20505 research outputs found
Sort by
Preliminary guidelines for the rotorcraft certification by simulation process: update no. 1, March 2023
Get PDFThis document presents preliminary Guidance for the application of (rotorcraft) flight modelling and simulation in support of certification for compliance with standards CS-27 and CS-29, PART B (Flight) and other Flight related aspects (e.g. CS-29, Appendix B, Airworthiness Criteria for Helicopter Instrument Flight).
The Guidance is presented in the form of a structured process, starting from the relevant paragraphs in the Certification Specifications, through a comprehensive description of the assembly of flight simulation requirements, informed by judgements on Influence, Predictability and Credibility, and on into the detailed building of the three major elements of the process:
• the flight simulation model (FSM),
• the flight simulator (FS), and
• the flight test measurement system (FTMS).
The FTMS feeds both the flight model and simulator development with real-world test data to support validation and fidelity assessment. A structured and systematic approach to data/configuration management and documentation is recommended, aided by the creation of the Rotorcraft Certification by Simulation (RCbS) project management plan.
This is the first update of the RCbS Guidelines and includes modifications based on the first round of feedback received before and after the European Rotors RoCS workshop held in Cologne on November 9th 2022. The Guidelines will continue to be updated, as appropriate, with the next major revision to include exercising the process in case studies based on applicable certification requirements from EASA CS-27 and CS-29 (to appear in Section 10). In the current update, the RoCS team have also addressed the issue of resourcing the RCbS process (within Section 9) and suggested potential next steps for aspiring applicants (new Section 11)
Effects of fiber orientation on tool wear evolution and wear mechanism when cutting carbon fiber reinforced plastics
Get PDFThe aim of the present paper is to reveal the influence of different fiber orientations on the tool wear evolution and wear mechanism. Side-milling experiments with large-diameter milling tools are conducted. A finite element (FE) cutting model of carbon fiber reinforced plastics (CFRP) is established to get insight into the cutting stress status at different wear stages. The results show that different fiber orientations bring about distinct differences in the extent, profile and mechanism of tool wear. Severer wear occurs when cutting 45° and 90° plies, followed by 0°, correspondingly, the least wear is obtained when θ = 135° (θ represents the orientation of fibers). Moreover, the worn profiles of cutting tools when θ = 0° and 45° are waterfall edge, while round edge occurs when θ = 135° and a combined shape of waterfall and round edge is obtained when θ = 90°. The wear mechanisms under different fiber orientations are strongly dependent on the cutting stress distributions. The evolution of tool wear profile is basically consistent with the stress distribution on the tool surface at different wear stages, and the extent of tool wear is determined by the magnitude of stress on the tool surface. Besides, the worn edges produce an actual negative clearance angle, which decreases the actual cutting thickness and leads to compressing and bending failure of fibers beneath the cutting region as well as low surface qualities.Chinese Journal of Aeronautic
Wearable and invisible sensor design for eye-motion monitoring based on ferrofluid and electromagnetic sensing technologies
Get PDFFor many human body diseases, treatments in the early stages are more efficient and safer than those in the later stages; therefore, detecting the early symptoms of a disease is crucial. One of the most significant early indicators for diseases is bio-mechanical motion. This paper provides a unique way of monitoring bio-mechanical eye motion based on electromagnetic sensing technology and a ferro-magnetic material, ferrofluid. The proposed monitoring method has the advantages of being inexpensive, non-invasive, sensor-invisible and extremely effective. Most of the medical devices are cumbersome and bulky, which makes them hard to apply for daily monitoring. However, the proposed eye-motion monitoring method is designed based on ferrofluid eye make-up and invisible sensors embedded inside the frame of glasses such that the system is wearable for daily monitoring. In addition, it has no influence on the appearance of the patient, which is beneficial for the mental health of some patients who do not want to attract public attention during treatment. The sensor responses are modelled using finite element simulation models, and wearable sensor systems are created. The designed frame of the glasses is manufactured based on 3-D printing technology. Experiments are conducted to monitor eye bio-mechanical motions, such as the frequency of eye blinking. Both the quick blinking behaviour with an overall frequency of around 1.1 Hz and the slow blinking behaviour with an overall frequency of around 0.4 Hz can be observed through experimentation. Simulations and measurements results show that the proposed sensor design can be employed for bio-mechanical eye-motion monitoring. In addition, the proposed system has the advantages of invisible sensor set-up and will not affect the appearance of the patient, which is not only convenient for the daily life of the patient but also beneficial for mental health.Engineering and Physical Sciences Research Council (EPSRC): EP/T006382/1Bioengineerin
Two world views? How regular and reserve Royal Marines perceive each other
Get PDFEffective integration of the Regular and Reserve Armed Forces is essential to operational effectiveness, but evidence suggests that this remains problematic. Past research has focused on the professional values of Regulars and the perceptions that this group holds about Reservists. In this study, we argue that it is necessary to consider the perceptions of both Regulars and Reservists to truly understand the barriers to integration between these elements of Defence. This study investigates what Regular and Reserve Royal Marines see as the important constructs related to each group, through the use of repertory grid technique with 18 Regulars and 16 Reservists. Not only did the Regulars and Reservists in this study see different constructs as important, they also ascribed different constructs to each group. These differences are potentially problematic when aiming to integrate the Regular and Reserve Armed Forces
Modelling challenges of blockchain technology enabled healthcare sustainable supply chain management: a modified-total interpretive structural modelling approach
Get PDFBlockchain technology (BCT) is beneficial for the Healthcare Sustainable Supply Chain (HSSC), and the adoption of this technology provides many benefits improving the performance of the supply chain, effortless information sharing, mitigation of data modification, etc. On the contrary, this study focuses on the various challenges that come in the path while adopting the BCT. For this, the present study initially identified the multiple challenges from the in-depth literature review. Then, the Delphi method was applied for further analysis and scalability of each challenge. Afterward, Modified-Total Interpretive Structural Modeling (M-TISM) approach is used for identifying the criticality of challenges based on the classification of challenges into different levels. This operation provides the driving and dependence power of each challenge.Furthermore, MICMAC (Cross-Impact Matrix Multiplication Analysis) analysis was performed. At the end of the analysis, the authors found the six critical challenges related to the adoption of BCT in the Healthcare Sustainable Supply Chain (HSSC). These critical challenges are the Economical Challenge (C3), Stakeholder commitment and careful handling of BCT (C2), Combining SSCM practices to BCT(C7), Lack of government intentions to promote BCT in SCM (C6), Data Security threat (C1) and Poor infrastructure for the adoption of BCT (C4). The stakeholders of HSSC should make an effort to control them on a priority basis. In addition to this, the authors also provided the practical implication of the study and future research direction for better adoption of BCT in the Healthcare Sustainable Supply Chain.Operations Management Researc
Parametric analysis of battery-electric rotorcraft configurations to fly on Mars
Get PDFThe success of NASA’s Ingenuity Helicopter promises that the future exploration of Mars will include aerobots in line with rovers and landers. However, Ingenuity lacks long-range endurance and scientific payload capacity because of its small and elementary design. In the series of optimised Martian drone concepts development, we introduced in this paper - an initial sizing of rotary eVTOL design configurations based on the performed parametric analysis for hover and vertical climb using simplified rotorcraft momentum theory, for a set of more challenging requirements for a Martian aerobot mission and sized to fit into the maximum spacecraft aeroshell limit. A tandem rotor configuration was found to be the most efficient configuration, whereas a conventional single main rotor configuration with small diameters manifested the poorest performance.Aerospace Europe Conference Joint 10th EUCASS - 9th CEAS Conference 202
The impact of performance measurement diversity on customer-oriented selling behavior
Get PDFMotivated by recent high-profile cases of salespeople behaving ‘badly’ (i.e., unethically, aggressively, or misleading toward customers), we investigate traditional behavioral controls to examine the specific relationship between performance measurement choices and selling behavior with a survey of 207 business-to-business salespeople. Borrowing from attention-based theory and the theory of planned behavior, our findings suggest that sales management can encourage more pro-customer behavior by using a more diverse performance measurement schema to influence the underlying drivers of customer-oriented selling behavior, including salesperson attitudes and subjective norms. This is particularly important in transactional selling environments where the use of diverse measures has the strongest effect on pro-customer attitudes and customer-oriented selling behavior.Industrial Marketing Managemen
Barriers and enablers to uptake of agroecological and regenerative farming practices, and stakeholder views about ‘living labs’
Get PDFThis report forms the second component of a Defra-sponsored research project entitled “Evaluating the productivity, environmental sustainability and wider impacts of agroecological compared to conventional farming systems”. The first component comprised a rapid evidence review of regenerative/agroecological farming systems. This second component describes and discusses the results of a survey to explore i) farmer and stakeholder definitions of agroecological and regenerative farming, ii) the barriers to the adoption of agroecological and regenerative farming, and iii) farmer and stakeholder views towards the concept of ‘living labs’ as a way to share research and learnings about agroecological/regenerative farming (Figure 1)
Evaluating agroecological farming practices
Get PDFThere are a range of definitions for agroecologically-related farming systems and practices. In brief, organic farming places strong restrictions on inputs, agroecological analyses often focus on principles, and regenerative farming typically emphasises the enhancement of soil health and the diversity of agricultural and wild species at a farm-scale. Perhaps surprisingly the role of agroecological systems in reducing net greenhouse gas emissions from food and farming is implicit rather than explicit. Despite some literature contrasting agroecological and technical approaches, many authors indicate that the desirability of farming practices should be determined by their impact at the appropriate scale. Sustainable intensification has been defined as maintaining or enhancing agricultural production while enhancing or maintaining the delivery of other ecosystem services. Approaches such as the Global Farm Metric and LEAF Marque Certification can support the integrated assessment of 12 groupings of attributes at a farm-scale covering inputs and outputs, and environmental and social impacts. In this report we reviewed the following 16 practices: crop rotations, conservation agriculture, cover crops, organic crop production, integrated pest management, the integration of livestock to crop systems, the integration of crops to livestock systems, field margin practices, pasture-fed livestock systems, multi-paddock grazing, organic livestock systems, tree crops, tree-intercropping, multistrata agroforestry and permaculture, silvopasture, and rewilding
Fostering an “investigating mindset”: Why is it important in digital forensic science education?
Get PDFThe importance of the field of digital forensics (DF) is growing, where digital evidence is increasingly recognized as a crucial part of many investigations. As a result, criminal justice systems rely on DF practitioners to conduct robust investigations of digital devices and their data, and interpret and present these results in a way that can be relied upon. Undertaking this task appropriately requires a practitioner to have a range of skills; however, focus is often placed on the need for and importance of technical competency. Technical skills are vital in this role, that cannot be in dispute; however, this work discusses the need for practitioners to also have an “investigative mindset.”WIREs Forensic Scienc