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Simultaneous Distillation-Extraction for Manufacturing Ultra-High-Purity Electronic-Grade Octamethylcyclotetrasiloxane (D4)
No full textUltra-high-purity (UHP) electronic-grade octamethylcyclotetrasiloxane (D4) is the key precursor of low-dielectric constant (low-k) SiCOH films to manufacture integrated circuits (IC), meeting the stringent requirements of the rapidly developing semiconductor industry. Commonly, metallic impurities in D4 were removed by multiple unit operations of adsorption, filtration, and distillation, which could reduce the concentration of a single metallic impurity below 1 ppb. However, D4 with higher purity is required by semiconductor production due to an increase in transistor density. Herein, a novel method based on the integrated simultaneous distillation-extraction (SDE) was developed for manufacturing UHP electronic-grade D4. The lab and pilot scale experiments showed that the purity of water and D4 has a positive correlation. Based on the experimental data, a double-column process, consisting of azeotropic/extractive distillation column and precision distillation column with UNIQUAC method, was established to access the feasibility of scaling up the SDE process. According to the simulation results, D4 with the purity >99.999 wt.% and total metallic impurities (TMI) content below 1 ppb could be obtained using ultra-pure water. Keywords: Octamethylcyclotetrasiloxane (D4), Process integration, Simultaneous distillation-extraction, Electronic-Grade<br/
Home-working and e-communications with colleagues during COVID-19: impact on psychological health and productivity
No full textBACKGROUND: During the COVID-19 pandemic, there has been a wide-scale shift to home working for many employees in the UK. We hypothesised that during the lockdown, employees working from home would rely more heavily on work emails and other forms of e-communications to remain connected to colleagues and the work place. We additionally hypothesised that an increase in e-communications with colleagues outside of normal working hours would be associated with poorer health and productivity. METHODS: We surveyed N=204 full-time UK-based employees during October 2019 (pre-COVID) and during April 2020 (n=153, during-COVID). Ninety-three two participants indicated that they were working exclusively from home during-COVID, and were therefore included in analyses. RESULTS: Email volume was higher during-COVID than pre-COVID, and the use of instant messaging and video calls outside of normal working hours increased. Change in email engagement outside of normal working hours was not associated with health and productivity Change in email engagement outside of normal working hours was not associated with poorer health and productivity. However, increases in other forms of e-communications during leisure time was associated with poorer physical and mental health. CONCLUSIONS: A legacy of COVID-19 may be to accelerate a trend towards greater levels of home working, therefore understanding how to maintain health and productivity when working from home will be critical to ensure business continuity. Ours is the first study to suggest that increases in work-related video calls, instant messages and social media engagement outside of normal working hours may be detrimental to employee health and productivity
Bounds for the chi-square approximation of the power divergence family of statistics
No full textIt is well-known that each statistic in the family of power divergence statistics, across n trials and r classifications with index parameter λ ∈ R (the Pearson, likelihood ratio and Freeman-Tukey statistics correspond to λ = 1, 0, −1/2, respectively) is asymptotically chi-square distributed as the sample size tends to infinity. In this paper, we obtain explicit bounds on this distributional approximation, measured using smooth test functions, that hold for a given finite sample n, and all index parameters (λ > −1) for which such finite sample bounds are meaningful. We obtain bounds that are of the optimal order n¯¹. The dependence of our bounds on the index parameter λ and the cell classification probabilities is also optimal, and the dependence on the number of cells is also respectable. Our bounds generalise, complement and improve on recent results from the literature
Advancing Australian Public Health Initiatives Targeting Dementia Risk Reduction
No full textPublic health initiatives aim to improve health outcomes for populations by preventing disease and the health consequences of environmental hazards and natural or human-made disasters. Whilst public health initiatives have been successfully used to modify behaviours for chronic diseases yet many initiatives targeting reduced dementia risk in older adults suffer from conceptual and statistical flaws that greatly limit their usefulness. The limited success in modifying lifestyle dementia risk factors has led us to fall short in building a successful roadmap to dementia risk reduction. Here we argue for adopting a population-level, holistic approach to dementia risk reduction strategies across the lifespan. This approach is supplemented by 10 strategies that focus on improving social policies, harnessing existing policy, legislature and incentive schemes, and identifying feasible approaches to increase recreational and transport-related physical activity to creating best practice healthcare that supports healthy brain ageing for all.Key words: Health policy, health services, public health, gerontology, dementi
Stein factors for variance-gamma approximation in the Wasserstein and Kolmogorov distances
No full textWe obtain new bounds for the solution of the variance-gamma (VG) Stein equation that are of the correct form for approximations in terms of the Wasserstein and Kolmorogorov metrics. These bounds hold for all parameters values of the four parameter VG class. As an application we obtain explicit Wasserstein and Kolmogorov distance error bounds in a six moment theorem for VG approximation of double Wiener-It^o integrals
Endoscopic surveillance alone is feasible and safe in type I gastric neuroendocrine neoplasms less than 10mm in diameter
No full textPurposeType I gastric neuroendocrine neoplasms (g-NENs) have a low risk of metastasis and a generally favourable prognosis. Patients with small type I g-NENs (≤10mm) frequently require no treatment, whereas those with larger polyps usually undergo resection. We evaluated the safety and outcomes of endoscopic surveillance after no initial treatment in selected patients with type I g-NENs.MethodsRetrospective analysis of type I g-NEN patients across two European Neuroendocrine Tumour Society Centers of Excellence 2003-2019.ResultsFollowing initial assessment, 87 of 115 patients with type I g-NEN (75 with polyps ≤10mm) received no initial treatment and underwent endoscopic surveillance. 79/87 (91%) demonstrated no clinically meaningful change in tumour size or grade over a median 62 month follow up. Only two patients developed NEN progression that required a change in management and two other patients developed gastric adenocarcinoma/high grade dysplasia; all four initially had ≥11mm g-NENs.ConclusionsPatients with ≤10mm type I g-NENs were unlikely to develop clinically significant tumour progression and in most cases, resection was not needed. The endoscopic surveillance interval could therefore potentially be safely increased to every 2-3 years in such patients. However, lifelong surveillance is still advocated due to the additional risk of developing gastric adenocarcinoma
Latent class trajectory modelling: impact of changes in model specification
No full textLatent class trajectory models (LCTMs) are often used to identify subgroups of patients that are clinically meaningful in terms of longitudinal exposure and out¬come, e.g. drug response patterns. These models are increasingly applied in medicine and epidemiology. However, in many published studies, it is not clear whether the chosen models, where subgroups of patients are identified, represent real heterogeneity in the population, or whether any associations with clinically meaningful characteristics are accidental. In particular, we note an apparent over-reliance on lowest AIC or BIC values. While these are objective measures of goodness of fit, that can help identify the optimal number of subgroups, they are not sufficient on their own to fully evaluate a given trajectory model. Here we demonstrate how longitudinal latent class models can substantially change by making small modification in model specification, and the potential impact of this on the relationship to clinical outcomes. We show that the predicted trajectory patterns and outcome probabilities differ when pre-specified cubic versus linear shapes are tested on the same data. However, both could be interpreted to be the “correct” model. We emphasise that LCTMs, as all unsupervised approaches, are hypotheses generating, and should not be directly implemented in clinical practice without significant testing and validation
A scoping review of the literature on prosodic elements related to emotional speech in human-robot interaction
No full textBackground: Sentiment expression and detection are crucial for effective and empathetic human-robot interaction. Previous work in this field often focuses on non-verbal emotion expression, such as facial expressions and gestures. Less is known about which specific prosodic speech elements are required in human-robot interaction. Our research question was: what prosodic elements are related to emotional speech in human-computer/robot interaction?Methods: The scoping review was conducted in alignment with the Arksey and O’Malley methods. Literature was identified from the SCOPUS, IEEE Xplore, ACM Digital Library and PsycINFO databases in May 2021. After screening and de-duplication, data were extracted into an Excel coding sheet and summarised.Results: Thirteen papers, published from 2012 to 2020 were included in the review. The most commonly used prosodic elements were tone/pitch (n=8), loudness/volume (n=6) speech speed (n=4) and pauses (n=3). Non-linguistic vocalisations (n=1) were less frequently used. The prosodic elements were generally effective in helping to convey or detect emotion, but were less effective for negative sentiment (e.g., anger, fear, frustration, sadness and disgust).Discussion: Future research should explore the effectiveness of commonly used prosodic elements (tone, loudness, speed and pauses) in emotional speech, using larger sample sizes and real-life interaction scenarios. The success of prosody in conveying negative sentiment to humans may be improved with additional non-verbal cues (e.g., coloured light or motion). More research is needed to determine how these may be combined with prosody and which combination is most effective in human-robot affective interaction.Keywords: affective computing; speech; HRI; robotics; social robots; sentiment<br/
Effect of aging treatment on phase evolution and mechanical properties of selective laser melted Al-Mg-Er-Zr alloy
No full textEr and Zr modified Al-Mg alloy was manufactured by selective laser melting. The effect of aging treatment on phase evolution and mechanical properties of alloy has been studied. The results show that bimodal grain structures (2.8±1.1 μm) could be obtained, thanks to the Al3Zr primary phases promoting the formation of equiaxed grains (0.8±0.3 μm) at the boundary of molten pool. During the aging of 375 ℃, Al3(Er,Zr) particles with the size of 2-5 nm were produced via synergistic precipitation of Er and Zr, which would greatly improve the strength and reach 510±9 MPa. At the same time, the Mg-rich phase was dissolved, the Mn-rich phase was precipitated, and dislocations could accelerate the diffusion of solute atoms during the evolution of the phases
Multi-objective QUBO Solver: Bi-objective Quadratic Assignment Problem
No full textQuantum and quantum-inspired optimisation algorithms are designed to solve problems represented in binary, quadratic and unconstrained form. Combinatorial optimisation problems are therefore often formulated as Quadratic Unconstrained Binary Optimisation Problems (QUBO) to solve them with these algorithms. Moreover, these QUBO solvers are often implemented using specialised hardware to achieve enormous speedups, e.g. Fujitsu’s Digital Annealer (DA) and D-Wave’s Quantum Annealer. However, these are single-objective solvers, while many real-world problems feature multiple conflicting objectives. Thus, a common practice when using these QUBO solvers is to scalarise such multi-objective problems into a sequence of single-objective problems. Due to design trade-offs of these solvers, formulating each scalarisation may require more time than finding a local optimum.We present the first attempt to extend the algorithm supporting a commercial QUBO solver as a multi-objective solver that is not based on scalarisation. The proposed multi-objective DA algorithm is validated on the bi-objective Quadratic Assignment Problem. We observe that algorithm performance significantly depends on the archiving strategy adopted, and that combining DA with non-scalarisation methods to optimise multiple objectives outperforms the current scalarised version of the DA in terms of final solution quality