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Effects of liquid metal particles on performance of triboelectric nanogenerator with electrospun polyacrylonitrile fiber films
No full textLiquid metal (LM) has been used as flexible electrodes for high performance triboelectric nanogenerators (TENGs), however it is unclear how the LM in tribo-layers would affect the performance of TENGs. Here, we report the investigation on the effects of LM particles incorporated into a tribo-layer on the performance of TENGs. The TENGs consist of a polyacrylonitrile (PAN) electrospinning nanofiber membrane, and a polytetrafluoroethylene (PTFE) thin film. LM particles with different concentrations are incorporated into PAN polymer matrix, and used to make the PAN nanofibers membranes by electrospinning. Result shows that the outputs of TENGs become much larger with the increase in LM content. Specifically, the current density increases by about 40%, and both the charge density and output voltage increase by nearly 70%. The overall output power is approximately 2 times higher for the TENG with 1.5 wt% LM concentration, as compared to those of TENGs with pure PAN tribo-layer. However, the output of PAN/LM-PTFE TENGs deteriorates drastically when the LM mass content is increased to 2.5 wt%, at which the composite contains a high density of LM spheroid and spindle particles, deteriorating the generation of triboelectric charge.
Liquid metal (LM) is feasible to be incorporated into electrospinning polymer (polyacrylonitrile, PAN) nanofibers as nano-particle and achieves the modification of TENG tribo-material layer on this account. Compared with TENG based on pure-PAN film, the TENG with PAN/LM composite membrane demonstrates a higher energy output, which only needs a small amount of LM concentration. The result exhibits that the current density increases by about 40% and the output voltage increase by nearly 70%, which is explained by the charge trapping mechanism. When two tribo-material layers begin to separate, a large negative bias generated by electron transfer from the external circuit will cause some electrons to be injected into the LM oxide layers, and then stored in the interface states. The low-cost approach in this study is also potential to other polymers, thus enriching the diversity of modifying tribo-material layers. In addition, it is also feasible to apply similar polymer composite membranes to the energy harvesting of wearable electronic devices. [Display omitted]
•A simple process has been developed to incorporate liquid metal particles into PAN nanofibers uniformly.•Liquid metal has been used as nanoparticle dopants to improve the TENG performance significantly•The charge trapping at the liquid metal surface oxide plays the key role for the performance improvement of TENGs
The employers’ reach: mentoring undergraduate students to enhance employability
No full textThe increased need for supporting students who lack relevant employability skills has resulted in higher education institutions organizing mentoring schemes that will prepare students for future career opportunities. These schemes aim to address the often cited mismatch between what the higher education (HE) sector is offering and the employers’ expectations of future graduates. In addition, such schemes can also go some way to addressing the differential outcomes in graduate employability experienced by students from ‘non-traditional’ backgrounds (Mountford-Zimdars, A., Sanders, J., Moore, J., Sabri, D., Jones, S., & Higham, L. (2016). What can universities do to support all their students to progress successfully throughout their time at university? Perspectives, policy and practice in higher education, pp. 1–10). A number of authors have linked concepts of social and cultural capital to the benefits mentoring schemes can bring to individuals’ employability. For example, mentoring relationships can help individuals develop a professional identity and networks.This chapter presents a case study of a mentoring scheme that was run over a number of years, where undergraduate students were mentored by industry professionals. In the initial phases of the project, a key issue emerged for the students, which was a lack of confidence that hindered them in interacting with their mentors. Over time, the scheme was redesigned to include supported and facilitated opportunities for students and mentors to engage with each other. This resulted in more productive mentoring relationships forming, and students gaining lasting impact from the process in terms of enhanced professional networks, increased confidence and insight into the ‘real world’ of senior management. During our experience of this project, we have found the concepts of social and cultural capital useful for conceptualizing the benefits of mentoring for enhancing employability, but also for understanding the barriers to engagement with such schemes that some groups of students face
Eccentric triboelectric nanosensor for monitoring mechanical movements
No full textFor mechanical equipment or facilities, abnormal vibration and external impact can sometimes cause fatigue or even failure, which might lead to severe accidents. It's necessary to monitor the movement of important devices during their service and identify these abnormal conditions. In recent years, triboelectric nanogenerators (TENGs) have been widely used for collecting energy in many applications, and many experiments show that it is an effective method for self-powered sensing. In this paper, a mathematical model of a novel self-powered eccentric triboelectric nanosensor (Ec-TENS) has been built which can detect linear acceleration and velocity. Governing equations between output voltage and linear acceleration/velocity have been derived. Based on the theoretical model, a sliding-mode prototype has been designed and fabricated to verify the theoretical models through a series of tests. Experimental results have shown that Ec-TENS could generate output voltage once external acceleration exceeds a threshold, and amplitude of voltage could vary with velocity. The output voltage and linear velocity satisfy a specific function, and have a good repeatability and stability. Because of its self-powered feature, the novel Ec-TENS has potentially wide applications in the fields of structural health monitoring (SHM), wearable devices, security systems and aeronautic fields, especially in extreme environmental or unattended conditions.
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•Proposed a novel design of a self-powered eccentric triboelectric nanosensor.•Proposed a theoretical model, governing equations and verified them by tests.•It can detect linear velocity and acceleration change without a power supply
Flammability and thermal stability of unsaturated polyester resin based blends and composites
No full textUnsaturated polyester resin (UP), cured (crosslinked) with styrene, is probably the most widely used thermosetting resin in composites for marine, rail and construction sectors. However, a major drawback of cured UP is that it is highly flammable, largely owing to the copious amounts of flammable styrene evolved in a relatively low temperature depolymerization process, that burn with the production of a dense smoke. The chemical modification of the base resin or the crosslinker with halogenated elements, is the most common and effective method of rendering UP resin flame retardant. An alternative method of fire retarding is to blend UP with micro/nano particulate flame retardants (FR) or additional inherently flame retardant/char forming resins. This chapter discusses the effect of the FR blending component on the curing and morphology of the resin. The thermal stabilities and fire performances of the blends are also discussed
Advanced textiles for wound care
No full textAdvanced Textiles for Wound Care, Second Edition, provides a detailed review of how textiles are incorporated into wound care applications, also explaining the importance and suitability of using textiles on different wound types. It is an interdisciplinary book which directly links textile technology with advances in wound care. The book discusses new developments and techniques related to antimicrobial dressings, the use of biopolymers in infection control management, advanced dressings for managing cavity and cancerous wounds, and the application of nanofibers and novel textile structures in scaffolds, among other new areas. This updated edition also reflects recent changes in regulatory affairs.The book is essential reading for manufacturers, designers, scientists and producers of wound care materials. It is a valuable resource for professionals within the medical sector, as well as those in academia, enabling materials scientists and engineers in both academia, and at medical device companies, to stay abreast of new technology
Using learning technology to embed professionalism : a team approach
No full textProfessionalism is an essential attribute, which is fundamental to personal development, self-awareness and preparation for future employment across all disciplines. We often expect our learners to have the essential knowledge and understanding of professional attitudes and behaviours at the start of their programme of study. However, it is widely recognised that due to societal and cultural change, social media, and many other factors, the term `Professionalism` does not always share the same meaning. In order to develop a greater awareness and promote individual development of learners, our aim is to prepare them for professional practice and regulation through professional bodies. Our overall strategic agenda is to bring professionalism to the forefront of education, and embed it with our programmes of study.This presentation will discuss how the School of Nursing and Midwifery has worked with the Academic Librarian for the School to develop a section in LEAP Online about Professionalism.We will discuss how we collaborated to design the content explaining professionalism and its importance, developed scenario based activities for the students to measure their understanding of professionalism and finally test their knowledge and understanding by gaining a digital badge.We will reflect on how our experience as practitioners has helped shape this exciting new content and our plans to develop it further and embed across all subject areas within the university
Assessment of Upstream Human Intervention Coupled with Climate Change Impact for a Transboundary River Flow Regime: Nile River Basin
No full textThe aim of this article is to determine how human interventions in upstream countries coupled with drought events are affecting the flow regime of downstream countries using the Nile River basin for illustrative purposes. This has been addressed by assessing climate change in the study area through analyses of precipitation data obtained from the Global Precipitation Climatology Centre (GPCC) and detecting if there is a trend, and subsequently calculating drought events in the main basins impacting on the downstream flow. Then river discharge data were analysed using different hydraulic indices at key stations in the downstream country and measuring the alterations occurring in the flow. The degree of alteration is a function of the number of civil engineering projects being in operation and classified by time windows; pre-alteration is between 1900 and 1925, while the alteration period is between 1933 and 2012. The alteration period was classified into three periods based on the degree of alteration. The findings revealed that there are changes in the river flow regime caused by both changes in the rainfall pattern in addition to the regulation in the upstream countries. There is a direct relationship between the interventions in the upstream countries and changes in the flow regime especially when coupled with drought events. By increasing the water usage upstream, there is an increase in the alteration of the flow downstream. The years between 2000 and 2012 were linked to the highest alterations between the modified years
Senses Without Names: Affective Becomings in William Faulkner and Carson McCullers
No full textThis chapter argues that Nietzsche’s philosophy is of central importance to affect theory, particularly in the field of literary criticism. Marsden explores the idea that literary texts generate new and strange affective forces but that these are frequently commuted to normative models of human experience when analyzed by literary critics. Inflecting Brian Massumi’s influential work on affect theory with a Nietzschean critique of value, Marsden offers a reading of William Faulkner’s The Sound and the Fury and Carson McCullers’ The Member of the Wedding, which remains alert to the power of affective becoming to communicate “senses without names.