10,898 research outputs found
Recent developments in 2D materials for energy harvesting applications
The ever-increasing demand for energy as a result of the growing interest in applications, such as the Internet of Things and wearable systems, etc, calls for the development of self-sustained energy harvesting solutions. In this regard, 2D materials have sparked enormous interest recently, due to their outstanding properties, such as ultra-thin geometry, high electromechanical coupling, large surface area to volume ratio, tunable band gap, transparency and flexibility. This has given rise to noteworthy advancements in energy harvesters such as triboelectric nanogenerators (TENGs), piezoelectric nanogenerators (PENGs) and photovoltaics based on 2D materials. This review introduces the properties of different 2D materials including graphene, transition metal dichalcogenides, MXenes, black phosphorus, hexagonal boron nitride, metal-organic frameworks and covalent-organic frameworks. A detailed discussion of recent developments in 2D materials-based PENG, TENG and photovoltaic devices is included. The review also considers the performance enhancement mechanism and importance of 2D materials in energy harvesting. Finally, the challenges and future perspectives are laid out to present future research directions for the further development and extension of 2D materials-based energy harvesters
Recommended from our members
The impact of employees' working relations in creating and retaining trust: the case of the Bahrain Olympic Committee
Introduction: This thesis investigates the impact of employees’ working relations in creating, maintaining and retaining trust in the Bahrain Olympic Committee (BOC).
Aim: The main aim of this thesis is to determine how the three groups of Organisational Trust variables, namely Social System Elements (SSE), Factors of Trustworthiness (FoT) and Third-Party Gossip (TPG), affect employees’ Organisational Trust (OTR) in the BOC and promote Organisational Citizenship Behaviour (OCB). To answer this main aim, a conceptual framework was created that focused on exploring the following research aims: (1) the interrelationship between SSE and FoT, (2) the effect of SSE on OTR, (3) the impact of TPG on OTR and (4) the effect of OTR on overall OCB.
Methodology: The study uses a mixed-method case study research style that included in-depth semi-structured interviews with 17 managers, an online questionnaire survey with 320 employees of the BOC and an analysis of the BOC’s Annual Reports from 2015 to 2018.
Results: The qualitative and quantitative findings indicate, firstly, that there is a significant interrelationship between SSE and FoT, establishing that SSE’s perception of organisational justice (OJ), including that FoTs benevolence and integrity as the most important factors in yielding employees’ trust in the BOC. Secondly, it has been established that SSEs have significant direct and indirect effects on OTR. Thirdly, negative and positive TPG concurrently occurred in the BOC and the prevalence of negative TPG poses more impact on OTR. Finally, this study’s findings demonstrated OTR’s effect in generating OCB, including that Civic Virtue was rated as the most preferred of the five OCB themes; this indicates the managers’ and the employees’ strong emotional attachment and support of the activities taking place at the BOC.
Contributions: Overall, this thesis substantially contributes to OTR literature, particularly in the context of the Middle East. It also proposes several insightful recommendations for future research and practical implications for practitioners in the field of Organisational Trust
Beam scanning by liquid-crystal biasing in a modified SIW structure
A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium
Multi-Robot Multi-Room Exploration with Geometric Cue Extraction and Spherical Decomposition
This work proposes an autonomous multi-robot exploration pipeline that
coordinates the behaviors of robots in an indoor environment composed of
multiple rooms. Contrary to simple frontier-based exploration approaches, we
aim to enable robots to methodically explore and observe an unknown set of
rooms in a structured building, keeping track of which rooms are already
explored and sharing this information among robots to coordinate their
behaviors in a distributed manner. To this end, we propose (1) a geometric cue
extraction method that processes 3D map point cloud data and detects the
locations of potential cues such as doors and rooms, (2) a spherical
decomposition for open spaces used for target assignment. Using these two
components, our pipeline effectively assigns tasks among robots, and enables a
methodical exploration of rooms. We evaluate the performance of our pipeline
using a team of up to 3 aerial robots, and show that our method outperforms the
baseline by 36.6% in simulation and 26.4% in real-world experiments
An empirical investigation of the relationship between integration, dynamic capabilities and performance in supply chains
This research aimed to develop an empirical understanding of the relationships between integration,
dynamic capabilities and performance in the supply chain domain, based on which, two conceptual
frameworks were constructed to advance the field. The core motivation for the research was that, at
the stage of writing the thesis, the combined relationship between the three concepts had not yet
been examined, although their interrelationships have been studied individually.
To achieve this aim, deductive and inductive reasoning logics were utilised to guide the qualitative
study, which was undertaken via multiple case studies to investigate lines of enquiry that would
address the research questions formulated. This is consistent with the author’s philosophical
adoption of the ontology of relativism and the epistemology of constructionism, which was considered
appropriate to address the research questions. Empirical data and evidence were collected, and
various triangulation techniques were employed to ensure their credibility. Some key features of
grounded theory coding techniques were drawn upon for data coding and analysis, generating two
levels of findings. These revealed that whilst integration and dynamic capabilities were crucial in
improving performance, the performance also informed the former. This reflects a cyclical and
iterative approach rather than one purely based on linearity. Adopting a holistic approach towards
the relationship was key in producing complementary strategies that can deliver sustainable supply
chain performance.
The research makes theoretical, methodological and practical contributions to the field of supply
chain management. The theoretical contribution includes the development of two emerging
conceptual frameworks at the micro and macro levels. The former provides greater specificity, as it
allows meta-analytic evaluation of the three concepts and their dimensions, providing a detailed
insight into their correlations. The latter gives a holistic view of their relationships and how they are
connected, reflecting a middle-range theory that bridges theory and practice. The methodological
contribution lies in presenting models that address gaps associated with the inconsistent use of
terminologies in philosophical assumptions, and lack of rigor in deploying case study research
methods. In terms of its practical contribution, this research offers insights that practitioners could
adopt to enhance their performance. They can do so without necessarily having to forgo certain
desired outcomes using targeted integrative strategies and drawing on their dynamic capabilities
ABC: Adaptive, Biomimetic, Configurable Robots for Smart Farms - From Cereal Phenotyping to Soft Fruit Harvesting
Currently, numerous factors, such as demographics, migration patterns, and economics, are leading to the critical labour shortage in low-skilled and physically demanding parts of agriculture. Thus, robotics can be developed for the agricultural sector to address these shortages. This study aims to develop an adaptive, biomimetic, and configurable modular robotics architecture that can be applied to multiple tasks (e.g., phenotyping, cutting, and picking), various crop varieties (e.g., wheat, strawberry, and tomato) and growing conditions. These robotic solutions cover the entire perception–action–decision-making loop targeting the phenotyping of cereals and harvesting fruits in a natural environment.
The primary contributions of this thesis are as follows. a) A high-throughput method for imaging field-grown wheat in three dimensions, along with an accompanying unsupervised measuring method for obtaining individual wheat spike data are presented. The unsupervised method analyses the 3D point cloud of each trial plot, containing hundreds of wheat spikes, and calculates the average size of the wheat spike and total spike volume per plot. Experimental results reveal that the proposed algorithm can effectively identify spikes from wheat crops and individual spikes. b) Unlike cereal, soft fruit is typically harvested by manual selection and picking. To enable robotic harvesting, the initial perception system uses conditional generative adversarial networks to identify ripe fruits using synthetic data. To determine whether the strawberry is surrounded by obstacles, a cluster complexity-based perception system is further developed to classify the harvesting complexity of ripe strawberries. c) Once the harvest-ready fruit is localised using point cloud data generated by a stereo camera, the platform’s action system can coordinate the arm to reach/cut the stem using the passive motion paradigm framework, as inspired by studies on neural control of movement in the brain. Results from field trials for strawberry detection, reaching/cutting the stem of the fruit with a mean error of less than 3 mm, and extension to analysing complex canopy structures/bimanual coordination (searching/picking) are presented.
Although this thesis focuses on strawberry harvesting, ongoing research is heading toward adapting the architecture to other crops. The agricultural food industry remains a labour-intensive sector with a low margin, and cost- and time-efficiency business model. The concepts presented herein can serve as a reference for future agricultural robots that are adaptive, biomimetic, and configurable
Bildung in der digitalen Transformation
Die Coronapandemie und der durch sie erzwungene zeitweise Übergang von Präsenz- zu Distanzlehre haben die Digitalisierung des Bildungswesens enorm vorangetrieben. Noch deutlicher als vorher traten dabei positive wie negative Aspekte dieser Entwicklung zum Vorschein. Während den Hochschulen der Wechsel mit vergleichsweise geringen Reibungsverlusten gelang, offenbarten sich diese an Schulen weitaus deutlicher. Trotz aller Widrigkeiten erscheint eines klar: Die zeitweisen Veränderungen werden Nachwirkungen zeigen. Eine völlige Rückkehr zum Status quo ante ist kaum noch vorstellbar. Zwei Fragen bestimmen vor diesem Hintergrund die Doppelgesichtigkeit des Themas der 29. Jahrestagung der Gesellschaft für Medien in der Wissenschaft (GMW). Erstens: Wie ‚funktioniert‘ Bildung in der sich derzeit ereignenden digitalen Transformation und welche Herausforderungen gibt es? Und zweitens: Befindet sich möglicherweise Bildung selbst in der Transformation? Beiträge zu diesen und weiteren Fragen vereint der vorliegende Tagungsband
Tourism and heritage in the Chornobyl Exclusion Zone
Tourism and Heritage in the Chornobyl Exclusion Zone (CEZ) uses an ethnographic lens to explore the dissonances associated with the commodification of Chornobyl's heritage.
The book considers the role of the guides as experience brokers, focusing on the synergy between tourists and guides in the performance of heritage interpretation. Banaszkiewicz proposes to perceive tour guides as important actors in the bottom-up construction of heritage discourse contributing to more inclusive and participatory approach to heritage management. Demonstrating that the CEZ has been going through a dynamic transformation into a mass tourism attraction, the book offers a critical reflection on heritagisation as a meaning-making process in which the resources of the past are interpreted, negotiated, and recognised as a valuable legacy. Applying the concepts of dissonant heritage to describe the heterogeneous character of the CEZ, the book broadens the interpretative scope of dark tourism which takes on a new dimension in the context of the war in Ukraine.
Tourism and Heritage in the Chornobyl Exclusion Zone argues that post-disaster sites such as Chornobyl can teach us a great deal about the importance of preserving cultural and natural heritage for future generations. The book will be of interest to academics and students who are engaged in the study of heritage, tourism, memory, disasters and Eastern Europe
Recommended from our members
Can I Get a Witness?—Living While Black Death is Trending
It is not uncommon for graphic scenes of violence and death to infiltrate our timelinesfrom retweets, reposts, and shares. I often question how much control do we really have over the images that enter our feed? In what ways are we affected and influenced by these images? How do we relate to these images and video clips that are played and replayed before us? In what ways are these images evoking or are related to past scenes of racist violence? In what ways are these racially violent moments captured in photos and videos and shared online speaking to a Black consciousness?
This project comparatively researches and examines the relationship between past modes and methods of Black trauma curation in the past, to contemporary modes of dissemination on social media in order to argue that contemporary uses of spaces such as Instagram, Facebook, and Twitter serve as an extension of previous scrapbooking methods. By comparing The Emmet Till Generation and their curation of trauma via scrapbooks which were used to galvanize social movements, and impact organizing efforts of the youth, The Trayvon Generation today uses social media in a similar fashion; to bear witness, to organize, and to curate digital memorials for the dead. Witnessing is further extended and complicated on digital platforms, providing an abundance of visual evidence that has proven to be vital in leading tp prosecutions and arrests of violent state officials, and perpetrators of extrajudicial violence.
These live or recorded moments of witnessing are used not only as evidence, but to inform the public. However, we have always known that it’s always happening somewhere, even if we aren’t around to witness it. With that said, what are the effects of having the duty, and the responsibility to bear witness? Paying particular attention to Black youth, this project examines their presence and usage of social media spaces. By analyzing young Black people’s use of social media platforms in relation to Darnella Frazier’s strategic use Facebook, this project examines how Black youth and witnessing is currently driving a cultural shift in entertainment media that highlights witnessing death as a significant milestone for Black youth that marks the transition between childhood and adulthood. It is also impacting entertainment media that is not marketed towards Black people, further highlighting Black witnessing of racialized violence at the intersection of technology as both a contemporary and future issue through its inclusion in contemporary media.Witnessing for Black people is framed as being both necessary and traumatic.
This project concludes with an in depth examination of speculative media to reveal the implications of both the present and the future intersections of race relations, state violence and technology. Through analyses of interviews, image circulation and dissemination, magazine articles, social media platforms, visual and speculative media, this dissertation works to address and attempts to answer the aforementioned questions
- …