac.uk (Springer US, 2020-05-12)
    • Investigations of Hydrocarbon Species on Solid Catalysts by Inelastic Neutron Scattering

      Lin, Longfei; Mei, Qingqing; Han, Xue; Parker, Stewart F.; email: stewart.parker@stfc.ac.uk; Yang, Sihai; orcid: 0000-0002-1111-9272; email: Sihai.Yang@manchester.ac.uk (Springer US, 2020-10-26)
      Abstract: The status of surface species on solid catalysts during heterogeneous catalysis is often mysterious. Investigations of these surface species are crucial to deconvolute the reaction network and design more efficient catalysts. Vibrational spectroscopy is a powerful technique to study the interactions between surface species and the catalysts and infrared (IR) and Raman spectroscopies have been widely applied to study reaction mechanisms in heterogeneous catalysis. However, IR/Raman spectra are difficult to model computationally and important vibrational modes may be IR-, Raman- (or both) inactive due to restrictions by optical selection rules. Inelastic neutron scattering (INS) is another form of vibrational spectroscopy and relies on the scattering of neutrons by the atomic nucleus. A consequence of this is that INS is not subject to any optical selection rules and all vibrations are measurable in principle. INS spectroscopy has been used to investigate surface species on catalysts in a wide range of heterogeneous catalytic reactions. In this mini-review, we focus on applications of INS in two important fields: petrochemical reactions and C1 chemistry. We introduce the basic principles of the INS technique, followed by a discussion of its application in investigating two key catalytic systems: (i) the behaviour of hydrocarbons on metal-oxide and zeolite catalysts and (ii) the formation of hydrocarbonaceous species on methane reforming and Fischer–Tropsch catalysts. The power of INS in studying these important catalytic systems is demonstrated.
    • Investigations of Hydrocarbon Species on Solid Catalysts by Inelastic Neutron Scattering

      Lin, Longfei; Mei, Qingqing; Han, Xue; Parker, Stewart F.; email: stewart.parker@stfc.ac.uk; Yang, Sihai; orcid: 0000-0002-1111-9272; email: Sihai.Yang@manchester.ac.uk (Springer US, 2020-10-26)
      Abstract: The status of surface species on solid catalysts during heterogeneous catalysis is often mysterious. Investigations of these surface species are crucial to deconvolute the reaction network and design more efficient catalysts. Vibrational spectroscopy is a powerful technique to study the interactions between surface species and the catalysts and infrared (IR) and Raman spectroscopies have been widely applied to study reaction mechanisms in heterogeneous catalysis. However, IR/Raman spectra are difficult to model computationally and important vibrational modes may be IR-, Raman- (or both) inactive due to restrictions by optical selection rules. Inelastic neutron scattering (INS) is another form of vibrational spectroscopy and relies on the scattering of neutrons by the atomic nucleus. A consequence of this is that INS is not subject to any optical selection rules and all vibrations are measurable in principle. INS spectroscopy has been used to investigate surface species on catalysts in a wide range of heterogeneous catalytic reactions. In this mini-review, we focus on applications of INS in two important fields: petrochemical reactions and C1 chemistry. We introduce the basic principles of the INS technique, followed by a discussion of its application in investigating two key catalytic systems: (i) the behaviour of hydrocarbons on metal-oxide and zeolite catalysts and (ii) the formation of hydrocarbonaceous species on methane reforming and Fischer–Tropsch catalysts. The power of INS in studying these important catalytic systems is demonstrated.
    • Invited viewpoint: teaching programming to students in physical sciences and engineering

      Cawthorne, Lloyd; orcid: 0000-0002-3373-5682; email: lloyd.cawthorne@manchester.ac.uk (Springer US, 2021-08-05)
      Abstract: Computer programming is a key component of any physical science or engineering degree and is a skill sought by employers. Coding can be very appealing to these students as it is logical and another setting where they can solve problems. However, many students can often be reluctant to engage with the material as it might not interest them or they might not see how it applies to their wider study. Here, I present lessons I have learned and recommendations to increase participation in programming courses for students majoring in the physical sciences or engineering. The discussion and examples are taken from my second-year core undergraduate physics module, Introduction to Programming for Physicists, taught at The University of Manchester, UK. Teaching this course, I have developed successful solutions that can be applied to undergraduate STEM courses.
    • Latent Class Analysis of Mental Health in Middle Childhood: Evidence for the Dual-Factor Model

      Petersen, Kimberly J.; orcid: 0000-0002-4941-6897; email: kimberly.petersen@manchester.ac.uk; Humphrey, Neil; orcid: 0000-0002-8148-9500; Qualter, Pamela; orcid: 0000-0001-6114-3820 (Springer US, 2020-07-25)
      Abstract: Mental health is complex, comprising both mental distress and well-being. This study used latent class analysis to identify common combinations of mental distress and well-being (‘mental health classes’) among schoolchildren aged 8–9 years (N = 3340). Thirteen items, measuring a range of conduct problems, emotional symptoms, and subjective well-being, were included in the analysis. Four mental health classes were identified: (1) complete mental health (n = 1895, 57%), (2) vulnerable (n = 434, 13%), (3) emotional symptoms but content (n = 606, 18%), and (4) conduct problems but content (n = 404, 12%). The classes were reliably identified across different datasets, and for males and females. Differential relations with covariates indicated that mental health classes were distinct and externally valid. The results supported the dual-factor model of mental health, suggesting that mental distress and subjective well-being are separate continua. Three of the four possible combinations of high and low distress and subjective well-being posited by the dual-factor model were found using this inductive statistical method. Importantly, our analysis also revealed two ‘symptomatic but content’ groups, differentiated by symptom domain (internalising/externalising). The covariate analyses between mental health classes and sociodemographic factors, prior academic attainment, school connectedness, and peer support, indicated that there are nuanced relations between those variables and particular constellations of mental distress and well-being. As one of the few dual-factor studies to focus on middle childhood, the current study adds important new evidence that contributes to our understanding of the complexities of mental health among schoolchildren.
    • Maximum on a random time interval of a random walk with infinite mean

      Denisov, Denis; orcid: 0000-0003-0025-7140; email: denis.denisov@manchester.ac.uk (Springer US, 2020-06-23)
      Abstract: Let ξ1, ξ2, … be independent, identically distributed random variables with infinite mean E[|ξ1|]=∞. Consider a random walk Sn=ξ1+⋯+ξn, a stopping time τ=min{n≥1:Sn≤0} and let Mτ=max0≤i≤τSi. We study the asymptotics for P(Mτ>x), as x→∞.
    • Parental Licensing as Harm Reduction

      Shields, Liam; orcid: 0000-0001-9272-1937; email: liam.shields@manchester.ac.uk (Springer US, 2020-10-17)
      Abstract: In this paper, I will argue that some prominent objections to parental licensing rely on dubious claims about the existence of a very stringent, if not indefeasible, right to parent, which would be violated by licensing. I claim that attaching such stringency to the right only makes sense if we make a number of idealising assumptions. Otherwise, it is deeply implausible. Instead, I argue that we should evaluate parental licensing policies in much the same way we would harm reduction policies. By adopting this critical perspective, we can see that there are powerful, but quite different, reasons to be cautious about parental licensing relating to our ability to minimize the harmful effects of mass-parenting in a world of minimal surveillance and intervention.
    • Quantized Vortex Rings and Loop Solitons

      Green, P. J.; Grant, M. J.; Nevin, J. W.; Walmsley, P. M.; email: paul.walmsley@manchester.ac.uk; Golov, A. I.; orcid: 0000-0002-7244-5899 (Springer US, 2020-08-29)
      Abstract: The vortex filament model is used to investigate the interaction of a quantized vortex ring with a straight vortex line and also the interaction of two solitons traveling in opposite directions along a vortex. When a ring reconnects with a line, we find that a likely outcome is the formation of a loop soliton. When they collide, loop solitons reconnect as they overlap each other producing either one or two vortex rings. These simulations are relevant for experiments on quantum turbulence in the zero temperature limit where small vortex rings are expected to be numerous. It seems that loop solitons might also commonly occur on vortex lines as they act as transient states between the absorption of a vortex ring before another ring is emitted when the soliton is involved in a reconnection.
    • Social Network Analysis of a Chimpanzee ( Pan troglodytes ) Group in Captivity Following the Integration of a New Adult Member

      Díaz, Sergio; email: s.gonzalezdiaz@chester.ac.uk; Murray, Lindsay; Roberts, Sam G. B.; Rodway, Paul (Springer US, 2020-10-10)
      Abstract: Management of primates in captivity often presents the challenge of introducing new individuals into a group, and research investigating the stability of the social network in the medium term after the introduction can help inform management decisions. We investigated the behavior of a group of chimpanzees (Pan troglodytes) housed at Chester Zoo, UK over 12 months (divided into three periods of 4 months) following the introduction of a new adult female. We recorded grooming, proximity, other affiliative behaviors, and agonistic behaviors and used social network analysis to investigate the stability, reciprocity, and structure of the group, to examine the effect of rearing history on grooming network position and the role of sex in agonistic behavior. Both the grooming and agonistic networks correlated across all three periods, while affiliative networks correlated only between periods 2 and 3. Males had significantly higher out-degree centrality in agonistic behaviors than females, indicating that they carried out agonistic behaviors more often than females. There was no significant difference in centrality between hand-reared and mother-reared chimpanzees. Overall, the group structure was stable and cohesive during the first year after the introduction of the new female, suggesting that this change did not destabilize the group. Our findings highlight the utility of social network analysis in the study of primate sociality in captivity, and how it can be used to better understand primate behavior following the integration of new individuals.
    • The Fidelity of Training in Behaviour Change Techniques to Intervention Design in a National Diabetes Prevention Programme

      Hawkes, Rhiannon E.; orcid: 0000-0003-0479-8163; Cameron, Elaine; orcid: 0000-0002-8959-5148; Miles, Lisa M.; orcid: 0000-0002-8971-125X; French, David P.; orcid: 0000-0002-7663-7804; email: David.French@manchester.ac.uk (Springer US, 2021-02-09)
      Abstract: Background: The National Health Service Diabetes Prevention Programme (NHS-DPP) is a behavioural intervention for people identified as high risk for developing type 2 diabetes that has been rolled out across England. The present study evaluates whether the four commercial providers of the NHS-DPP train staff to deliver behaviour change technique (BCT) content with fidelity to intervention plans. Method: One set of mandatory training courses across the four NHS-DPP providers (seven courses across 13 days) was audio-recorded, and all additional training materials used were collected. Recordings and training materials were coded for BCT content using the BCT Taxonomy v1. BCTs and depth of training (e.g. instruction, demonstration, practice) of BCT content was checked against providers’ intervention plans. Results: Ten trainers and 78 trainees were observed, and 12 documents examined. The number of unique BCTs in audio recordings and associated training materials ranged from 19 to 44 across providers, and staff were trained in 53 unique BCTs across the whole NHS-DPP. Staff were trained in 66% of BCTs that were in intervention plans, though two providers trained staff in approximately half of BCTs to be delivered. The most common way that staff were trained in BCT delivery was through instruction. Training delivery style (e.g. experiential versus educational) varied between providers. Conclusion: Observed training evidences dilution from providers’ intervention plans. NHS-DPP providers should review their training to ensure staff are trained in all key intervention components, ensuring thorough training of BCTs (e.g. demonstrating and practicing how to deliver) to enhance BCT delivery.