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Performance of a novel structural insulated panel in tropical climates : experimental and numerical studies
No full textThis article investigates experimentally and numerically the thermal performance of a new type of structural insulated panel (SIP) termed ‘UWall’. The panel core consists of an ad-hoc waffle skeleton of Expanded Polystyrene (EPS), EPS beads mixed with cement mortar (Portland cement type I and recycled concrete aggregate), and two external water-proof cement boards. The experimental programme examined the panels in three Phases. In Phase 1, 200×200×100 mm block specimens were exposed to a temperature of 70°C for 12 hrs. It was found that the new UWall specimens had a better thermal performance (by up to 20%) over other types of walls typically used in house construction in Southeast Asia such as Mon block wall. In Phase 2, five scaled-down house units (1.5×1.5×2.8 m) were built in Thailand. Temperature and relative humidity outside/inside the units were continuously monitored for 7 days during the summer season. It was found that the new UWall has a good thermal resistance, reducing temperatures by up to 4°C compared to mon-block wall material. The house units were subsequently modelled in Abaqus® software, and the modelling approach proved accurate (within 10%) at simulating the thermal performance of the house units. UWall panels were also tested in bending to determine their structural capacity. It was found that the panels can be safely used as load-bearing walls for single-storey houses. Design charts are then proposed and used to design and build a full-scale house in Phase 3. In Phase 3, a 10×7 m full-scale single-storey house was built using the new UWall panels. Based on results from bioclimatic charts, it was found that daytime temperature and humidity in the full-scale house were deemed as uncomfortable. However, if air movement was provided, the house remained within the comfortable zone at all times. New design charts for full-scale houses with UWall are proposed to meet a desired user-comfort level. This study is expected to promote the use of SIPs in house construction in tropical climates, which in turn is envisaged to save energy and make construction more sustainable
A beta-Poisson model for infectious disease transmission
Get PDFOutbreaks of emerging and zoonotic infections represent a substantial threat to human health and well-being. These outbreaks tend to be characterised by highly stochastic transmission dynamics with intense variation in transmission potential between cases. The negative binomial distribution is commonly used as a model for transmission in the early stages of an epidemic as it has a natural interpretation as the convolution of a Poisson contact process and a gamma-distributed infectivity. In this study we expand upon the negative binomial model by introducing a beta-Poisson mixture model in which infectious individuals make contacts at the points of a Poisson process and then transmit infection along these contacts with a beta-distributed probability. We show that the negative binomial distribution is a limit case of this model, as is the zero-inflated Poisson distribution obtained by combining a Poisson-distributed contact process with an additional failure probability. We assess the beta-Poisson model’s applicability by fitting it to secondary case distributions (the distribution of the number of subsequent cases generated by a single case) estimated from outbreaks covering a range of pathogens and geographical settings. We find that while the beta-Poisson mixture can achieve a closer to fit to data than the negative binomial distribution, it is consistently outperformed by the negative binomial in terms of Akaike Information Criterion, making it a suboptimal choice on parsimonious grounds. The beta-Poisson performs similarly to the negative binomial model in its ability to capture features of the secondary case distribution such as overdispersion, prevalence of superspreaders, and the probability of a case generating zero subsequent cases. Despite this possible shortcoming, the beta-Poisson distribution may still be of interest in the context of intervention modelling since its structure allows for the simulation of measures which change contact structures while leaving individual-level infectivity unchanged, and vice-versa
Translating survivor-centredness into pedagogical approaches to training on sexual violence in conflict and emergency settings : a case study
Get PDFTo encourage further interrogation of the language of “survivor-centredness” in the field of conflict-related sexual violence, this article offers a case study of efforts to build and intensify more survivor-centred pedagogy for use in the training of humanitarian workers seeking to address sexual violence in conflict and emergency settings. Set against the backdrop of a literature review of existing usages, it builds on key aspects of an earlier evaluation in which all three authors were involved in different capacities
Developing preventative strategies to mitigate thermal runaway in NMC532-graphite cylindrical cells using forensic simulations
Get PDFThe ubiquitous deployment of Li-ion batteries (LIBs) in more demanding applications has reinforced the need to understand the root causes of thermal runaway. Herein, we perform a forensic simulation of a real-case failure scenario, using localised heating of Li(Ni0.5Mn0.3Co0.2)O2 versus graphite 18650 cylindrical cells. This study determined the localised temperatures that would lead to venting and thermal runaway of these cells, as well as correlating the gases produced as a function of the degradation pathway. Catastrophic failure, involving melting (with internal cell temperatures exceeding 1085 °C), deformation and ejection of the cell componentry, was induced by locally applying 200 °C and 250 °C to a fully charged cell. Conversely, catastrophic failure was not observed when the same temperatures were applied to the cells at a lower state of charge (SOC). This work highlights the importance of SOC, chemistry and heat in driving the thermal failure mode of Ni-rich LIB cells, allowing for a better understanding of battery safety and the associated design improvements
Challenges in conducting feminist critical discourse analysis on social media : stereotyping sportswomen in China’s sports fandom
No full textThis case study discusses the application of feminist critical discourse analysis (FCDA) in social media data analysis. The discussion is based primarily on a case study that uses FCDA to explore the stereotyping of sportswomen in China’s social-mediated sports fandom. It emphasizes the challenges and practical considerations involved in the design and implementation of the case study. In doing so, it provides insights into the research process and methodology, highlighting how FCDA helps to critically examine the male gaze and gender power dynamics within social-mediated sports fandom. By reading this case study, students will learn how to incorporate a feminist perspective into critical discourse studies in various research contexts. It is hoped that this case study will contribute to a broader understanding of the methodologic issues associated with FCDA research practices
Real-time rheological monitoring with the smart stirrer
Get PDFThis paper presents an approach for wireless real-time measurements of dynamic viscosity in the range of 50-1000 mPa·s utilising a laboratory hotplate in conjunction with the Smart Stirrer device. The Smart Stirrer, an innovative tool resembling a conventional magnetic stirrer enhanced with embedded System-on-Chip (SoC) Bluetooth Low Energy (BLE) module, inertial measurement unit (IMU) and magnetometer sensors, serving as a platform for viscosity monitoring. The principle of measurement based on the interaction between the magnetic field of the hotplate’s magnet and the Smart Stirrer’s internal magnets, with variations in a liquid viscosity impacting the rotational dynamics of the Stirrer and measured by the sensors. The paper details the experimental setup, data acquisition, and analysis procedures, demonstrating the capability of the system to accurately and non-invasively measure the viscosity of various liquid solutions in real-time. The method addresses the practical limitations of existing methods and offers a integrative approach for monitoring in-situ rheological properties in laboratory settings. It stands out for its simplicity, ease of integration, and potential for broader applications, making it a valuable tool in various fields requiring fluid property measurements
The college wage premium in the UK : decline and fall?
No full textWe exploit two longitudinal cohort studies for birth cohorts of 1970 and 1990 to assess the change in the UK college wage premium (CWP) for those aged 25-26. After controlling for a rich set of covariates, we find evidence of a decline in the average CWP from 18% to 8%. The extent of the fall is common to men and women; hence, it is not driven by changes in sex composition over this time period. Our results contrast with previous findings of relative stability in the CWP over time. In complementary analysis, we exploit Labour Force Survey (LFS) data from 1995 to 2019 to explore the timing of the fall in the CWP and to assess whether the decline is specific to particular birth cohorts or age ranges of workers
β Pictoris b through the eyes of the upgraded CRIRES
No full textContext. High-resolution spectrographs fed by adaptive optics (AO) provide a unique opportunity to characterize directly imaged exoplanets. Observations with such instruments allow us to probe the atmospheric composition, spin rotation, and radial velocity of the planet, thereby helping to reveal information on its formation and migration history. The recent upgrade of the Cryogenic High-Resolution Infrared Echelle Spectrograph (CRIRES+) at the VLT makes it a highly suitable instrument for characterizing directly imaged exoplanets.
Aims. In this work, we report on observations of β Pictoris b with CRIRES+ and use them to constrain the planets atmospheric properties and update the estimation of its spin rotation.
Methods. The data were reduced using the open-source pycrires package. We subsequently forward-modeled the stellar, planetary, and systematic contribution to the data to detect molecules in the planet’s atmosphere. We also used atmospheric retrievals to provide new constraints on its atmosphere.
Results. We confidently detected water and carbon monoxide in the atmosphere of β Pictoris b and retrieved a slightly sub-solar carbon-to-oxygen ratio, which is in agreement with previous results. The interpretation is hampered by our limited knowledge of the C/O ratio of the host star. We also obtained a much improved constraint on its spin rotation of 19.9 ± 1.0 kms−1, which gives a rotation period of 8.7 ± 0.8 h, assuming no obliquity. We find that there is a degeneracy between the metallicity and clouds, but this has minimal impact on the retrieved C/O, υ sin i, and radial velocity. Our results show that CRIRES+ is performing well and stands as a highly useful instrument for characterizing directly imaged planets
Cross-age contrastive learning for age-invariant face recognition
Get PDFCross-age facial images are typically challenging and expensive to collect, making noise-free age-oriented datasets relatively small compared to widely-used large-scale facial datasets. Additionally, in real scenarios, images of the same subject at different ages are usually hard or even impossible to obtain. Both of these factors lead to a lack of supervised data, which limits the versatility of supervised methods for age-invariant face recognition, a critical task in applications such as security and biometrics. To address this issue, we propose a novel semi-supervised learning approach named Cross-Age Contrastive Learning (CACon). Thanks to the identity-preserving power of recent face synthesis models, CACon introduces a new contrastive learning method that leverages an additional synthesized sample from the input image. We also propose a new loss function in association with CACon to perform contrastive learning on a triplet of samples. We demonstrate that our method not only achieves state-of-the-art performance in homogeneous-dataset experiments on several age-invariant face recognition benchmarks but also outperforms other methods by a large margin in cross-dataset experiments
Microstructural alterations of the hypothalamus in Parkinson's disease and probable REM sleep behavior disorder
Get PDFWhether there is hypothalamic degeneration in Parkinson's disease (PD) and its association with clinical symptoms and pathophysiological changes remains controversial. We aimed to quantify microstructural changes in hypothalamus using a novel deep learning-based tool in patients with PD and those with probable rapid-eye-movement sleep behavior disorder (pRBD). We further assessed whether these microstructural changes associated with clinical symptoms and free thyroxine (FT4) levels. This study included 186 PD, 67 pRBD, and 179 healthy controls. Multi-shell diffusion MRI were scanned and mean kurtosis (MK) in hypothalamic subunits were calculated. Participants were assessed using Unified Parkinson's Disease Rating Scale (UPDRS), RBD Questionnaire-Hong Kong (RBDQ-HK), Hamilton Depression Rating Scale (HAMD), and Activity of Daily Living (ADL) Scale. Additionally, a subgroup of PD (n = 31) underwent assessment of FT4. PD showed significant decreases of MK in anterior-superior (a-sHyp), anterior-inferior (a-iHyp), superior tubular (supTub), and inferior tubular hypothalamus when compared with healthy controls. Similarly, pRBD exhibited decreases of MK in a-iHyp and supTub. In PD group, MK in above four subunits were significantly correlated with UPDRS-I, HAMD, and ADL. Moreover, MK in a-iHyp and a-sHyp were significantly correlated with FT4 level. In pRBD group, correlations were observed between MK in a-iHyp and UPDRS-I. Our study reveals that microstructural changes in the hypothalamus are already significant at the early neurodegenerative stage. These changes are associated with emotional alterations, daily activity levels, and thyroid hormone levels. [Abstract copyright: Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.