We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure no-reply@cambridge.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Master the principles of flight dynamics, performance, stability, and control with this comprehensive and self-contained textbook. A strong focus on analytical rigor, balancing theoretical derivations and case studies, equips students with a firm understanding of the links between formulae and results. Over 130 step-by-step examples and 130 end-of-chapter problems cement student understanding, with solutions available to instructors. Computational Matlab code is provided for all examples, enabling students to acquire hands-on understanding, and over 200 ground-up diagrams, from simple “paper plane” models through to real-world examples, draw from leading commercial aircraft. Introducing fundamental principles and advanced concepts within the same conceptual framework, and drawing on the author's over 20 years of teaching in the field, this textbook is ideal for senior undergraduate and graduate-level students across aerospace engineering.
The experimental investigation focuses on the effects of a short splitter plate on the flow physics of a circular cylinder in proximity to a wall by particle image velocimetry. The Reynolds number is Re = 3900, and the near-wall cylinder is immersed in turbulent boundary layer flow. Three gap ratios (i.e. $G/D$ = 0.25, 0.5 and 1) are considered, and the splitter plate length is $L/D=0$, 0.25, 0.5, 0.75 and 1. For $G/D$ = 0.5 and 1, as $L/D$ increases from 0 to 1, the splitter plate facilitates the cylinder shear layers to elongate downstream, and the vortex formation length is increased, which leads to the increase of the range of the recirculation region. For $G/D$ = 0.25, the wall suppression on the wake vortex formation is enhanced, and the variations of the vortex formation length and the range of the recirculation region with $L/D$ are small. The Strouhal number St presents a decrease with increasing $L/D$ for the three gap ratios. The effects of $L/D$ on the vortex evolution are revealed. For $G/D$ = 0.5 and 1, as $L/D$ increases, the induction of the lower wake vortex on the wall secondary vortex becomes weaker due to the reduction in strength of the wake vortex and the increase of the vortex formation length. Additionally, the wake fluctuation intensity is decreased with the increase of $L/D$ due to the splitter plate suppression. For $G/D$ = 0.25, theL/D influences on evolution of the wake vortices and wall secondary vortex are small, which result in weaker variation of the wake fluctuation intensity with $L/D$.
This chapter introduces a selection of methods applicable for identifying and extracting paradata from existing datasets and data documentation which can then be used to complement existing formal documentation of practices and processes. Data reuse, in its multiple forms, enables researchers to build upon the foundations laid by previous studies. Retrospective methods for eliciting paradata, including qualitative and quantitative backtracking and data forensics, provide means to get insights into past research practices and processes for data-driven analysis. The methods discussed in this chapter enhance understanding of data-related practices and processes, reproducibility of findings by facilitating the replication and verification of results through data reuse. Key references and further reading are provided after each method description.
This chapter introduces methods for generating and documenting paradata before and during data creation practices and processes (i.e. prospective and in-situ approaches, respectively). It introduces formal metadata-based paradata documentation using standards and controlled vocabularies to contribute to paradata consistency and interoperability. Narrative descriptions and recordings are advantageous for providing contextual richness and detailed documentation of data generation processes. Logging methods, including log files and blockchain technology, allow for automatic paradata generation and for maintaining the integrity of the record. Data management plans and registered reports are examples of measures to prospectively generate potential paradata on forthcoming activities. Finally, facilitative workflow-based approaches are introduced for step-by-step modelling of practices and processes. Rather than suggesting that a single approach to generating and documenting paradata will suffice, we encourage users to consider a selective combination of approaches, facilitated by adequate institutional resources, technical and subject expertise, to enhance the understanding, transparency, reproducibility and credibility of paradata describing practices and processes.
This study aims to explore the feasibility and accuracy of utilizing large language models (LLMs) to assess the risk of bias (ROB) in cohort studies. We conducted a pilot and feasibility study in 30 cohort studies randomly selected from reference lists of published Cochrane reviews. We developed a structured prompt to guide the ChatGPT-4o, Moonshot-v1-128k, and DeepSeek-V3 to assess the ROB of each cohort twice. We used the ROB results assessed by three evidence-based medicine experts as the gold standard, and then we evaluated the accuracy of LLMs by calculating the correct assessment rate, sensitivity, specificity, and F1 scores for overall and item-specific levels. The consistency of the overall and item-specific assessment results was evaluated using Cohen’s kappa (κ) and prevalence-adjusted bias-adjusted kappa. Efficiency was estimated by the mean assessment time required. This study assessed three LLMs (ChatGPT-4o, Moonshot-v1-128k, and DeepSeek-V3) and revealed distinct performance across eight assessment items. Overall accuracy was comparable (80.8%–83.3%). Moonshot-v1-128k showed superior sensitivity in population selection (0.92 versus ChatGPT-4o’s 0.55, P < 0.001). In terms of F1 scores, Moonshot-v1-128k led in population selection (F = 0.80 versus ChatGPT-4o’s 0.67, P = 0.004). ChatGPT-4o demonstrated the highest consistency (mean κ = 96.5%), with perfect agreement (100%) in outcome confidence. ChatGPT-4o was 97.3% faster per article (32.8 seconds versus 20 minutes manually) and outperformed Moonshot-v1-128k and DeepSeek-V3 by 47–50% in processing speed. The efficient and accurate assessment of ROB in cohort studies by ChatGPT-4o, Moonshot-v1-128k, and DeepSeek-V3 highlights the potential of LLMs to enhance the systematic review process.
Commonly referred to as the ‘father of spaceflight’ and ‘king of rocketry’, Qian Xuesen (1911–2009) is for many Chinese citizens the pre-eminent scientist of the twentieth century. Trained at the California Institute of Technology, he co-founded the Jet Propulsion Laboratory before returning to China in 1955, where he became instrumental in the space programme and the missile industry. This article investigates Qian’s ascent from aeronautical engineer known only within expert circles to China’s face of space. It charts his celebrification, particularly after the Tiananmen Square crackdown, and distinguishes five facets of a rocket star in the making. Transforming Qian into China’s quintessential technocelebrity and transfiguring his persona into the cornerstone of astrocultural production helped propagate spaceflight activities, rendering outer space an imaginable arena for both the state and the public. Yet, as the analysis of a comprehensive body of visual materials, media reports, biographies and obituaries shows, ultimately Qian’s carefully crafted persona is what Ernesto Laclau has termed an ‘empty signifier’. Qian is space, and space Qian, but little else. If historians are to understand the allure and inner workings of the global Space Age, then historicizing the orchestrated rise of non-Western space personas such as Qian Xuesen proves key.
To make sense of data and use it effectively, it is essential to know where it comes from and how it has been processed and used. This is the domain of paradata, an emerging interdisciplinary field with wide applications. As digital data rapidly accumulates in repositories worldwide, this comprehensive introductory book, the first of its kind, shows how to make that data accessible and reusable. In addition to covering basic concepts of paradata, the book supports practice with coverage of methods for generating, documenting, identifying and managing paradata, including formal metadata, narrative descriptions and qualitative and quantitative backtracking. The book also develops a unifying reference model to help readers contextualise the role of paradata within a wider system of knowledge, practices and processes, and provides a vision for the future of the field. This guide to general principles and practice is ideal for researchers, students and data managers. This title is also available as open access on Cambridge Core.
American silk moth, Antheraea polyphemus Cramer 1775 (Lepidoptera: Saturniidae), native to North America, has potential significance in sericulture for food consumption and silk production. To date, the phylogenetic relationship and divergence time of A. polyphemus with its Asian relatives remain unknown. To end these issues, two mitochondrial genomes (mitogenomes) of A. polyphemus from the USA and Canada respectively were determined. The mitogenomes of A. polyphemus from the USA and Canada were 15,346 and 15,345 bp in size, respectively, with only two transitions and five indels. The two mitogenomes both encoded typical mitochondrial 37 genes. No tandem repeat elements were identified in the A+T-rich region of A. polyphemus. The mitogenome-based phylogenetic analyses supported the placement of A. polyphemus within the genus Antheraea, and revealed the presence of two clades for eight Antheraea species used: one included A. polyphemus, A. assamensis Helfer, A. formosana Sonan and the other contained A. mylitta Drury, A. frithi Bouvier, A. yamamai Guérin-Méneville, A. proylei Jolly, and A. pernyi Guérin-Méneville. Mitogenome-based divergence time estimation further suggested that the dispersal of A. polyphemus from Asia into North America might have occurred during the Miocene Epoch (18.18 million years ago) across the Berling land bridge. This study reports the mitogenome of A. polyphemus that provides new insights into the phylogenetic relationship among Antheraea species and the origin of A. polyphemus.
The heating effect of electromagnetic waves in ion cyclotron range of frequencies (ICRFs) in magnetic confinement fusion device is different in different plasma conditions. In order to evaluate the ICRF heating effect in different plasma conditions, we conducted a series of experiments and corresponding TRANSP simulations on the EAST tokamak. Both simulation and experimental results show that the effect of ICRF heating is poor at low core electron density. The decrease in electron density changes the left-handed electric field near the resonant layer, resulting in a significant decrease in the power absorbed by the hydrogen fundamental resonance. However, quite a few experiments must be performed in plasma conditions with low electron density. It is necessary to study how to make ICRF heating best in low electron density plasma. Through a series of simulation scans of the parallel refractive index (n//) of the ICRF antenna, it is concluded that the change of the ICRF antenna n// will lead to the change of the left-handed electric field, which will change the fundamental absorption of ICRF power by the hydrogen minority ions. Fully considering the coupling of ion cyclotron wave at the tokamak boundary and the absorption in the plasma core, optimizing the ICRF antenna structure and selecting appropriate parameters such as parallel refractive index, minority ion concentration, resonance layer position, plasma current and core electron temperature can ensure better heating effect in the ICRF heating experiments in the future EAST upgrade. These results have important implications for the enhancement of the auxiliary heating effect of EAST and other tokamaks.
A Chebyshev-distributed 1 × 8 beamforming network with improved phase flatness is presented, where four beams with constant beam pointing and low sidelobe levels (SLL) can be generated. It consists of two arbitrary-amplitude 4 × 4 Blass-like matrices and one 1 × 8 switch control circuit. The newly introduced 4 × 4 Blass-like matrices can obtain arbitrary amplitude and phase differences by adjusting the transmission coefficient and phase of each unit. Besides, four output phase differences can be generated by controlling the 1 × 8 switch control circuit. An example is implemented for validation and phase compensation method is adopted for minimizing the phase difference error within the operated bandwidth to maintain constant beam pointing. Measurements show that the prototype exhibits output amplitude ratios of 0.143:0.341: 0.71:1:1:0.71:0.341:0.143, which fits the Chebyshev distribution. Under the criterion of |S11| < −10 dB, an overlapped fractional bandwidth of 24.1% is obtained. In addition, from 5.5 to 6.1 GHz (10.3%), the maximum amplitude and phase difference errors are 1.5 dB and 15°, respectively. Finally, the proposed network is connected to a 1 × 8 array. Within 10.3% bandwidth, the SLLs of less than −20 dB are realized without beam-pointing deviation.