9 research outputs found

    The framework and analysis tool to evaluate the effect of product design to the performance of manufacturing system

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    Modeling of a manufacturing system enables one to identified the effects of key design parameters on the system performance d as a result to make correct decision. This paper proposes a manufacturing system modeling approach using a mathematical model approach based on real data porn a selected company, Ciriri Tegap Sdn. Bhd The model was used to improve the existing system utilization in relation to product design and system performance. The model incoyorates few parameters mch as utilization, cycle time, throughput, and batch size. The study also showed that the validity of developed model is good enough to apply and the maximum value of relative error is 30%, just below the limit value 32%. Iherefore, the nzodel developed in this study is a valuable alternative model in evaluating a manufacturing system

    Accelerated expansion from structure formation

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    We discuss the physics of backreaction-driven accelerated expansion. Using the exact equations for the behaviour of averages in dust universes, we explain how large-scale smoothness does not imply that the effect of inhomogeneity and anisotropy on the expansion rate is small. We demonstrate with an analytical toy model how gravitational collapse can lead to acceleration. We find that the conjecture of the accelerated expansion being due to structure formation is in agreement with the general observational picture of structures in the universe, and more quantitative work is needed to make a detailed comparison.Comment: 44 pages, 1 figure. Expanded treatment of topics from the Gravity Research Foundation contest essay astro-ph/0605632. v2: Added references, clarified wordings. v3: Published version. Minor changes and corrections, added a referenc

    Socio-demographic profiles and outcome of motorcycle related head injury in a Nigerian Tertiary Health Institution

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    Background: Motorcycle increasingly has been used for commercial transportation in many Nigerian cities with attendance increase in the rate of motorcycle crashes. Head injury is responsible for high morbidity and most mortality following such crashes. The aim of this study is to determine the socio-demographic characteristics of head injured victims of motorcycle crashes, severity of head injury and management outcome. Materials and Methods: A 1 year prospective study of head injured motorcyclists and pedestrians knocked down by motorcycle were carried out at University of Ilorin Teaching Hospital using a pre-designed proforma. Information collected included the age, gender, literacy level, alcohol consumption, license status, crash helmet use, Glasgow coma score and Glasgow outcome score. The IBM statistical package for social sciences (version 15.0) statistical package was used for statistical analysis. Results: A total of140 patients with the median age of 30 years (ranged 3-90 years) were studied. They comprised 115 (82%) males and 25 (18%) females. Most patients (66%) had at least secondary education. People of varying occupations were involved in a motorcycle crash. All riders were males and most (71.8%) were unlicensed. Only 5.8% of riders wore crash helmets at the time of the crash and they all had a favorable outcome. At both extremes of age (70 years) more patients were involved as pedestrians. The only socio-demographic variable that influence outcome of head injury was the patient age. Outcome was better in younger age group (P = 0.004). There was 26.4% mortality. Most, 23 (88.4%), of patients with severe head injury died and none of them had good recovery (P < 0.0001). Conclusion: Our findings demonstrated high mortality among non-crash helmet wearing motorcyclists with motor cycle related head injury. The outcome was significantly influenced by age and head injury severity

    Brillouin-Raman fiber laser with switchable wavelength spacing based on Brillouin pump distribution

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    A switchable multi-wavelength Brillouin-Raman fiber laser (MW-BRFL) is presented in this work. The MW-BRFL consists of a full-open linear cavity in which dispersion compensating fiber is employed as the gain medium for Brillouin and Raman amplification. The switching operation for single- and double-wavelength spacing MW-BRFL can be implemented by controlling Brillouin pump (BP) power distribution and direction that enters the laser cavity via two fiber-entry points. This is achievable by optimizing the splitting ratio of an optical coupler and the initial BP power. For the proposed laser setup, a 30/70 optical coupler was found to be the optimum. By setting the initial BP power at −3.0 dBm, 246 laser lines with 20-GHz frequency spacing were observed. The transformation to 10-GHz frequency spacing was attained by increasing the BP power to 11.8 dBm that resulted in 483 laser lines. All the counted laser lines had 3 dB peak power variation and were spread across a 38 nm bandwidth. In a nutshell, the proposed MW-BRFL is promising with respect to its performance, simplicity and flexibility

    Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

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    BackgroundEstimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period.Methods22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution.FindingsGlobal all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations.InterpretationGlobal adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic
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