301 research outputs found
A component-based macro-mechanical model for inter-module connections in steel volumetric buildings
Inter-module connections (IMC) are a research focus closely related to the robustness of steel volumetric buildings (VB). Many IMC have been proposed by numerous researchers and engineers, experimentally tested and numerically studied using finite element models. However, there are insufficient IMC macro models available, which imposes challenges for engineers to construct a global numerical VB model. Hence, this study aims to close the gap with a component-based macro-mechanical model for the macro-modelling of IMC in steel VB. In this paper, a comprehensive IMC database was collected to identify and characterise the active components. Two types of macro-mechanical models (H-shape and Q-shape) consisting of P-V-M links have been proposed and a novel uplifting mechanism has been derived for a typical IMC (bolted tie plate with shear key). The proposed macro-mechanical model and other existing macro-models were then compared with existing pushover experiments from an IMC subassembly. The proposed macro-mechanical model shows a good match to the existing experimental results, and it is adaptable to existing IMC.</p
Behavior of wire arc additively manufactured 316L austenitic stainless steel single shear bolted connections
This paper aims to investigate the behavior of single shear bolted connections made of wire arc additively manufactured 316L austenitic stainless steel. A set of 44 wire arc additive manufacturing (WAAM) 316L austenitic stainless steel single shear bolted connections were included with consideration of various bolt positions, surface conditions and loading orientations respective to the printing layer direction. The geometric dimensions of the WAAM austenitic stainless steel plates were measured with the assistance of non-contact 3D laser scanning prior to tensile testing. Monotonic tensile tests were carried out to investigate the load-deformation responses, failure patterns and resistances determined by both the deformation and strength criteria of the single shear bolted connections. The effects of geometric and printing parameters on the single shear bolted connections were analyzed. Due to the absence of codified design provisions for WAAM austenitic stainless steel bolted connections, the suitability of the existing design rules originally developed for traditionally manufactured carbon steel and stainless steel bolted connections was examined. Design resistances calculated by the Eurocode 3 (prEN 1993-1-8 and prEN 1993-1-4), the American Specification (ANSI/AISC 370-21) as well as the prevalent design recommendations proposed in existing literature were compared with the obtained experimental results. It is shown that the abovementioned design methods offer conservative predictions for the resistances of WAAM 316L austenitic stainless steel single shear bolted connections. Further study is needed to improve the accuracy of design resistance predictions
Local-distortional interaction in cold-formed steel lipped channel beams under uniform bending: Experimental investigation
This paper describes a test campaign concerning the behavior and strength of cold-formed steel (CFS) lipped channel (LC) beams experiencing local-distortional (L-D) interaction made of G450-G500 high-strength steel grades. This investigation involves the performance of 20 tests on simply supported beams arranged in a “back-to-back” configuration, subjected to four-point major-axis bending and laterally restrained at the loading points. All tested specimens failed in the expected L-D interactive modes and exhibited critical distortional-to-local buckling moment ratios ranging between 1.09 and 1.46 (i.e., prone to “true L-D interaction”). The experiment results obtained and reported consist of beam (i) moment-displacement equilibrium paths, (ii) photos evidencing the evolution of the beam deformed configurations along those equilibrium paths (including the failure modes) and (iii) failure moments − it is found that these results are in good agreement with recently performed numerical simulations. Finally, the experimental failure moments obtained are compared with their estimates provided by the (i) currently codified Direct Strength Method (DSM) strength curves associated with local and distortional failures, and (ii) other available DSM-based design approaches developed to handle L-D interactive failures. This comparison provides solid evidence that the CFS specifications must include a DSM-based design approach able to handle beam L-D interactive failures − the current local and distortional design curves clearly overestimate all the experimental failure moments.The authors gratefully acknowledge the support of M Metal Pte Ltd in Singapore, for supplying the cold-formed steel beam specimens tested at The University of Hong Kong
Secondhand smoke exposure (SHS) and health-related quality of life (HRQoL) in Chinese never smokers in Hong Kong
Objective: The evidence on the effect of secondhand smoke (SHS) on Health Related Quality of Life (HRQoL) is limited. We examined the relation between SHS and HRQoL among Chinese in Hong Kong. Methods: Adult never smokers from a probability sample of three cross-sectional waves (2010, 2012, 2013) of The Hong Kong Family and Health Information Trends Survey who completed the Cantonese-version of Short-Form 12 Health Survey Questionnaire (SF12v2) were included in the data analysis conducted in 2014. Models were used to examine associations of SHS with SF12 domains and summary scores of Physical (PCS12) and Mental Component (MCS12) with subgroups analysis by SHS locations. Results: After adjustments, SHS was associated with lower scores on all SF12 domains except physical functioning. PCS12 (regress coefficient=−0.76, 95% CI −1.34 to −0.17) and MCS12 (regress coefficient=−1.35, 95% CI −2.06 to −0.64) were lower in those with SHS exposure than those non-exposed. Those exposed to SHS in outdoor public places had lower scores on most SF12 domains and PSC12 and MCS12. SHS exposure in one's home and workplace was associated with lower scores on role physical, body pain and role emotional while SHS exposure in friends’ homes was additionally associated with lower social functioning and mental health scores. Lower MCS12 was associated with SHS exposure at all locations except one's home. Conclusions: Our study showed that SHS exposure, particularly in outdoor public places, was associated with decreased HRQoL. It can provide new evidence for stronger smoke-free policies on public places and promoting smoke-free homes
Characterization of Respiratory Systems Among Youth Using Heated Tobacco Products in Hong Kong
Importance Heated tobacco products (HTPs) are promoted as less harmful than combustible cigarettes but epidemiological evidence is scarce, especially in youth. Objective To investigate the associations of persistent respiratory symptoms with HTP use, cigarette use, and dual use among Hong Kong youth. Design, Setting, and Participants This was a territorywide cross-sectional school-based survey conducted from October 2018 to July 2019 using an anonymous questionnaire. Schools were randomly invited from a proportionate stratified sample in all 18 districts of Hong Kong. Poisson regression models using generalized estimating equations yielded adjusted prevalence ratios (APRs) of respiratory symptoms in (1) former and current HTP (vs never) users in the whole sample and stratified by cigarette use status and (2) exclusive HTP and dual users vs exclusive cigarette users. Statistical analysis was performed from October 2020 to March 2021. Exposures Former and current use of cigarettes, HTPs, e-cigarettes, and other tobacco products. Main Outcomes and Measures Respiratory symptoms for 3 consecutive months in the past 12 months
Elemental topological Dirac semimetal: {\alpha}-Sn on InSb(111)
Three-dimensional (3D) topological Dirac semimetals (TDSs) are rare but
important as a versatile platform for exploring exotic electronic properties
and topological phase transitions. A quintessential feature of TDSs is 3D Dirac
fermions associated with bulk electronic states near the Fermi level. Using
angle-resolved photoemission spectroscopy (ARPES), we have observed such bulk
Dirac cones in epitaxially-grown {\alpha}-Sn films on InSb(111), the first such
TDS system realized in an elemental form. First-principles calculations confirm
that epitaxial strain is key to the formation of the TDS phase. A phase diagram
is established that connects the 3D TDS phase through a singular point of a
zero-gap semimetal phase to a topological insulator (TI) phase. The nature of
the Dirac cone crosses over from 3D to 2D as the film thickness is reduced
Successful Radiofrequency Catheter Ablation for Wolff-Parkinson-White Syndrome Within the Neck of a Coronary Sinus Diverticulum
Posteroseptal accessory pathways are often associated with coronary sinus diverticula. These diverticula contain myocardial coats which serve as a bypass tract. We report a 54-year-old woman who underwent radiofrequency (RF) catheter ablation for Wolff-Parkinson-White (WPW) syndrome. The surface electrocardiography (ECG) demonstrated pre-excitation, indicating a posteroseptal accessory pathway. A catheter ablation via a transaortic approach failed to ablate the accessory pathway. Coronary sinus venography revealed the presence of a diverticulum near the ostium. An electrogram in the neck of the diverticulum showed the coronary sinus myocardial extension potential, which was successfully ablated by delivery of RF energy
Nurses' knowledge of universal health coverage for inclusive and sustainable elderly care services
Objectives: to explore nurses' knowledge of universal health coverage (UHC) for inclusive and sustainable development of elderly care services. Method: this was a cross-sectional survey. A convenience sample of 326 currently practicing enrolled nurses (EN) or registered nurses (RN) was recruited. Respondents completed a questionnaire which was based on the implementation strategies advocated by the WHO Global Forum for Governmental Chief Nursing Officers and Midwives (GCNOMs). Questions covered the government initiative, healthcare financing policy, human resources policy, and the respondents' perception of importance and contribution of nurses in achieving UHC in elderly care services. Results: the knowledge of nurses about UHC in elderly care services was fairly satisfactory. Nurses in both clinical practice and management perceived themselves as having more contribution and importance than those in education. They were relatively indifferent to healthcare policy and politics. Conclusion: the survey uncovered a considerable knowledge gap in nurses' knowledge of UHC in elderly care services, and shed light on the need for nurses to be more attuned to healthcare policy. The educational curriculum for nurses should be strengthened to include studies in public policy and advocacy. Nurses can make a difference through their participation in the development and implementation of UHC in healthcare services.Objetivos: explorar o conhecimento dos enfermeiros sobre a cobertura universal de saúde (CUS) para o desenvolvimento inclusivo e sustentável de serviços de saúde a idosos. Método: estudo transversal. Foi recrutada uma amostra de conveniência de 326 enrolled nurses (EN) ou registered nurses (RN). Os entrevistados responderam a um questionário com base nas estratégias de implementação preconizadas pelo Fórum Global da OMS para Governmental Chief Nursing Officers and Midwives (GCNOMs). As perguntas abordavam iniciativas do governo, políticas de financiamento da saúde, políticas de recursos humanos e percepção dos entrevistados sobre a importância e contribuição do enfermeiro no alcance da CUS em serviços de cuidados a idosos. Resultado: o conhecimento de enfermeiros sobre a CUS em serviço de atenção ao idoso foi razoavelmente satisfatório. Enfermeiros tanto da prática clínica como da gestão perceberam-se contribuindo mais e tendo mais importância do que aqueles que trabalham na educação. Eles eram relativamente indiferentes à política de saúde e à política. Conclusão: a pesquisa revelou uma lacuna de conhecimento considerável no conhecimento da CUS pelos enfermeiros nos serviços de cuidados a idosos e evidenciou a necessidade de enfermeiros terem mais sintonia com a política de saúde. O currículo de formação para preparar os enfermeiros deve ser reforçado para incluir estudos em política pública e advocacia. Os enfermeiros podem fazer a diferença por meio de sua participação no desenvolvimento e implementação da CUS nos serviços de saúde.Objetivos: explorar los conocimientos que tienen las enfermeras sobre la cobertura universal de salud (CUS) para el desarrollo inclusivo y sostenible de servicios para el cuidado de adultos mayores. Método: se utilizó una encuesta transversal. Se formó una muestra de conveniencia de 326 enrolled nurses (EN) o registered nurses (RN) que actualmente estuvieran ejerciendo. Los encuestados respondieron a un cuestionario basado en las estrategias de implementación apoyadas por el WHO Global Forum for Government Chief Nursing and Midwifery Officers (WGFGCNO). Las preguntas abarcaban la iniciativa del gobierno, políticas de financiamiento de la salud, las políticas de recursos humanos y la percepción de los encuestados sobre la importancia y la contribución de las enfermeras en el logro de la CUS en los servicios de cuidado para adultos mayores. Resultados: el conocimiento de las enfermeras sobre CUS en el servicio de cuidado para los adultos mayores fue bastante satisfactorio. Tanto las enfermeras de práctica clínica y como las de gestión perciben tener un mayor aporte e importancia que las de que están en educación. Tenían un punto de vista relativamente indiferente a la política sanitaria y la política. Conclusión: la encuesta descubrió una considerable brecha en el conocimiento de las enfermeras sobre CUS en los servicios de cuidado para adultos mayores y puso de manifiesto la necesidad de que las enfermeras estén más en sintonía con la política sanitaria. El plan de estudios para la preparación de las enfermeras debe fortalecerse para incluir estudios en las políticas públicas y promoción. Las enfermeras pueden hacer una diferencia a través de su participación en el desarrollo e implementación de CUS en los servicios de salud
Short version of the Smartphone Addiction Scale in Chinese adults: Psychometric properties, sociodemographic, and health behavioral correlates
Background and aims: Problematic smartphone use (PSU) is an emerging but understudied public health issue. Little is known about the epidemiology of PSU at the population level. We evaluated the psychometric properties of the Smartphone Addiction Scale – Short Version (SAS-SV) and examined its associated sociodemographic factors and health behaviors in Chinese adults in Hong Kong. Methods: A random sample of 3,211 adults aged ≥18 years (mean ± SD: 43.3 ± 15.7, 45.3% men) participated in a population-based telephone survey in Hong Kong and completed the Chinese SAS-SV. Multivariable linear regressions examined the associations of sociodemographic factors, health behaviors, and chronic disease status with SAS-SV score. Data were weighted by age, sex, and education attainment distributions of the Hong Kong general population. Results: The Chinese SAS-SV is internally consistent (Cronbach’s α = .844) and stable over 1 week (intraclass correlation coefficient = .76, p < .001). Confirmatory factor analysis supported a unidimensional structure established by previous studies. The weighted prevalence of PSU was 38.5% (95% confidence interval: 36.9%, 40.2%). Female sex, younger age, being married/cohabitated or divorced/separated (vs. unmarried), and lower education level were associated with a higher SAS-SV score (all ps <.05). Current smoking, weekly to daily alcohol drinking, and physical inactivity predict greater PSU after controlling for sociodemographic factors and mutual adjustment. Discussion and conclusions: The Chinese SAS-SV was found valid and reliable for assessing PSU in Hong Kong adults. Several sociodemographic and health behavioral factors were associated with PSU at the population level, which may have implication for prevention of PSU and future research
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