25 research outputs found

    Inductive contactless energy transfer systems for residential areas

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    In recent years, contactless energy transfer systems have been developed and investigated widely. As evident, the transfer energy is performed without physical connection. This technology is classified according to power level and place of use. However, the most commonly used one is inductive contactless energy transfer system due to its higher efficiency. The inductive contactless system is responsible to deliver the electrical energy to the loads by means of a long winding loop and sliding transformers. In this system, the output converter and load are directly connected to the secondary side of transformer. Moreover, the secondary side transformer has the capability to move along the primary winding loop. According to this capability, and also possibility to construct long contactless system, it can be used as an electrical energy delivery system for mobile receivers. Also, the ICET technologies improve the safety of the final user by means of the elimination of electrical shocks. It is resulted from using a high-frequency resonant transformer which provides electrical isolation. This feature is particularly important in wet environments such as in swimming pools, gardens and bathrooms. Therefore, it is a good alternative system for implementing in the residential area instead of conventional systems. Implementation of the inductive contactless system in residential area presents several challenges. In this dissertation, several solutions are presented and discussed. In the first chapter, the concept of the contactless energy transfer system is explained. Also, the chapter classifies the contactless system according to the technology and the output power. In chapter two, a new adaptive control algorithm for the fully-controlled contactless energy transfer system is presented. The new adaptive algorithm operates dynamically with the load changes, resulting in maximum efficiency in all the load conditions. Moreover, the mathematical framework of the contactless system with new adaptive algorithm is presented. In chapter three, a partially-controlled inductive contactless system as an alternative to the fully-controlled topology is introduced. The features of the new topology are analyzed by considering several modulation techniques, including frequency modulation, phase modulation and quantum modulation. The performance of the new topology is evaluated and the best modulation technique is identified. The chapter is finished with the design of the new topology with the best modulation technique. In chapter four, the analysis, design and implementation of a simple and cost-effective technique to supply the residential contactless energy transfer system with multiple mobile loads is presents. The topology is based on the cascaded connection of a closed-loop buck converter and a high frequency resonant inverter operating in open loop which is loaded by several output passive rectifiers. The proposed system includes a sliding transformer to supply the mobile loads, leading to a safe and flexible location of loads. The theoretical analysis and design of the proposed system is based on a mathematical model derived using the first harmonic approximation. Selected experimental results are included to verify the system features. Finally, the dissertation concludes with remarks regarding the results.En los últimos años, los sistemas de transmisión de energía sin contacto han sido ampliamente investigados y desarrollados. Como es evidente, en estos la transmisión de energía se realiza sin conexión física. Esta tecnología se suele clasificar de acuerdo al nivel de potencia y el lugar de utilización. Sin embargo, los más usados son los sistemas inductivos de trasmisión de energía sin contacto (Inductive contactless energy transfer systems, ICET) debido a su alta eficiencia. Los sistemas ICET envían la energía eléctrica a las cargas a través de grandes bobinados y transformadores sliding. En estos sistemas, la salida del convertidor y las cargas están directamente conectadas al lado secundario del transformador. Este, tiene la capacidad de moverse a través del bobinado primario. Debido a esta capacidad y a la posibilidad de construir sistemas de gran tamaño, pueden ser usados como sistemas de suministro de energía para receptores móviles. Por otro lado, las tecnologías ICET mejoran la seguridad de los usuarios finales ya que eliminan el riesgo de electrocución, como resultado del uso de transformadores resonantes de alta frecuencia que proveen un aislamiento eléctrico. Esta característica es particularmente importante en ambientes húmedos como las piscinas, jardines y baños. Además, es una buena alternativa para la implementación residencial, en lugar de los sistemas convencionales. La implementación de sistemas ICET en áreas residenciales presenta ciertos retos. En esta tesis de doctorado, se presentan diversas soluciones a estos. En el primer capítulo, el concepto de sistemas de transmisión de energía sin contacto es explicado y se presenta una clasificación de acuerdo al nivel de potencia. En el segundo capítulo, se propone un algoritmo de control adaptativo para sistemas de transmisión de energía sin contacto totalmente controlados. Este algoritmo adaptativo opera dinámicamente con los cambios de carga, alcanzando la máxima eficiencia ante diferentes condiciones de carga. En el capítulo se describe el modelado matemático del algoritmo propuesto. En el tercer capítulo, se introduce un sistema sin contacto inductivo parcialmente controlado como alternativa a la topología totalmente controlada. Se analizan las características de esta nueva topología considerando diferentes técnicas de modulación, incluyendo la modulación de frecuencia, la modulación de fase y la modulación Quantum. Luego, se evalúa el desempeño de esta nueva topología y de identifica la técnica de modulación más adecuada. Finalmente, se presenta el diseño de la nueva topología con la técnica de modulación seleccionada. En el cuarto capítulo se presenta el análisis, diseño e implementación de una técnica simple y efectiva en términos de costo para el suministro energía inalámbrica residencial con múltiples cargas móviles. La topología se basa en una conexión en cascada de un convertidor buck de lazo cerrado y de un inversor resonante de alta frecuencia operando en lazo abierto, que es cargado con varios rectificadores pasivos. El sistema propuesto incluye un transformador sliding para abastecer las cargas móviles, lo que permite una ubicación flexible y segura de las mismas. El análisis teórico y el diseño del sistema propuesto se basan en modelos matemáticos derivados del uso de la aproximación del primer armónico. Se incluyen resultados experimentales para verificar las características del sistema. Finalmente, se presentan las conclusiones más importantes de los resultados obtenido

    Inductive contactless energy transfer systems for residential areas

    Get PDF
    In recent years, contactless energy transfer systems have been developed and investigated widely. As evident, the transfer energy is performed without physical connection. This technology is classified according to power level and place of use. However, the most commonly used one is inductive contactless energy transfer system due to its higher efficiency. The inductive contactless system is responsible to deliver the electrical energy to the loads by means of a long winding loop and sliding transformers. In this system, the output converter and load are directly connected to the secondary side of transformer. Moreover, the secondary side transformer has the capability to move along the primary winding loop. According to this capability, and also possibility to construct long contactless system, it can be used as an electrical energy delivery system for mobile receivers. Also, the ICET technologies improve the safety of the final user by means of the elimination of electrical shocks. It is resulted from using a high-frequency resonant transformer which provides electrical isolation. This feature is particularly important in wet environments such as in swimming pools, gardens and bathrooms. Therefore, it is a good alternative system for implementing in the residential area instead of conventional systems. Implementation of the inductive contactless system in residential area presents several challenges. In this dissertation, several solutions are presented and discussed. In the first chapter, the concept of the contactless energy transfer system is explained. Also, the chapter classifies the contactless system according to the technology and the output power. In chapter two, a new adaptive control algorithm for the fully-controlled contactless energy transfer system is presented. The new adaptive algorithm operates dynamically with the load changes, resulting in maximum efficiency in all the load conditions. Moreover, the mathematical framework of the contactless system with new adaptive algorithm is presented. In chapter three, a partially-controlled inductive contactless system as an alternative to the fully-controlled topology is introduced. The features of the new topology are analyzed by considering several modulation techniques, including frequency modulation, phase modulation and quantum modulation. The performance of the new topology is evaluated and the best modulation technique is identified. The chapter is finished with the design of the new topology with the best modulation technique. In chapter four, the analysis, design and implementation of a simple and cost-effective technique to supply the residential contactless energy transfer system with multiple mobile loads is presents. The topology is based on the cascaded connection of a closed-loop buck converter and a high frequency resonant inverter operating in open loop which is loaded by several output passive rectifiers. The proposed system includes a sliding transformer to supply the mobile loads, leading to a safe and flexible location of loads. The theoretical analysis and design of the proposed system is based on a mathematical model derived using the first harmonic approximation. Selected experimental results are included to verify the system features. Finally, the dissertation concludes with remarks regarding the results.En los últimos años, los sistemas de transmisión de energía sin contacto han sido ampliamente investigados y desarrollados. Como es evidente, en estos la transmisión de energía se realiza sin conexión física. Esta tecnología se suele clasificar de acuerdo al nivel de potencia y el lugar de utilización. Sin embargo, los más usados son los sistemas inductivos de trasmisión de energía sin contacto (Inductive contactless energy transfer systems, ICET) debido a su alta eficiencia. Los sistemas ICET envían la energía eléctrica a las cargas a través de grandes bobinados y transformadores sliding. En estos sistemas, la salida del convertidor y las cargas están directamente conectadas al lado secundario del transformador. Este, tiene la capacidad de moverse a través del bobinado primario. Debido a esta capacidad y a la posibilidad de construir sistemas de gran tamaño, pueden ser usados como sistemas de suministro de energía para receptores móviles. Por otro lado, las tecnologías ICET mejoran la seguridad de los usuarios finales ya que eliminan el riesgo de electrocución, como resultado del uso de transformadores resonantes de alta frecuencia que proveen un aislamiento eléctrico. Esta característica es particularmente importante en ambientes húmedos como las piscinas, jardines y baños. Además, es una buena alternativa para la implementación residencial, en lugar de los sistemas convencionales. La implementación de sistemas ICET en áreas residenciales presenta ciertos retos. En esta tesis de doctorado, se presentan diversas soluciones a estos. En el primer capítulo, el concepto de sistemas de transmisión de energía sin contacto es explicado y se presenta una clasificación de acuerdo al nivel de potencia. En el segundo capítulo, se propone un algoritmo de control adaptativo para sistemas de transmisión de energía sin contacto totalmente controlados. Este algoritmo adaptativo opera dinámicamente con los cambios de carga, alcanzando la máxima eficiencia ante diferentes condiciones de carga. En el capítulo se describe el modelado matemático del algoritmo propuesto. En el tercer capítulo, se introduce un sistema sin contacto inductivo parcialmente controlado como alternativa a la topología totalmente controlada. Se analizan las características de esta nueva topología considerando diferentes técnicas de modulación, incluyendo la modulación de frecuencia, la modulación de fase y la modulación Quantum. Luego, se evalúa el desempeño de esta nueva topología y de identifica la técnica de modulación más adecuada. Finalmente, se presenta el diseño de la nueva topología con la técnica de modulación seleccionada. En el cuarto capítulo se presenta el análisis, diseño e implementación de una técnica simple y efectiva en términos de costo para el suministro energía inalámbrica residencial con múltiples cargas móviles. La topología se basa en una conexión en cascada de un convertidor buck de lazo cerrado y de un inversor resonante de alta frecuencia operando en lazo abierto, que es cargado con varios rectificadores pasivos. El sistema propuesto incluye un transformador sliding para abastecer las cargas móviles, lo que permite una ubicación flexible y segura de las mismas. El análisis teórico y el diseño del sistema propuesto se basan en modelos matemáticos derivados del uso de la aproximación del primer armónico. Se incluyen resultados experimentales para verificar las características del sistema. Finalmente, se presentan las conclusiones más importantes de los resultados obtenido

    Robust and fast sliding-mode control for a DC-DC current-source parallel-resonant converter

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    Modern DC-DC resonant converters are normally built around a voltage-source series-resonant converter. This study aims to facilitate the practical use of current-source parallel-resonant converters due to their outstanding properties. To this end, this study presents a sliding-mode control scheme, which provides the following features to the closed-loop system: (i) high robustness to external disturbances and parameter variations and (ii) fast transient response during large and abrupt load changes. In addition, a design procedure for determining the values of the control parameters is presented. The theoretical contributions of this study are experimentally validated by selected tests on a laboratory prototype.Peer ReviewedPreprin

    Frequency-modulation control of a DC/DC current-source parallel-resonant converter

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    This paper proposes a frequency-modulation control scheme for a dc/dc current-source parallel-resonant converter with two possible configurations. The basic configuration comprises an external voltage loop, an internal current loop, and a frequency modulator: the voltage loop is responsible for regulating the output voltage, the current loop makes the system controllable and limits the input current, and the modulator provides robustness against variations in resonant component values. The enhanced configuration introduces the output inductor current as a feed-forward term and clearly improves the transient response to fast load changes. The theoretical design of these control schemes is performed systematically by first deriving their small-signal models and second using Bode diagram analysis. The actual performance of the proposed control schemes is experimentally validated by testing on a laboratory prototype.Peer ReviewedPostprint (author's final draft

    Analysis, design and implementation of a residential inductive contactless energy transfer system with multiple mobile clamps

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    This study presents the analysis, design and implementation of a simple and cost-effective residential inductive contactless energy transfer system with multiple mobile clamps. The topology is based on the cascaded connection of a buck converter and a high-frequency resonant inverter loaded by several output passive rectifiers. The proposed system includes a sliding transformer to supply the mobile loads, leading to a safe and flexible location of loads. The theoretical analysis and design of the proposed system is based on a mathematical model derived using the first harmonic approximation. Selected experimental results are included to verify the system features. In comparison with conventional topology, the proposed system significantly improves efficiency, complexity and cost.Peer ReviewedPostprint (author's final draft

    Global, regional, and national burden of colorectal cancer and its risk factors, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019

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    Funding: F Carvalho and E Fernandes acknowledge support from Fundação para a Ciência e a Tecnologia, I.P. (FCT), in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy i4HB; FCT/MCTES through the project UIDB/50006/2020. J Conde acknowledges the European Research Council Starting Grant (ERC-StG-2019-848325). V M Costa acknowledges the grant SFRH/BHD/110001/2015, received by Portuguese national funds through Fundação para a Ciência e Tecnologia (FCT), IP, under the Norma Transitória DL57/2016/CP1334/CT0006.proofepub_ahead_of_prin

    The global burden of adolescent and young adult cancer in 2019 : a systematic analysis for the Global Burden of Disease Study 2019

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    Background In estimating the global burden of cancer, adolescents and young adults with cancer are often overlooked, despite being a distinct subgroup with unique epidemiology, clinical care needs, and societal impact. Comprehensive estimates of the global cancer burden in adolescents and young adults (aged 15-39 years) are lacking. To address this gap, we analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, with a focus on the outcome of disability-adjusted life-years (DALYs), to inform global cancer control measures in adolescents and young adults. Methods Using the GBD 2019 methodology, international mortality data were collected from vital registration systems, verbal autopsies, and population-based cancer registry inputs modelled with mortality-to-incidence ratios (MIRs). Incidence was computed with mortality estimates and corresponding MIRs. Prevalence estimates were calculated using modelled survival and multiplied by disability weights to obtain years lived with disability (YLDs). Years of life lost (YLLs) were calculated as age-specific cancer deaths multiplied by the standard life expectancy at the age of death. The main outcome was DALYs (the sum of YLLs and YLDs). Estimates were presented globally and by Socio-demographic Index (SDI) quintiles (countries ranked and divided into five equal SDI groups), and all estimates were presented with corresponding 95% uncertainty intervals (UIs). For this analysis, we used the age range of 15-39 years to define adolescents and young adults. Findings There were 1.19 million (95% UI 1.11-1.28) incident cancer cases and 396 000 (370 000-425 000) deaths due to cancer among people aged 15-39 years worldwide in 2019. The highest age-standardised incidence rates occurred in high SDI (59.6 [54.5-65.7] per 100 000 person-years) and high-middle SDI countries (53.2 [48.8-57.9] per 100 000 person-years), while the highest age-standardised mortality rates were in low-middle SDI (14.2 [12.9-15.6] per 100 000 person-years) and middle SDI (13.6 [12.6-14.8] per 100 000 person-years) countries. In 2019, adolescent and young adult cancers contributed 23.5 million (21.9-25.2) DALYs to the global burden of disease, of which 2.7% (1.9-3.6) came from YLDs and 97.3% (96.4-98.1) from YLLs. Cancer was the fourth leading cause of death and tenth leading cause of DALYs in adolescents and young adults globally. Interpretation Adolescent and young adult cancers contributed substantially to the overall adolescent and young adult disease burden globally in 2019. These results provide new insights into the distribution and magnitude of the adolescent and young adult cancer burden around the world. With notable differences observed across SDI settings, these estimates can inform global and country-level cancer control efforts. Copyright (C) 2021 The Author(s). Published by Elsevier Ltd.Peer reviewe

    Cancer Incidence, Mortality, Years of Life Lost, Years Lived With Disability, and Disability-Adjusted Life Years for 29 Cancer Groups From 2010 to 2019: A Systematic Analysis for the Global Burden of Disease Study 2019.

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    The Global Burden of Diseases, Injuries, and Risk Factors Study 2019 (GBD 2019) provided systematic estimates of incidence, morbidity, and mortality to inform local and international efforts toward reducing cancer burden. To estimate cancer burden and trends globally for 204 countries and territories and by Sociodemographic Index (SDI) quintiles from 2010 to 2019. The GBD 2019 estimation methods were used to describe cancer incidence, mortality, years lived with disability, years of life lost, and disability-adjusted life years (DALYs) in 2019 and over the past decade. Estimates are also provided by quintiles of the SDI, a composite measure of educational attainment, income per capita, and total fertility rate for those younger than 25 years. Estimates include 95% uncertainty intervals (UIs). In 2019, there were an estimated 23.6 million (95% UI, 22.2-24.9 million) new cancer cases (17.2 million when excluding nonmelanoma skin cancer) and 10.0 million (95% UI, 9.36-10.6 million) cancer deaths globally, with an estimated 250 million (235-264 million) DALYs due to cancer. Since 2010, these represented a 26.3% (95% UI, 20.3%-32.3%) increase in new cases, a 20.9% (95% UI, 14.2%-27.6%) increase in deaths, and a 16.0% (95% UI, 9.3%-22.8%) increase in DALYs. Among 22 groups of diseases and injuries in the GBD 2019 study, cancer was second only to cardiovascular diseases for the number of deaths, years of life lost, and DALYs globally in 2019. Cancer burden differed across SDI quintiles. The proportion of years lived with disability that contributed to DALYs increased with SDI, ranging from 1.4% (1.1%-1.8%) in the low SDI quintile to 5.7% (4.2%-7.1%) in the high SDI quintile. While the high SDI quintile had the highest number of new cases in 2019, the middle SDI quintile had the highest number of cancer deaths and DALYs. From 2010 to 2019, the largest percentage increase in the numbers of cases and deaths occurred in the low and low-middle SDI quintiles. The results of this systematic analysis suggest that the global burden of cancer is substantial and growing, with burden differing by SDI. These results provide comprehensive and comparable estimates that can potentially inform efforts toward equitable cancer control around the world.Funding/Support: The Institute for Health Metrics and Evaluation received funding from the Bill & Melinda Gates Foundation and the American Lebanese Syrian Associated Charities. Dr Aljunid acknowledges the Department of Health Policy and Management of Kuwait University and the International Centre for Casemix and Clinical Coding, National University of Malaysia for the approval and support to participate in this research project. Dr Bhaskar acknowledges institutional support from the NSW Ministry of Health and NSW Health Pathology. Dr Bärnighausen was supported by the Alexander von Humboldt Foundation through the Alexander von Humboldt Professor award, which is funded by the German Federal Ministry of Education and Research. Dr Braithwaite acknowledges funding from the National Institutes of Health/ National Cancer Institute. Dr Conde acknowledges financial support from the European Research Council ERC Starting Grant agreement No 848325. Dr Costa acknowledges her grant (SFRH/BHD/110001/2015), received by Portuguese national funds through Fundação para a Ciência e Tecnologia, IP under the Norma Transitória grant DL57/2016/CP1334/CT0006. Dr Ghith acknowledges support from a grant from Novo Nordisk Foundation (NNF16OC0021856). Dr Glasbey is supported by a National Institute of Health Research Doctoral Research Fellowship. Dr Vivek Kumar Gupta acknowledges funding support from National Health and Medical Research Council Australia. Dr Haque thanks Jazan University, Saudi Arabia for providing access to the Saudi Digital Library for this research study. Drs Herteliu, Pana, and Ausloos are partially supported by a grant of the Romanian National Authority for Scientific Research and Innovation, CNDS-UEFISCDI, project number PN-III-P4-ID-PCCF-2016-0084. Dr Hugo received support from the Higher Education Improvement Coordination of the Brazilian Ministry of Education for a sabbatical period at the Institute for Health Metrics and Evaluation, between September 2019 and August 2020. Dr Sheikh Mohammed Shariful Islam acknowledges funding by a National Heart Foundation of Australia Fellowship and National Health and Medical Research Council Emerging Leadership Fellowship. Dr Jakovljevic acknowledges support through grant OI 175014 of the Ministry of Education Science and Technological Development of the Republic of Serbia. Dr Katikireddi acknowledges funding from a NHS Research Scotland Senior Clinical Fellowship (SCAF/15/02), the Medical Research Council (MC_UU_00022/2), and the Scottish Government Chief Scientist Office (SPHSU17). Dr Md Nuruzzaman Khan acknowledges the support of Jatiya Kabi Kazi Nazrul Islam University, Bangladesh. Dr Yun Jin Kim was supported by the Research Management Centre, Xiamen University Malaysia (XMUMRF/2020-C6/ITCM/0004). Dr Koulmane Laxminarayana acknowledges institutional support from Manipal Academy of Higher Education. Dr Landires is a member of the Sistema Nacional de Investigación, which is supported by Panama’s Secretaría Nacional de Ciencia, Tecnología e Innovación. Dr Loureiro was supported by national funds through Fundação para a Ciência e Tecnologia under the Scientific Employment Stimulus–Institutional Call (CEECINST/00049/2018). Dr Molokhia is supported by the National Institute for Health Research Biomedical Research Center at Guy’s and St Thomas’ National Health Service Foundation Trust and King’s College London. Dr Moosavi appreciates NIGEB's support. Dr Pati acknowledges support from the SIAN Institute, Association for Biodiversity Conservation & Research. Dr Rakovac acknowledges a grant from the government of the Russian Federation in the context of World Health Organization Noncommunicable Diseases Office. Dr Samy was supported by a fellowship from the Egyptian Fulbright Mission Program. Dr Sheikh acknowledges support from Health Data Research UK. Drs Adithi Shetty and Unnikrishnan acknowledge support given by Kasturba Medical College, Mangalore, Manipal Academy of Higher Education. Dr Pavanchand H. Shetty acknowledges Manipal Academy of Higher Education for their research support. Dr Diego Augusto Santos Silva was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil Finance Code 001 and is supported in part by CNPq (302028/2018-8). Dr Zhu acknowledges the Cancer Prevention and Research Institute of Texas grant RP210042

    Global, regional, and national progress towards Sustainable Development Goal 3.2 for neonatal and child health: all-cause and cause-specific mortality findings from the Global Burden of Disease Study 2019

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    Background Sustainable Development Goal 3.2 has targeted elimination of preventable child mortality, reduction of neonatal death to less than 12 per 1000 livebirths, and reduction of death of children younger than 5 years to less than 25 per 1000 livebirths, for each country by 2030. To understand current rates, recent trends, and potential trajectories of child mortality for the next decade, we present the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 findings for all-cause mortality and cause-specific mortality in children younger than 5 years of age, with multiple scenarios for child mortality in 2030 that include the consideration of potential effects of COVID-19, and a novel framework for quantifying optimal child survival. Methods We completed all-cause mortality and cause-specific mortality analyses from 204 countries and territories for detailed age groups separately, with aggregated mortality probabilities per 1000 livebirths computed for neonatal mortality rate (NMR) and under-5 mortality rate (USMR). Scenarios for 2030 represent different potential trajectories, notably including potential effects of the COVID-19 pandemic and the potential impact of improvements preferentially targeting neonatal survival. Optimal child survival metrics were developed by age, sex, and cause of death across all GBD location-years. The first metric is a global optimum and is based on the lowest observed mortality, and the second is a survival potential frontier that is based on stochastic frontier analysis of observed mortality and Healthcare Access and Quality Index. Findings Global U5MR decreased from 71.2 deaths per 1000 livebirths (95% uncertainty interval WI] 68.3-74-0) in 2000 to 37.1 (33.2-41.7) in 2019 while global NMR correspondingly declined more slowly from 28.0 deaths per 1000 live births (26.8-29-5) in 2000 to 17.9 (16.3-19-8) in 2019. In 2019,136 (67%) of 204 countries had a USMR at or below the SDG 3.2 threshold and 133 (65%) had an NMR at or below the SDG 3.2 threshold, and the reference scenario suggests that by 2030,154 (75%) of all countries could meet the U5MR targets, and 139 (68%) could meet the NMR targets. Deaths of children younger than 5 years totalled 9.65 million (95% UI 9.05-10.30) in 2000 and 5.05 million (4.27-6.02) in 2019, with the neonatal fraction of these deaths increasing from 39% (3.76 million 95% UI 3.53-4.021) in 2000 to 48% (2.42 million; 2.06-2.86) in 2019. NMR and U5MR were generally higher in males than in females, although there was no statistically significant difference at the global level. Neonatal disorders remained the leading cause of death in children younger than 5 years in 2019, followed by lower respiratory infections, diarrhoeal diseases, congenital birth defects, and malaria. The global optimum analysis suggests NMR could be reduced to as low as 0.80 (95% UI 0.71-0.86) deaths per 1000 livebirths and U5MR to 1.44 (95% UI 1-27-1.58) deaths per 1000 livebirths, and in 2019, there were as many as 1.87 million (95% UI 1-35-2.58; 37% 95% UI 32-43]) of 5.05 million more deaths of children younger than 5 years than the survival potential frontier. Interpretation Global child mortality declined by almost half between 2000 and 2019, but progress remains slower in neonates and 65 (32%) of 204 countries, mostly in sub-Saharan Africa and south Asia, are not on track to meet either SDG 3.2 target by 2030. Focused improvements in perinatal and newborn care, continued and expanded delivery of essential interventions such as vaccination and infection prevention, an enhanced focus on equity, continued focus on poverty reduction and education, and investment in strengthening health systems across the development spectrum have the potential to substantially improve USMR. Given the widespread effects of COVID-19, considerable effort will be required to maintain and accelerate progress. Copyright (C) 2021 The Author(s). Published by Elsevier Ltd
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