Brunel University London
  • Uxbridge, Middlesex, United Kingdom
Recent publications
Thin-walled micro parts are widely used in many fields, such as aviation, aerospace, precision engineering, and even micro-molds. Compared with other micro-fabrication technology, micro-milling can be considered as one of the most efficient 3D fabrication techniques. However, due to the vulnerable stiffness of thin-walled micro parts and micro tools, regenerative chatter is prone to occur during the micro-milling process. Severe chatter can lead to large fluctuations in cutting forces, resulting in deterioration of surface roughness/integrity and decreasing in tool life. Therefore, an in-process chatter detection strategy based on the feature extraction of micro-milling forces is proposed in this paper. Micro-milling force signals are measured and processed by advanced algorithms developed. After variational mode decomposition (VMD) for each group of cutting forces, the optimal intrinsic mode function (IMF) is adopted based on the Laplacian score (LS). The multi-scale permutation entropy (MSPE) values of the optimal IMF of each group are calculated, wherein the scale factor s, the embedding dimension m, and the delay time t are obtained by the genetic algorithm (GA). The obtained MSPE values are used as input vectors to train the support vector machine (SVM) classifier, which is used to monitor the stability states of the micro-milling processes. The effectiveness of the proposed strategy is compared with the other classic chatter detection methods and indicators in the micro-milling experiments of thin-walled parts. The results show that the method resulted from the strategy can extract cutting force features effectively and in-process detect chatters accurately in micro-milling thin-walled parts processes.
Employees’ creativity in the education sector has never been more important than the past two years when the global coronavirus disease 2019 (COVID-19) pandemic swept the world. This paper presents a study on employees’ creativity in primary public schools in the Kingdom of Bahrain. The study sheds the light on the role of extrinsic rewards in enhancing employees’ creativity. The findings suggest that extrinsic rewards hinder employees’ creativity for employees’ who are mastery goal-oriented and for employees who have an internal locus and external locus of control. Furthermore, this research finds that the mediating effect of intrinsic motivation and the moderating effect of performance orientation are both insignificant. This study provides clear conditions leading to employees’ creativity; hence it provides multiple theoretical and practical implications that worth consideration.
The chemical pollution crisis severely threatens human and environmental health globally. To tackle this challenge the establishment of an overarching international science–policy body has recently been suggested. We strongly support this initiative based on the awareness that humanity has already likely left the safe operating space within planetary boundaries for novel entities including chemical pollution. Immediate action is essential and needs to be informed by sound scientific knowledge and data compiled and critically evaluated by an overarching science–policy interface body. Major challenges for such a body are (i) to foster global knowledge production on exposure, impacts and governance going beyond data-rich regions (e.g., Europe and North America), (ii) to cover the entirety of hazardous chemicals, mixtures and wastes, (iii) to follow a one-health perspective considering the risks posed by chemicals and waste on ecosystem and human health, and (iv) to strive for solution-oriented assessments based on systems thinking. Based on multiple evidence on urgent action on a global scale, we call scientists and practitioners to mobilize their scientific networks and to intensify science–policy interaction with national governments to support the negotiations on the establishment of an intergovernmental body based on scientific knowledge explaining the anticipated benefit for human and environmental health.
Bacterial vaginosis (BV) is a recurrent dysbiosis that is frequently associated with preterm birth, increased risk for acquisition of human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs). The overgrowth of a key pathobiont, Gardnerella vaginalis , as a recalcitrant biofilm is central to the development of this dysbiosis. Overgrowth of vaginal biofilms, seeded by initial G. vaginalis colonization, leads to recurrent symptomatic BV which is poorly resolved by classically used antibiotics. In this light, the use of bacteriophages and/or their proteins, represents a promising alternative. Here we identify 84 diverse anti- Gardnerella endolysins across 7 protein families. A subset of 36 endolysin candidates were refactored and overexpressed in an E. coli BL21 (DE3) system and 5 biochemically and structurally diverse endolysins were fully characterized. Each candidate endolysin showed good lytic activity against planktonic G. vaginalis ATCC14018, as well as G. vaginalis clinical isolates. These endolysin candidates were assayed in biofilm prevention and disruption assays, with biofilm disruption at low microgram concentrations (5 μg/ml) observed. In addition to clonal G. vaginalis biofilms, endolysin candidates could also successfully disrupt polyspecies biofilms. Importantly, none of our candidates showed lytic activity against commensal lactobacilli present in the vaginal microbiota such as L. crispatus, L. jensenii , L. gasseri , and L. iners or against Atopobium vaginae (currently classified as Fannyhessa vaginae ). The potency and selectivity of these novel endolysins constitute a promising alternative treatment to combat BV, avoiding problems associated with antibiotic resistance, while retaining beneficial commensal bacteria in the vaginal flora. The diverse library of candidates reported here represents a strong repository of endolysins for further preclinical development.
WHO promotes the use of research in policy-making to drive improvements in health, including in achieving Sustainable Development Goals such as tobacco control. The European Union’s new €95 billion Horizon Europe research framework programme parallels these aims, and also includes commitments to fund economic evaluations. However, researchers often express frustration at the perceived lack of attention to scientific evidence during policy-making. For example, some researchers claim that evidence regarding the return on investment from optimal implementation of evidence-based policies is frequently overlooked. An increasingly large body of literature acknowledges inevitable barriers to research use, but also analyses facilitators encouraging such use. This opinion piece describes how some research is integrated into policy-making. It highlights two recent reviews. One examines impact assessments of 36 multi-project research programmes and identifies three characteristics of projects more likely to influence policy-making. These include a focus on healthcare system needs, engagement of stakeholders, and research conducted for organizations supported by structures to receive and use evidence. The second review suggests that such characteristics are likely to occur as part of a comprehensive national health research system strategy, especially one integrated into the healthcare system. We also describe two policy-informing economic evaluations conducted in Spain. These examined the most cost-effective package of evidence-based tobacco control interventions and the cost-effectiveness of different strategies to increase screening coverage for cervical cancer. Both projects focused on issues of healthcare concern and involved considerable stakeholder engagement. The Spanish examples reinforce some lessons from the global literature and, therefore, could help demonstrate to authorities in Spain the value of developing comprehensive health research systems, possibly following the interfaces and receptor model. The aim of this would be to integrate needs assessment and stakeholder engagement with structures spanning the research and health systems. In such structures, economic evaluation evidence could be collated, analysed by experts in relation to healthcare needs, and fed into both policy-making as appropriate, and future research calls. The increasingly large local and global evidence base on research utilization could inform detailed implementation of this approach once accepted as politically desirable. Given the COVID-19 pandemic, increasing the cost-effectiveness of healthcare systems and return on investment of public health interventions becomes even more important.
As a result of the COVID-19 pandemic, face coverings were introduced as a safety measure in certain environments in England and some research suggests that they can affect emotion recognition. Factors such as own-ethnicity bias (e.g. whether people perceiving and expressing emotions are of the same ethnicity) and social biases are also known to influence emotion recognition. However, it is unclear whether these factors interact with face coverings to affect emotion recognition. Therefore, this study examined the effects of face coverings, own-ethnicity biases, and attitudes on emotion recognition accuracy. In this study, 131 participants viewed masked and unmasked emotional faces varying in ethnicity and completed a questionnaire on their attitudes towards face masks. We found that emotion recognition was associated with masks and attitudes: accuracy was lower in masked than unmasked conditions and attitudes towards masks Inside and Outside were associated with emotion recognition. However, a match between perceiver and stimulus ethnicity did not have a significant effect on emotion recognition. Ultimately, our results suggest that masks, and negative attitudes towards them, were associated with poorer emotion recognition. Future research should explore different mask-wearing behaviours and possible in-group/out-group biases and their interaction with other social cues (e.g. in-group biases).
The increasing penetration of Renewable Energy Sources (RES) in distribution networks has led traditional voltage regulation to their boundaries. In order to develop advanced techniques for voltage control in this new context, an adequate and real-time coordination and communication between Transmission System Operators (TSOs) and Distribution System Operators (DSOs) is needed. In this paper, a decentralized TSO-DSO coordination approach for scheduling and deploying optimal reactive power exchanges in the DSO's boundary for improved voltage control in the TSO's networks is proposed. The proposed approach is implemented via a standardized Business Use Case (BUC). The interoperability between the TSO, the DSO, and other stakeholders is solved by designing and developing the BUC within the framework of the International Electrotechnical Commission (IEC) Common Information Model (CIM) family of standards IEC61970, IEC61968, and IEC62325. In view of the lack of pilot tests in the field, the proposed standardized BUC is demonstrated on real-world Slovenian TSO's and DSO's networks. The simulation experiments presented in this paper are twofold. On one hand, the proposed data exchange mechanism based on the standardized BUC demonstrates the feasibility of successfully exchanging data between the TSO, the DSO, and other stakeholders, such as the Significant Grid Users (SGUs) and Meter Operators, as a CIM Common Grid Model Exchange Standard (CGMES) format. On the other hand, the capability of the proposed decentralized TSO-DSO coordination approach to regulate the High Voltage (HV) by managing the reactive power injected by different RES, such as capacitor banks and different Distributed Generators (DGs), viz. hydropower, Photovoltaic (PV), and thermal (co-generation) units, is validated via sensitivity and robustness analyses for different network topologies, DGs’ operating scenarios, and capacitor banks’ sizes and locations. The simulation results show that the proposed approach can manage DGs toward contributing additional (positive or negative) reactive power to reduce the voltage deviations in the grid, improve the power quality at the DSO's boundary by reducing the flow of reactive power from the TSO's to the DSO's networks and vice versa, and keep the HV voltage within safe values. Unfortunately, this is not the case for the capacitor banks, where the capability of the proposed approach to manage their injected reactive power to regulate the HV voltage is highly dependent on their sizes and location, being necessary to be studied on a case-by-case basis.
Code review plays an important role in software quality control. A typical review process involves a careful check of a piece of code in an attempt to detect and locate defects and other quality issues/violations. One type of issue that may impact the quality of software is code smells-i.e., bad coding practices that may lead to defects or maintenance issues. Yet, little is known about the extent to which code smells are identified during modern code review. To investigate the concept behind code smells identified in modern code review and what actions reviewers suggest and developers take in response to the identified smells, we conducted an empirical study of code smells in code reviews by analyzing reviews from four large open source projects from the OpenStack (Nova and Neutron) and Qt (Qt Base and Qt Creator) communities. We manually checked a total of 25,415 code review comments obtained by keywords search and random selection; this resulted in the identification of 1,539 smell-related reviews which then allowed the study of the causes of code smells, actions taken against identified smells, time taken to fix identified smells, and reasons why developers ignored fixing identified smells. Our analysis found that 1) code smells were not commonly identified in code reviews , 2) smells were usually caused by violation of coding conventions, 3) reviewers usually provided constructive feedback, including fixing (refactoring) recommen-2 Xiaofeng Han et al. dations to help developers remove smells, 4) developers generally followed those recommendations and actioned the changes, 5) once identified by reviewers, it usually takes developers less than one week to fix the smells, and 6) the main reason why developers chose to ignore the identified smells is that it is not worth fixing the smell. Our results suggest the following: 1) developers should closely follow coding conventions in their projects to avoid introducing code smells, 2) review-based detection of code smells is perceived to be a trustworthy approach by developers, mainly because reviews are context-sensitive (as reviewers are more aware of the context of the code given that they are part of the project's development team), and 3) program context needs to be fully considered in order to make a decision of whether to fix the identified code smell immediately.
Context Tangled commits are changes to software that address multiple concerns at once. For researchers interested in bugs, tangled commits mean that they actually study not only bugs, but also other concerns irrelevant for the study of bugs. Objective We want to improve our understanding of the prevalence of tangling and the types of changes that are tangled within bug fixing commits. Methods We use a crowd sourcing approach for manual labeling to validate which changes contribute to bug fixes for each line in bug fixing commits. Each line is labeled by four participants. If at least three participants agree on the same label, we have consensus. Results We estimate that between 17% and 32% of all changes in bug fixing commits modify the source code to fix the underlying problem. However, when we only consider changes to the production code files this ratio increases to 66% to 87%. We find that about 11% of lines are hard to label leading to active disagreements between participants. Due to confirmed tangling and the uncertainty in our data, we estimate that 3% to 47% of data is noisy without manual untangling, depending on the use case. Conclusion Tangled commits have a high prevalence in bug fixes and can lead to a large amount of noise in the data. Prior research indicates that this noise may alter results. As researchers, we should be skeptics and assume that unvalidated data is likely very noisy, until proven otherwise.
The COVID-19 pandemic forced most individuals to work from home. Simultaneously, there has been an uptake of digital platform use for personal purposes. The excessive use of technology for both work and personal activities may cause technostress. Despite the growing interest in technostress, there is a paucity of research on the effects of work and personal technology use in tandem, particularly during a crisis such as the COVID-19 pandemic. Using a sample of 306 employees, this paper addresses this research gap. The findings highlight how both work and personal digital platforms induce technostress during the enforced remote work period, which in turn increases psychological strains such as technology exhaustion and decreases subjective wellbeing. Study results also show that employees with previous remote working experience could better negotiate technostress, whereas those with high resilience experience decreased wellbeing in the presence of technostress-induced technology exhaustion in the enforced remote work context.
SME manufacturers of electrical and electronic equipment seem to have high e-waste levels, which is inhibiting SMEs manufacturers in becoming more sustainable. On the other hand, consumers play a major role in enabling the SMEs manufacturers to achieve their sustainability targets as they are responsible for returning their e-waste back to SMEs. Based on the concepts of social marketing theory, this paper aims to examine the type of information that influences consumers’ intention to immediately return their e-waste back to SME manufacturers. A conceptual framework is developed and tested through a survey questionnaire to 394 Malaysian consumers. The relationship of the proposed types of information and information presentation towards consumers’ immediate return attitude, as well as environmental motivation and environmental knowledge as the moderators in consumers’ segmentation are tested. The findings suggest that specific type of return information and message framing have a positive effect on Immediate Return Intention.
The addition of hydrogen peroxide and steam to a hydrogen-fuelled HCCI engine was investigated at various fuel lean conditions (ϕeff = 0.2–0.6) and compression ratios (15–20) using a 0-dimensional numerical model. The use of hydrogen peroxide as an ignition promoter demonstrated increased IMEP (16%–39%), thermal efficiency (up to 2%), and reduced NOx (50%–76%) when compared to the conventional method of intake charge heating. When hydrogen peroxide was used as an ignition promoter, a 15% addition of steam was sufficient to reduce NOx by 93%–97%, though this reduced IMEP and thermal efficiency slightly. When heat transfer was considered and steam addition was increased from 0%–10%, no increase in intake air heating was able to match the IMEP of 5% hydrogen peroxide addition without an increase in the equivalence ratio (up to 40%). The parametric space of hydrogen peroxide (0%–25%) and steam (0%–40%) addition was explored in view of engine performance metrics, showing the complete range of conditions possible through control of both inputs. A three-order reduction in NOx was possible through steam addition. An optimal balance of performance and emissions occurred at 5%–10% hydrogen peroxide and 10%–15% steam addition. In a study of compression ratio, very little hydrogen peroxide addition (<5%) was required to achieve 98% of the maximum efficiency at higher compression ratios (19–20), though at lower compression ratios (<17) impractical quantities of hydrogen peroxide were required. The 10% steam addition present at these conditions led to extremely low NOx levels for ϕeff of 0.3 and 0.4, though at ϕeff of 0.5 NOx levels would require some after-treatment. Maintaining constant a high or low load across steam additions was possible through reasonable adjustment of hydrogen peroxide addition.
This study focuses on the distinctive Egyptian setting, where firms could use multiple audit mechanism voluntarily or mandatory under certain circumstances. We investigate the effects on audit quality and cost of debt. A sample of 1699 firm-year observations of Egyptian listed firms for the 2009-2019 period is used. Abnormal accruals are employed as proxies of audit quality through abnormal working capital accruals and modified-Jones models. Results suggest that joint audits are not associated with both proxies of audit quality. In contrast, the dual audit is positively associated with abnormal accruals leading to conclude that dual audits are not providing a high level of audit quality. But this result holds only in companies with income decreasing discretionary accruals. These results are in line with litigation and reputational risk fears offering motivations for auditors to favour conservative accounting alternatives (i.e., income decreasing discretionary accruals). This implies that firms opting to employ dual audits have a higher level of earnings conservatism. Our evidence also indicates that the choice of multiple audit mechanisms especially joint audits is related to significant increases in the cost of debt, implying a higher perceived level of risk. Further, dual audits decrease the cost of debt only in companies with high earnings management. This study adds to the literature on whether the preference of income-increasing or income decreasing discretionary accruals is related to multiple audit mechanism and consequently affected the cost of debt. Together, our results support the view that voluntary joint audits are not related to audit quality in Egypt compared to mandatory dual audits, which consequently affect the pricing of debt. Our results have important implications for policymakers, audit firms and investors.
An eco-friendly pre-treatment coupled with surface functionalisation were developed to enhance the quality of wheat straw particles to be used for development of high-performance polylactic acid (PLA) compressed strawboard. Eco-friendly hybrid pre-treatment (i.e., hot water followed by steam, H+S) and surface functionalisation processes employing attapulgite nanoclay (AT) and graphene nanoplatelets (G) were used to obtain an appropriate wheat straw surface quality while increasing its compatibility with the PLA matrix. The successful pre-treatment and surface functionalisation of wheat straw particles was verified through characterisation techniques, including SEM, FTIR, XRD, Raman spectroscopy, and TGA. Tensile strength and water absorption properties of compressed strawboards were examined to investigate the influence of pre-treatment and surface functionalisation of wheat straws. The maximum tensile strengths of 28 MPa and 27 MPa were recorded for 10 H+S-AT and 10 H+S-G samples, respectively, which are considerably higher than the value (i.e., 9.7 MPa) registered for the sample without pre-treatment and surface functionalisation (i.e., 10UN). The lowest water absorption after 24 h of immersion was registered for 10UN-G (i.e., 1.6%), which is 11% and 31% lower than the 10UN and 10 H+S samples, respectively. The effect is attributed to an improved interfacial bond between wheat straw and PLA matrix due to the graphene surface functionalisation, as evidenced by the SEM.
In this work, we show the influence of strain in two different forms (plate and foil) of nickel for hydrogen evolution reaction (HER) in alkaline solution and 3.5% NaCl aqueous solution. The presence of tensile strain in nickel foil lowers the overpotential by about 10 mV to reach a current density of 10 mA cm⁻² and improves the reaction kinetics of HER in alkaline solution. The Tafel slope showed a significant change in the strained nickel (i.e., in Ni foil) which gave a value of 111 mV dec⁻¹ compared to unstrained nickel (Ni plate) which was found to be 151 mV dec⁻¹, thus indicating a change in reaction mechanism. Compared to alkaline solution, the effect of strain becomes less pronounced in NaCl solution which can be attributed to Cl⁻ adsorption on the electrode, thereby reducing its catalytic activity.
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Nana Anokye
  • College of Health and Life Sciences, Department of Life Sciences
Derek Groen
  • Department of Computer Science
Ahmed F. Zobaa
  • Department of Electronic and Computer Engineering
Erdem Karakulak
  • Brunel Centre for Advanced Solidification Technology (BCAST)
Derek Fisher
  • Brunel Institute for Bioengineering
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Professor Julia Buckingham BSc PhD FCGI FRSA
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