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Microstructural Evolution and Property Evaluation of In Situ Al–MgAl2O4 Nanocomposite Prepared by γ-Al2O3 and Ultrasonication-Assisted Impeller Mixing
Get PDFData Availability Statement: The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.In situ Al–MgAl2O4 nanocomposite billet is prepared by the reaction of γ-Al2O3 with molten Al and ultrasonication-assisted impeller mixing. The microstructure of the composite shows homogeneously distributed MgAl2O4 crystals alongside their clusters in the Al matrix. Microstructural analysis reveals MgAl2O4 crystals distributed from 20 nm to 4 μm in size. The hardness is found to vary within the composite from 50 Hv for the matrix to 140 Hv for the particle cluster regions. The grain size is reduced from 1000 μm in reference metal (commercially pure Al [CPAl]) to 100 μm in the composite. The compression strength of the composite is increased substantially and higher strain-hardening effect in comparison with Al is noticed in the compression test. The signatures of extensive plastic deformation such as dislocation pileups, deformed grains, grain boundary pinning, and so on are observed in the composite via transmission electron microscopy. Damping properties of as-cast composite are higher than those of CPAl in the temperature range from room temperature (RT) to 350 °C. After rolling the composite, the damping capacity (Tanδ) of the composite is found to increase marginally after 150 °C. Higher damping is found to reoccur after the annealing treatment of the composite.European Commission in the 7th Framework Programme. Grant Number: FP7-NMP3-LA-2012-280421
Synergistic effect o f hydration and carbonation on the development of MgO-based cementitious materials
Get PDFThis thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonPortland cement (PC) production is accountable for 5-8% of anthropogenic
carbon dioxide (CO2) emissions. The concrete and construction industries
have been under increasing pressure to develop alternative materials and
technologies that produce fewer CO2 emissions and potentially absorb CO2,
resulting in an increased interest in sustainable practices. Compared to
cement clinker, reactive MgO (RM) from calcining MgCO3 has a lower
calcination temperature (700–900 °C vs. 1450 °C needed for calcining
CaCO3). It can gain strength by permanently sequestering CO2, and it can be
largely recycled after completing its lifecycle. This thesis investigates four
major aspects related to using reactive magnesia in the construction industry:
(1) Enhancement of carbon sequestration and mechanical properties of
reactive magnesia-based cements under 15% of CO2 and ambient curing; (2)
The effectiveness of amino acids on controlling performance of magnesiumbased
carbonate; (3) The feasibility of using magnesium-based carbonate in
Portland metakaolin cement blends; and (4) The role of magnesia in
alumina/silicate hydrate binder systems.
The first and second investigations (i.e. Chapter 4) involved the evaluation of
the influence of amino acids (i.e. L-arginine (L-Arg) and L-aspartic (L-Asp)) on
the performance of reactive magnesia-based mixes. The results of this
research were presented in terms of hardened properties such as bulk density
and compressive strength. The mechanisms of hydration and carbonation and
microstructural characterization of the mixes were also studied. The results
revealed that the use of amino acids as additives resulted in the formation of
unstable nesquehonite (MgCO3·3H2O) and maintained its polymorph during
the carbonation of MgO. Additionally, the carbonated composites produced
with amino acids had a higher carbonation degree and higher stability,
compared to the base batch without amino acids. The presence of amino acid
resulted in the formation of denser carbonation products with a different
morphology than those in the control mix, leading to significantly enhanced carbonation and compressive strength.
Chapter 5 (third aspect) investigated the influence of carbonates (limestone,
magnesite, various hydrated magnesium carbonates (HMCs), and labproduced
HMCs) and non-carbonate (quartz) on the performance of Portland
metakaolin cement binder. The mixtures exhibited a distinct difference in
strength at early ages (i.e. from 3 to 7 days), while at the late ages (after 28
days) compressive strengths were comparable call the binders. Also, the
microstructure of the mixtures was densified by the lab-produced HMCs. The
synergistic reaction between metakaolin and high-reactivity carbonate
produced carboaluminates, which may explain the observed increase in
strength. Moreover, the observed increase in strength cannot solely be
attributed to the carboaluminates; other hydration products may also play a
role. strätlingite and C-A-S-H gel) also play an important role.
Based on the findings from the last two chapters, which approved the
feasibility of magnesia-based materials in the alumina/silicate hydrate binders,
Chapter 6 investigated the practical applications for magnesia in
alumina/silicate hydrate binder systems. The study introduced reactive
magnesia (i.e. MgO) and sodium carbonate, together with an early-age oven
curing regime, as an approach to clay solidification. The results indicated that
incorporating MgO effectively solidified the clay by providing additional Mg2+
and OH- ions. The morphology of hydration phases plays a more important
role than their contents and porosity in strength development.Another
investigation conducted in this thesis is to replace microsilica with waste glass
for preparing MgO-SiO2 formulations to form magnesium silicate hydrate (MS-
H). The results suggested that waste glass can partially replace microsilica
(i.e. up to 50 wt.% replacement level) in MgO-SiO2 formulations without
sacrificing the compressive strength, whereas the complete replacement with
waste glass did not reveal favourable outcomes in terms of performance. The
reactivity and solubility of the silica source played a key role in the formation
of M-S-H, which contributed to the strength development in samples
containing microsilica. This study is original as it was the first in the literature to introduce amino
acids into reactive magnesia mixes to control the polymorphs of HMCs in
carbonated magnesia composites to develop low carbon MgO-clay binder
systems via the use of the polymorphs controlled HMCs. The findings have
suggested the high potential of reactive magnesia-based formulations to be
used in various building applications based on their ability to gain strength via
the sequestration of CO2 and their lower sensitivity to impurities, enabling the
utilization of large quantities of industrial waste.Zhongyuan University of Technolog
The role of diet in cancer: the potential of shaping public policy and clinical outcomes in the UK
Get PDFData availability: No datasets were generated or analysed during the current study.Cancer universally represents one of the largest public health concerns, substantially contributing to global disease burden and mortality. The multifaceted interplay of environmental and genetic factors in the disease aetiology and progression has required comprehensive research to elucidate modifiable elements which can reduce the risk of incidence and improve prognosis. Among these factors, diet and nutrition have emerged as the most fundamental with a significant potential for influence and effect. Nutrition is not only an essential part of human survival, but also a vital determinant of overall health. Certain dietary requirements are necessary to support normal physiology. This includes individualised levels of macronutrients (proteins, carbohydrates and fats) and specific micronutrients (vitamins and minerals). Extensive research has demonstrated that diet plays a role in cancer pathogenesis at the genetic, epigenetic and cellular level. Therefore, its potential as a modifiable determinant of cancer pathogenesis for the purpose of prevention and improving management of disease must be further explored and implemented. The ability to influence cancer incidence and outcomes through dietary changes is underutilised in clinical practice and insufficiently recognised among the general public, healthcare professionals and policy-makers. Dietary changes offer the opportunity for autonomy and control over individuals health outcomes. Research has revealed that particular dietary components, as well as cultural behaviours and epidemiological patterns may act as causative or protective factors in cancer development. This review aims to comprehensively synthesise this research to further explore how to best utilise this knowledge within the community and clinical environment for more effective cancer prevention and therapeutic strategies. The identified key areas for improvement include the development of more specific, widely accepted guidelines, promoting increased involvement of dieticians within cancer multidisciplinary teams, enhancing nutritional education for healthcare professionals and exploring the potential implementation of personalised nutrition tools. A greater understanding of the complex interactions between diet and cancer will facilitate informed clinical interventions and public health policies to reduce global cancer burden and improve care for cancer patients and survivors
Innate immune surveillance in coronavirus disease-2019 (COVID-19)
Get PDFThis thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonSevere SARS-CoV-2 infection is characterised by an unbalanced immune response, excessive inflammation, and respiratory distress syndrome, often leading to multiorgan failure death. This study examines the roles number of innate immune membrane-bound and soluble proteins in SARS-CoV-2 infection, including lung surfactant protein D (SP-D), dendritic cell-specific intercellular adhesion molecule-3 grabbing non-integrin (DC-SIGN), complement component 1 q (C1q), C4b-binding protein (C4BP), factor H (FH), and properdin (Factor P/FP). We hypothesised that SP-D, C1q, C4BP, FH, and FP can play protective roles in the immune surveillance against SARS-CoV-2 infection, where hyperinflammation contributes to the disease severity. SP-D and DC-SIGN are C-type lectin receptors involved in pathogen recognition. SP-D clears pulmonary pathogens, while DC-SIGN involves plays role in many viral infections. Both interact with SARS-CoV-2. The study investigates the possible role of recombinant fragment human SP-D (rfhSP-D) in the interaction between DS-SIGN and SARS-CoV-2. We found that rfhSP-D binds to the SARS-CoV-2 Spike protein, enhancing viral binding and uptake in DC-SIGN -expressing cells. Additionally, rfhSP-D reduces pro-inflammatory cytokines in macrophage-like cells. The roles of C1q and C4BP in SARS-CoV-2 infection were also explored. Both proteins directly bind to the SARS-CoV-2 Spike protein, reducing viral attachment and entry into A549 cells expressing human ACE2 and TMPRSS2. Treatment with C1q and C4BP led to the downregulation of pro-inflammatory cytokines, suggesting their potential in mitigating the inflammatory response. Furthermore, the study assessed the impact of FH and FP on SARS-CoV-2 infection. FH inhibited viral binding and cell entry, attenuating the infection-associated inflammatory response. Conversely, FP promoted viral cell entry, binding, and immune response, potentially influencing infection severity. In conclusion, the study highlights the intricate interplay of innate immune proteins in SARS-CoV- 2 infection. The findings suggest differential modulatory effects of rfhSP-D, C1q, C4BP, FH, and FP in SARS-CoV-2 infections and offer promising therapeutic interventions targeting these factors. Further in vivo research is required to understand the underlying mechanisms and explore their potential clinical applications
A mathematical model for wind-generated particle-fluid flow fields with an application to the helicopter cloud problem
Get PDFData availability statement:
The authors confirm that the data supporting the findings of this study are available within the paper.MSC codes 76-10, 76T99, 76M20, 76M45.We develop a model for the interaction of a fluid flowing above an otherwise static particle bed, with generally the particles being entrained or detrained into the fluid from the upper surface of the particle bed, and thereby forming a fully two phase fluidized cloud above the particle bed. The flow in this large-scale fluidized region is treated as a two-phase flow, whilst the key processes of entrainment and detrainment from the particle bed are treated by examining the local dynamical force balances on the particles in a thin transition layer at the interface between the fully fluidized region and the static particle bed. This detailed consideration leads to the formation of an additional macroscopic boundary condition at this interface, which closes the two-phase flow problem in the bulk fluidized region above. We then introduce an elementary model of the well-known helicopter brownout problem, and use the theory developed in the first part of the paper to fully analyse this model, both analytically and numerically.This research received no specific grant from any funding agency, commercial or not-for-profit sectors
Combined search for electroweak production of winos, binos, higgsinos, and sleptons in proton-proton collisions at √ = 13 TeV
No full textA combination of the results of several searches for the electroweak production of the supersymmetric partners of standard model bosons, and of charged leptons, is presented. All searches use proton-proton collision data at √=13 TeV recorded with the CMS detector at the LHC in 2016–2018. The analyzed data correspond to an integrated luminosity of up to 137 fb−1. The results are interpreted in terms of simplified models of supersymmetry. Two new interpretations are added with this combination: a model spectrum with the bino as the lightest supersymmetric particle together with mass-degenerate Higgsinos decaying to the bino and a standard model boson, and the compressed-spectrum region of a previously studied model of slepton pair production. Improved analysis techniques are employed to optimize sensitivity for the compressed spectra in the wino and slepton pair production models. The results are consistent with expectations from the standard model. The combination provides a more comprehensive coverage of the model parameter space than the individual searches, extending the exclusion by up to 125 GeV, and also targets some of the intermediate gaps in the mass coverage.SCOAP
Innocent Bystanders or the Forgotten Actors? The Role of Parties and Candidates in Building Electoral Campaign Momentum
Get PDFSupplementary Material is available online at: https://journals.sagepub.com/doi/10.1177/00323217241274893#supplementary-materials . For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.Do party or candidate campaigns boost momentum? Momentum in election campaigns is significant because it indicates a greater perception of the likelihood that a party or candidate will perform well, and also because that brings with it an improvement in credibility as a viable contender. Existing explanations of changes in the perception of popularity of candidates and parties over an election campaign relate largely to the impact of media coverage and opinion polls. What is frequently absent is any discussion of the impact of party and candidate campaigns. This is a curious omission since it effectively ignores the central actors in electoral contests – the parties and the candidates. This article seeks to address this lacuna by assessing whether campaign efforts deliver electoral momentum. Using data from three British general elections, we find strong evidence to indicate that campaign efforts at the constituency-level play a key role in delivering momentum.Economic & Social Research Council (ES/M007251/1; ES/R005052/1; ES/T015187/1)
Set-Membership State Estimation for Multirate Nonlinear Complex Networks Under FlexRay Protocols: A Neural-Network-Based Approach
Get PDFIn this article, the set-membership state estimation problem is investigated for a class of nonlinear complex networks under the FlexRay protocols (FRPs). In order to address practical engineering requirements, the multirate sampling is taken into account which allows for different sampling periods of the system state and the measurement. On the other hand, the FRP is deployed in the communication network from sensors to estimators in order to alleviate the communication burden. The underlying nonlinearity studied in this article is of a general nature, and an approach based on neural networks is employed to handle the nonlinearity. By utilizing the convex optimization technique, sufficient conditions are established in order to restrain the estimation errors within certain ellipsoidal constraints. Then, the estimator gains and the tuning scalars of the neural network are derived by solving several optimization problems. Finally, a practical simulation is conducted to verify the validity of the developed set-membership estimation scheme.10.13039/501100001809-National Natural Science Foundation of China (Grant Number: 61933007, U21A2019, 62103095, 62273005 and U22A2044);
Hainan Province Science and Technology Special Fund of China (Grant Number: ZDYF2022SHFZ105);
10.13039/501100005046-Natural Science Foundation of Heilongjiang Province (Grant Number: LH2021F005);
Anhui Polytechnic University (AHPU) High-End Equipment Intelligent Control Innovation Team of China (Grant Number: 2021CXTD005);
Royal Society of the U (Grant Number: 0000DONOTUSETHIS0000.K);
Alexander von Humboldt Foundation of Germany
House Price Dynamics and Mortgage Defaults: Theoretical and Empirical Analysis of the Role of Recourse
Get PDFThis paper examines the dynamics of house prices and mortgage defaults in recourse and non
recourse U.S. metropolitan areas. Within an overlapping generations model, we demonstrate
that house price shocks result in higher default rates in non-recourse markets. While both
markets exhibit negative house price reaction to mortgage defaults, the response is stronger in
non-recourse markets. Our findings highlight the critical role of recourse in determining
mortgage default and house price risk
Visibility through clutter: How could small businesses cut through advertising clutter on Instagram?
Get PDFThis thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonSmall businesses heavily relay on Instagram in order to build their brand with respect to its user friendliness, low cost, and accessibility. However, in a very competitive market it is difficult to capture online attention and develop word of mouth. Instagram can be a powerful marketing tool if properly understood, hence deeper investigation on this platform is required. While current literature has intensively explored the field of social media marketing post launching a business, it is somewhat limited in the pre-launch state. In parallel with the literature scarcity on pre-launch marketing, the motivation behind this research stems from the challenges small businesses encounter within launching. Advertising clutter presents itself as the preeminent challenge as it limits exposure for small businesses. Furthermore, consumers are irritated by the clutter hence it is necessary to empirically validate an approach that assists business in capturing consumer attention in cluttered advertising environments such as Instagram.
This study sheds light on the Food & Beverage sector in the Middle East which is currently among the most popular sectors advertised on Instagram (Crowd Analyzer, 2022). The contribution to the current stream of marketing literature comes from introducing solutions to advertising clutter on Instagram by incorporating Schema Incongruity Theory and providing cues that are viable for hedonic sectors. Furthermore, this research demonstrates the significance of activating bottom-up attention processing for consumers scrolling in cluttered environments such as Instagram. Lastly this research empirically validates a Pre-Launch marketing communication campaign model for new businesses, starting from capturing attention leading to purchase intention.
What can small businesses in the food industry do in order to build an attractive pre-launch marketing campaign? To answer this question, this study employed a three stage mixed methods design for the methodology, where the first qualitative stage consists of 5 focus group semi-structured interviews with middle eastern Instagram users to ask about their experience with restaurant ads and what would capture their attention whilst scrolling through their feed. This stage assisted in validating the pre-launch marketing framework and introduce new ideas that required further investigation. Secondly, upon the findings of the interviews, an experiment design was necessary to provide empirical validation on what type of ads capture consumer attention in cluttered Instagram environments. The experiment was conducted on 62 participants following a within subject design to experiment how consumers react ironic ads compared to traditional. Lastly, to test the rest of the constructs in the framework, a questionnaire was conducted with 323 Instagram users that have a liking for food.
The findings of this study shed light on the necessary tools needed to build a successful pre-launch marketing campaign for small businesses by providing a step by step approach on the type of ads and type of opinion leaders that are most effective in middle eastern food & beverage sector. The findings also indicate the stages that an Instagram user undergoes until reaching the purchase stage. Understanding the stages of the purchase process can help new businesses align their marketing strategy with those stages to assist in building a more effective campaign. This study provides solutions for numerous managerial problems (Lack of marketing plans, a poor comprehension of the industry they operate in, and competition against well established companies) all three are pitfalls for small businesses in the middle east (Albalushi & Naqshbandi, 2022)
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