Browsing by Author "Harish Kumar"

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An Analytical Study on the Efficacy of Blockchain Frameworks for Student Grievance Management
(Springer, 2024) Harish Kumar; Rajesh Kumar Kaushal; Naveen Kumar; Anshul Verma
Student grievance redressal is an essential indicator of institutional effectiveness and education quality, that ensures a conducive academic environment. Every educational institute provides a 24 × 7 web or mobile platform for students to register their grievances. However, these centralized solutions often lack transparency, exhibit potential biases, and also raise security and privacy concerns that lead to student reluctance to use them. A blockchain-based grievance redressal system can address these issues by providing transparency, immutability, privacy, accountability, and auditability. However, selecting the most suitable blockchain framework is challenging and a tedious task. So, we analyzed the existing studies on performance analysis of blockchain frameworks and existing studies on grievance redressal. The finding from the reviewed studies indicates that 81% of the studies diverged towards Hyperledger fabric and Hyperledger fabric outperforms other frameworks in performance based on key parameters such as transactional throughput and latency. The consensus mechanism selection also significantly impacts the performance of a blockchain framework. RAFT is more efficient than the Kafka and solo consensus mechanism for Hyperledger fabric, in both low and high transaction volumes for read and write operations at various transfer rates. Hyperledger fabric achieves a 94.6% success rate in multiple operations with RAFT consensus as compared to 72.7% with Kafka. The success rate of Hyperledger fabric is reached to 96%, 98.4%, and 96.6% at 25tps, 50tps, and 100tps respectively for write operations whereas during the read operations, it is reached to 99.6. It is also found that the success rate is increased to 99.12% in dual channel network for write operation at varying transfer rates. This study suggests that Hyperledger Fabric is more effective for implementing a blockchain-based student grievance redressal system. © The Author(s), under exclusive licence to Springer Nature Singapore Pte Ltd. 2024.
Chronic pancreatitis. A prospective nationwide study of 1,086 subjects from India
(E.S. Burioni Ricerche Bibliografiche, 2008) Vallath Balakrishnan; Ambika Gopalakrishnan Unnikrishnan; Varghese Thomas; Gourdas Choudhuri; Peda Veeraraju; Shivram Prasad Singh; Pramod Garg; Cannore Ganesh Pai; Raveendranathan Nair Sobhana Devi; Deepak Bhasin; Venkataraman Jayanthi; Narayanan Premalatha; Ashok Chacko; Premashish Kar; Ramesh Roop Rai; Ramesh Rajan; Narayanan Subhalal; Rajiv Mehta; Sri Prakash Mishra; Manisha Dwivedi; Kattoor Ramakrishnan Nair Vinayakumar; Ashok Kumar Jain; Kalidas Biswas; Sunil Mathai; Jaison Varghese; Hariharan Ramesh; Thomas Alexander; Jacob Philip; Vigna Venugopal Raj; Ankarath Vinodkumar; Srikanth Mukevar; Prabha Sawant; Prem Nair; Harish Kumar; Surendran Sudhindran; Puneet Dhar; Othayil Vayoth Sudheer; Karimassery Ramaiyer Sundaram; Bailuru Vishwanath Tantri; Devinder Singh; Thekkayil Rajindra Nath
Context: Chronic pancreatitis is common in India. However, its risk factors are not clear. There is sparse data on the current prevalence of tropical pancreatitis in India. Objective: To undertake a prospective nationwide study of the risk factors and clinical profile of chronic pancreatitis. Setting: Thirty-two major centers from different regions of India contributed data on 1,086 patients to a common online website (www.ipans.org). Main outcome measures: Risk factors, clinical features complications and treatment of chronic pancreatitis. Results: Of the 1,086 subjects, complete data on risk factors were available for 1,033 subjects. Idiopathic pancreatitis was the most common form of pancreatitis (n=622; 60.2%) and alcoholic chronic pancreatitis accounted for about a third of the cases (n=400; 38.7%); the rest (n=11; 1.1%) had rare risk factors. Smoking and cassava intake were documented in 292 (28.3%) and 189 (18.3%) subjects, respectively. Using well-defined criteria, only 39 (3.8%)cases could be labeled as 'tropical pancreatitis'. Pain occurred in 971 patients (94.0%). Four hundred and eighteen (40.5%) subjects had diabetes mellitus. Of alcohol consumers, alcoholism and female gender were independent risk factors for diabetes in subjects with chronic pancreatitis (OR=1.48, P=0.003; and OR=1.75, P<0.001, respectively). The most common complications were pseudocysts (15.8%) and biliary obstruction (8.2%). Pancreatic cancer occurred in 42 subjects (4.1%). Ultrasound detected calculi in 69.7%, ductal dilatation in 63.4% and atrophy in 27.3%. The majority of patients were on medical therapy (n=849; 82.2%); endotherapy and surgery accounted for the rest. About 50% percent of the patients with diabetes required insulin (198/418). Conclusions: In this first nationwide prospective survey of chronic pancreatitis in India, idiopathic pancreatitis was the most common form, followed by alcoholic pancreatitis. The classical form of tropical chronic pancreatitis is becoming less common.
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
(Elsevier B.V., 2024) Austin E. Schumacher; Hmwe Hmwe Kyu; Amirali Aali; Cristiana Abbafati; Jaffar Abbas; Rouzbeh Abbasgholizadeh; Madineh Akram Abbasi; Mohammadreza Abbasian; Samar Abd ElHafeez; Michael Abdelmasseh; Sherief Abd-Elsalam; Ahmed Abdelwahab; Mohammad Abdollahi; Meriem Abdoun; Auwal Abdullahi; Ame Mehadi Abdurehman; Mesfin Abebe; Aidin Abedi; Armita Abedi; Tadesse M. Abegaz; Roberto Ariel Abeldaño Zuñiga; E.S. Abhilash; Olugbenga Olusola Abiodun; Richard Gyan Aboagye; Hassan Abolhassani; Mohamed Abouzid; Lucas Guimarães Abreu; Woldu Aberhe Abrha; Michael R.M. Abrigo; Dariush Abtahi; Samir Abu Rumeileh; Niveen M.E. Abu-Rmeileh; Salahdein Aburuz; Ahmed Abu-Zaid; Juan Manuel Acuna; Tim Adair; Isaac Yeboah Addo; Oladimeji M. Adebayo; Oyelola A. Adegboye; Victor Adekanmbi; Bashir Aden; Abiola Victor Adepoju; Charles Oluwaseun Adetunji; Temitayo Esther Adeyeoluwa; Olorunsola Israel Adeyomoye; Rishan Adha; Amin Adibi; Wirawan Adikusuma; Qorinah Estiningtyas Sakilah Adnani; Saryia Adra; Abel Afework; Aanuoluwapo Adeyimika Afolabi; Ali Afraz; Shadi Afyouni; Saira Afzal; Pradyumna Agasthi; Shahin Aghamiri; Antonella Agodi; Williams Agyemang-Duah; Bright Opoku Ahinkorah; Aqeel Ahmad; Danish Ahmad; Firdos Ahmad; Muayyad M. Ahmad; Tauseef Ahmad; Keivan Ahmadi; Amir Mahmoud Ahmadzade; Mohadese Ahmadzade; Ayman Ahmed; Haroon Ahmed; Luai A. Ahmed; Muktar Beshir Ahmed; Syed Anees Ahmed; Marjan Ajami; Budi Aji; Olufemi Ajumobi; Gizachew Taddesse Akalu; Essona Matatom Akara; Karolina Akinosoglou; Sreelatha Akkala; Samuel Akyirem; Hanadi Al Hamad; Syed Mahfuz Al Hasan; Ammar Al Homsi; Mohammad Al Qadire; Moein Ala; Timothy Olukunle Aladelusi; Tareq Mohammed Ali Al-Ahdal; Samer O. Alalalmeh; Ziyad Al-Aly; Khurshid Alam; Manjurul Alam; Zufishan Alam; Rasmieh Mustafa Al-Amer; Fahad Mashhour Alanezi; Turki M. Alanzi; Mohammed Albashtawy; Mohammad T. AlBataineh; Robert W. Aldridge; Sharifullah Alemi; Ayman Al-Eyadhy; Adel Ali Saeed Al-Gheethi; Khalid F. Alhabib; Fadwa Alhalaiqa Naji Alhalaiqa; Mohammed Khaled Al-Hanawi; Abid Ali; Akhtar Ali; Beriwan Abdulqadir Ali; Hassam Ali; Mohammed Usman Ali; Rafat Ali; Syed Shujait Shujait Ali; Zahid Ali; Shohreh Alian Samakkhah; Gianfranco Alicandro; Sheikh Mohammad Alif; Mohammad Aligol; Rasoul Alimi; Ahmednur Adem Aliyi; Adel Al-Jumaily; Syed Mohamed Aljunid; Wael Almahmeed; Sabah Al-Marwani; Sadeq Ali Ali Al-Maweri; Joseph Uy Almazan; Hesham M. Al-Mekhlafi; Omar Almidani; Mahmoud A. Alomari; Nivaldo Alonso; Jaber S. Alqahtani; Ahmed Yaseen Alqutaibi; Salman Khalifah Al-Sabah; Awais Altaf; Jaffar A. Al-Tawfiq; Khalid A. Altirkawi; Farrukh Jawad Alvi; Hassan Alwafi; Yaser Mohammed Al-Worafi; Hany Aly; Karem H. Alzoubi; Azmeraw T. Amare; Edward Kwabena Ameyaw; Abebe Feyissa Amhare; Tarek Tawfik Amin; Alireza Amindarolzarbi; Javad Aminian Dehkordi; Sohrab Amiri; Hubert Amu; Dickson A. Amugsi; Jimoh Amzat; Robert Ancuceanu; Deanna Anderlini; Pedro Prata Andrade; Catalina Liliana Andrei; Tudorel Andrei; Dhanalakshmi Angappan; Abhishek Anil; Afifa Anjum; Catherine M. Antony; Ernoiz Antriyandarti; Iyadunni Adesola Anuoluwa; Sumadi Lukman Anwar; Anayochukwu Edward Anyasodor; Seth Christopher Yaw Appiah; Muhammad Aqeel; Jalal Arabloo; Razman Arabzadeh Bahri; Morteza Arab-Zozani; Mosab Arafat; Ana Margarida Araújo; Aleksandr Y. Aravkin; Abdulfatai Aremu; Hany Ariffin; Timur Aripov; Benedetta Armocida; Mahwish Arooj; Anton A. Artamonov; Kurnia Dwi Artanti; Judie Arulappan; Idowu Thomas Aruleba; Raphael Taiwo Aruleba; Ashokan Arumugam; Malke Asaad; Saeed Asgary; Mubarek Yesse Ashemo; Muhammad Ashraf; Marvellous O. Asika; Seyyed Shamsadin Athari; Maha Moh'd Wahbi Atout; Alok Atreya; Sameh Attia; Avinash Aujayeb; Abolfazl Avan; Adedapo Wasiu Awotidebe; Beatriz Paulina Ayala Quintanilla; Martin Amogre Ayanore; Getnet Melaku Ayele; Jose L. Ayuso-Mateos; Seyed Mohammad Ayyoubzadeh; Sina Azadnajafabad; Gulrez Shah Azhar; Shahkaar Aziz; Ahmed Y. Azzam; Mina Babashahi; Abraham Samuel Babu; Muhammad Badar; Alaa Badawi; Ashish D. Badiye; Soroush Baghdadi; Nasser Bagheri; Sara Bagherieh; Sulaiman Bah; Saeed Bahadorikhalili; Jianjun Bai; Ruhai Bai; Jennifer L. Baker; Shankar M. Bakkannavar; Abdulaziz T. Bako; Senthilkumar Balakrishnan; Saliu A. Balogun; Ovidiu Constantin Baltatu; Kiran Bam; Maciej Banach; Soham Bandyopadhyay; Biswajit Banik; Palash Chandra Banik; Hansi Bansal; Shirin Barati; Martina Barchitta; Mainak Bardhan; Suzanne Lyn Barker-Collo; Francesco Barone-Adesi; Hiba Jawdat Barqawi; Ronald D. Barr; Lope H. Barrero; Zarrin Basharat; Asma'u I.J. Bashir; Hameed Akande Bashiru; Pritish Baskaran; Buddha Basnyat; Quique Bassat; João Diogo Basso; Saurav Basu; Kavita Batra; Ravi Batra; Bernhard T. Baune; Mohsen Bayati; Nebiyou Simegnew Bayileyegn; Thomas Beaney; Neeraj Bedi; Tahmina Begum; Emad Behboudi; Amir Hossein Behnoush; Maryam Beiranvand; Diana Fernanda Bejarano Ramirez; Uzma Iqbal Belgaumi; Michelle L. Bell; Aminu K. Bello; Muhammad Bashir Bello; Olorunjuwon Omolaja Bello; Luis Belo; Apostolos Beloukas; Salaheddine Bendak; Derrick A. Bennett; Isabela M. Bensenor; Habib Benzian; Zombor Berezvai; Adam E. Berman; Amiel Nazer C. Bermudez; Paulo J.G. Bettencourt; Habtamu B. Beyene; Kebede A. Beyene; Devidas S. Bhagat; Akshaya Srikanth Bhagavathula; Neeraj Bhala; Ashish Bhalla; Dinesh Bhandari; Nikha Bhardwaj; Pankaj Bhardwaj; Prarthna V. Bhardwaj; Ashish Bhargava; Sonu Bhaskar; Vivek Bhat; Gurjit Kaur Bhatti; Jasvinder Singh Bhatti; Manpreet S. Bhatti; Rajbir Bhatti; Zulfiqar A. Bhutta; Boris Bikbov; Nada Binmadi; Bagas Suryo Bintoro; Antonio Biondi; Catherine Bisignano; Francesca Bisulli; Atanu Biswas; Raaj Kishore Biswas; Saeid Bitaraf; Tone Bjørge; Archie Bleyer; Mary Sefa Boampong; Virginia Bodolica; Aadam Olalekan Bodunrin; Obasanjo Afolabi Bolarinwa; Milad Bonakdar Hashemi; Aime Bonny; Kaustubh Bora; Berrak Bora Basara; Safiya Bala Borodo; Rohan Borschmann; Alejandro Botero Carvajal; Souad Bouaoud; Sofiane Boudalia; Edward J. Boyko; Nicola Luigi Bragazzi; Dejana Braithwaite; Hermann Brenner; Gabrielle Britton; Annie J. Browne; Andre R. Brunoni; Norma B. Bulamu; Lemma N. Bulto; Danilo Buonsenso; Katrin Burkart; Richard A. Burns; Sharath Burugina Nagaraja; Reinhard Busse; Yasser Bustanji; Zahid A. Butt; Florentino Luciano Caetano Dos Santos; Tianji Cai; Daniela Calina; Luis Alberto Cámera; Luciana Aparecida Campos; Ismael R. Campos-Nonato; Chao Cao; Carlos Alberto Cardenas; Rosario Cárdenas; Sinclair Carr; Giulia Carreras; Juan J. Carrero; Andrea Carugno; Felix Carvalho; Márcia Carvalho; Joao Mauricio Castaldelli-Maia; Carlos A. Castañeda-Orjuela; Giulio Castelpietra; Ferrán Catalá-López; Alberico L. Catapano; Maria Sofia Cattaruzza; Arthur Caye; Christopher R. Cederroth; Francieli Cembranel; Muthia Cenderadewi; Kelly M. Cercy; Ester Cerin; Muge Cevik; Pamela R. Chacón-Uscamaita; Yaacoub Chahine; Chiranjib Chakraborty; Jeffrey Shi Kai Chan; Chin-Kuo Chang; Periklis Charalampous; Jaykaran Charan; Vijay Kumar Chattu; Victoria Chatzimavridou-Grigoriadou; Malizgani Paul Chavula; Huzaifa Ahmad Cheema; An-Tian Chen; Haowei Chen; Lingxiao Chen; Meng Xuan Chen; Simiao Chen; Nicolas Cherbuin; Derek S. Chew; Gerald Chi; Jesus Lorenzo Chirinos-Caceres; Abdulaal Chitheer; So Mi Jemma Cho; William C.S. Cho; Bryan Chong; Hitesh Chopra; Rahul Choudhary; Rajiv Chowdhury; Dinh-Toi Chu; Isaac Sunday Chukwu; Eric Chung; Eunice Chung; Sheng-Chia Chung; Karly I. Cini; Cain C.T. Clark; Kaleb Coberly; Alyssa Columbus; Haley Comfort; Joao Conde; Sara Conti; Paolo Angelo Cortesi; Vera Marisa Costa; Ewerton Cousin; Richard G. Cowden; Michael H. Criqui; Natália Cruz-Martins; Garland T. Culbreth; Patricia Cullen; Matthew Cunningham; Daniel da Silva E Silva; Sriharsha Dadana; Omid Dadras; Zhaoli Dai; Koustuv Dalal; Lachlan L. Dalli; Giovanni Damiani; Emanuele D'Amico; Sara Daneshvar; Aso Mohammad Darwesh; Jai K. Das; Saswati Das; Nihar Ranjan Dash; Mohsen Dashti; Claudio Alberto Dávila-Cervantes; Nicole Davis Weaver; Kairat Davletov; Diego De Leo; Aklilu Tamire Debele; Louisa Degenhardt; Reza Dehbandi; Lee Deitesfeld; Ivan Delgado-Enciso; Laura Delgado-Ortiz; Daniel Demant; Berecha Hundessa Demessa; Andreas K. Demetriades; Xinlei Deng; Edgar Denova-Gutiérrez; Kebede Deribe; Nikolaos Dervenis; Don C. Des Jarlais; Hardik Dineshbhai Desai; Rupak Desai; Keshab Deuba; Vinoth Gnana Chellaiyan Devanbu; Sourav Dey; Arkadeep Dhali; Kuldeep Dhama; Mandira Lamichhane Dhimal; Meghnath Dhimal; Sameer Dhingra; Diana Dias Da Silva; Daniel Diaz; Adriana Dima; Delaney D. Ding; M. Ashworth Dirac; Abhinav Dixit; Shilpi Gupta Dixit; Thanh Chi Do; Thao Huynh Phuong Do; Camila Bruneli Do Prado; Masoud Dodangeh; Klara Georgieva Dokova; Christiane Dolecek; E Ray Dorsey; Wendel Mombaque dos Santos; Rajkumar Doshi; Leila Doshmangir; Abdel Douiri; Robert Kokou Dowou; Tim Robert Driscoll; Haneil Larson Dsouza; John Dube; Samuel C. Dumith; Susanna J. Dunachie; Bruce B. Duncan; Andre Rodrigues Duraes; Senbagam Duraisamy; Oyewole Christopher Durojaiye; Sulagna Dutta; Paulina Agnieszka Dzianach; Arkadiusz Marian Dziedzic; Oluwakemi Ebenezer; Ejemai Eboreime; Alireza Ebrahimi; Chidiebere Peter Echieh; Abdelaziz Ed-Dra; Hisham Atan Edinur; David Edvardsson; Kristina Edvardsson; Defi Efendi; Ferry Efendi; Shayan Eghdami; Terje Andreas Eikemo; Ebrahim Eini; Michael Ekholuenetale; Emmanuel Ekpor; Temitope Cyrus Ekundayo; Rabie Adel El Arab; Doaa Abdel Wahab El Morsi; Maysaa El Sayed Zaki; Maha El Tantawi; Iffat Elbarazi; Noha Mousaad Elemam; Frank J. Elgar; Islam Y. Elgendy; Ghada Metwally Tawfik ElGohary; Hala Rashad Elhabashy; Muhammed Elhadi; Omar Abdelsadek Abdou Elmeligy; Mohammed Elshaer; Ibrahim Elsohaby; Amir Emami Zeydi; Mehdi Emamverdi; Theophilus I. Emeto; Luchuo Engelbert Bain; Ryenchindorj Erkhembayar; Tesfahun C. Eshetie; Sharareh Eskandarieh; Juan Espinosa-Montero; Kara Estep; Farshid Etaee; Ugochukwu Anthony Eze; Natalia Fabin; Adewale Oluwaseun Fadaka; Adeniyi Francis Fagbamigbe; Saman Fahimi; Luca Falzone; Carla Sofia E Sá Farinha; MoezAlIslam Ezzat Mahmoud Faris; Mohsen Farjoud Kouhanjani; Andre Faro; Hossein Farrokhpour; Ali Fatehizadeh; Hamed Fattahi; Nelsensius Klau Fauk; Pooria Fazeli; Valery L. Feigin; Ginenus Fekadu; Seyed-Mohammad Fereshtehnejad; Abdullah Hamid Feroze; Daniela Ferrante; Pietro Ferrara; Nuno Ferreira; Getahun Fetensa; Irina Filip; Florian Fischer; Joanne Flavel; Abraham D. Flaxman; Luisa S. Flor; Bobirca Teodor Florin; Morenike Oluwatoyin Folayan; Kristen Marie Foley; Artem Alekseevich Fomenkov; Lisa M. Force; Carla Fornari; Behzad Foroutan; Matteo Foschi; Kate Louise Francis; Richard Charles Franklin; Alberto Freitas; Joseph Friedman; Sara D. Friedman; Takeshi Fukumoto; John E. Fuller; Peter Andras Gaal; Muktar A. Gadanya; Santosh Gaihre; Abduzhappar Gaipov; Emmanuela Gakidou; Yaseen Galali; Nasrin Galehdar; Silvano Gallus; Quan Gan; Aravind P. Gandhi; Balasankar Ganesan; Jalaj Garg; Shuo-Yan Gau; Prem Gautam; Rupesh K. Gautam; Federica Gazzelloni; Miglas W. Gebregergis; Mesfin Gebrehiwot; Tesfay Brhane Gebremariam; Urge Gerema; Motuma Erena Getachew; Tamirat Getachew; Peter W. Gething; Mansour Ghafourifard; Sulmaz Ghahramani; Khalid Yaser Ghailan; Alireza Ghajar; Mohammad Javad Ghanbarnia; MohammadReza Ghasemi; Afsaneh Ghasemzadeh; Fariba Ghassemi; Ramy Mohamed Ghazy; Sailaja Ghimire; Asadollah Gholamian; Ali Gholamrezanezhad; Pooyan Ghorbani Vajargah; Ghozali Ghozali; Sherief Ghozy; Arun Digambarrao Ghuge; Alessandro Gialluisi; Ruth Margaret Gibson; Artyom Urievich Gil; Paramjit Singh Gill; Tiffany K. Gill; Richard F. Gillum; Themba G. Ginindza; Alem Girmay; James C. Glasbey; Elena V. Gnedovskaya; Laszlo Göbölös; Amit Goel; Mohamad Goldust; Mahaveer Golechha; Pouya Goleij; Arefeh Golestanfar; Davide Golinelli; Philimon N. Gona; Houman Goudarzi; Amir Hossein Goudarzian; Anmol Goyal; Scott Greenhalgh; Michal Grivna; Giovanni Guarducci; Mohammed Ibrahim Mohialdeen Gubari; Mesay Dechasa Gudeta; Avirup Guha; Stefano Guicciardi; Damitha Asanga Gunawardane; Sasidhar Gunturu; Cui Guo; Anish Kumar Gupta; Bhawna Gupta; Indarchand Ratanlal Gupta; Rajat Das Gupta; Sapna Gupta; Veer Bala Gupta; Vijai Kumar Gupta; Vivek Kumar Gupta; Reyna Alma Gutiérrez; Farrokh Habibzadeh; Parham Habibzadeh; Vladimir Hachinski; Mohammad Haddadi; Rasool Haddadi; Nils Haep; Adel Hajj Ali; Esam S. Halboub; Sobia Ahsan Halim; Brian J. Hall; Sebastian Haller; Rabih Halwani; Randah R. Hamadeh; Kanaan Hamagharib Abdullah; Samer Hamidi; Mohammad Hamiduzzaman; Ahmad Hammoud; Nasrin Hanifi; Graeme J. Hankey; Md Abdul Hannan; Md Nuruzzaman Haque; Harapan Harapan; Josep Maria Haro; Ahmed I. Hasaballah; Faizul Hasan; Ikramul Hasan; M Tasdik Hasan; Hamidreza Hasani; Mohammad Hasanian; Ali Hasanpour-Dehkordi; Abbas M. Hassan; Amr Hassan; Hossein Hassanian-Moghaddam; Soheil Hassanipour; Johannes Haubold; Rasmus J. Havmoeller; Simon I. Hay; Youssef Hbid; Jeffrey J. Hebert; Omar E. Hegazi; Golnaz Heidari; Mohammad Heidari; Mahsa Heidari-Foroozan; Reza Heidari-Soureshjani; Bartosz Helfer; Claudiu Herteliu; Hamed Hesami; Dineshani Hettiarachchi; Demisu Zenbaba Heyi; Kamal Hezam; Yuta Hiraike; Howard J. Hoffman; Ramesh Holla; Nobuyuki Horita; Md Belal Hossain; Md Mahbub Hossain; Sahadat Hossain; Mohammad-Salar Hosseini; Hassan Hosseinzadeh; Mehdi Hosseinzadeh; Mihaela Hostiuc; Sorin Hostiuc; Mohamed Hsairi; Vivian Chia-Rong Hsieh; Chengxi Hu; Junjie Huang; Md Nazmul Huda; Fernando N. Hugo; Michael Hultström; Javid Hussain; Salman Hussain; Nawfal R. Hussein; Le Duc Huy; Hong-Han Huynh; Bing-Fang Hwang; Segun Emmanuel Ibitoye; Oluwatope Olaniyi Idowu; Desta Ijo; Kevin S. Ikuta; Mehran Ilaghi; Olayinka Stephen Ilesanmi; Irena M. Ilic; Milena D. Ilic; Mustapha Immurana; Leeberk Raja Inbaraj; Arnaud Iradukunda; Farideh Iravanpour; Kenneth Chukwuemeka Iregbu; Md Rabiul Islam; Mohammad Mainul Islam; Sheikh Mohammed Shariful Islam; Farhad Islami; Nahlah Elkudssiah Ismail; Gaetano Isola; Masao Iwagami; Chidozie C.D. Iwu; Chinwe Juliana Iwu-Jaja; Mahalaxmi Iyer; Linda Merin; Jalil Jaafari; Louis Jacob; Kathryn H. Jacobsen; Farhad Jadidi-Niaragh; Morteza Jafarinia; Khushleen Jaggi; Kasra Jahankhani; Nader Jahanmehr; Haitham Jahrami; Akhil Jain; Nityanand Jain; Ammar Abdulrahman Jairoun; Mihajlo Jakovljevic; Reza Jalilzadeh Yengejeh; Elham Jamshidi; Chinmay T. Jani; Mark M. Janko; Abubakar Ibrahim Jatau; Sathish Kumar Jayapal; Shubha Jayaram; Jayakumar Jeganathan; Alelign Tasew Jema; Digisie Mequanint Jemere; Wonjeong Jeong; Anil K. Jha; Ravi Prakash Jha; John S. Ji; Heng Jiang; Yingzhao Jin; Yinzi Jin; Olatunji Johnson; Nabi Jomehzadeh; Darwin Phan Jones; Tamas Joo; Abel Joseph; Nitin Joseph; Charity Ehimwenma Joshua; Jacek Jerzy Jozwiak; Mikk Jürisson; Billingsley Kaambwa; Ali Kabir; Hannaneh Kabir; Zubair Kabir; Vidya Kadashetti; Farima Kahe; Pradnya Vishal Kakodkar; Rizwan Kalani; Leila R. Kalankesh; Feroze Kaliyadan; Sanjay Kalra; Ashwin Kamath; Arun Kamireddy; Thanigaivelan Kanagasabai; Himal Kandel; Edmund Wedam Kanmiki; Kehinde Kazeem Kanmodi; Rami S. Kantar; Neeti Kapoor; Mehrdad Karajizadeh; Behzad Karami Matin; Shama D. Karanth; Ibraheem M. Karaye; Asima Karim; Hanie Karimi; Salah Eddin Karimi; Arman Karimi Behnagh; Samad Karkhah; Ajit K. Karna; Faizan Zaffar Kashoo; Hengameh Kasraei; Nigussie Assefa Kassaw; Nicholas J. Kassebaum; Molly B. Kassel; Adarsh Katamreddy; Srinivasa Vittal Katikireddi; Patrick D.M.C. Katoto; Joonas H. Kauppila; Navjot Kaur; Neda Kaydi; Jeanne Françoise Kayibanda; Gbenga A. Kayode; Foad Kazemi; Sina Kazemian; Sara Kazeminia; Leila Keikavoosi-Arani; Cathleen Keller; John H. Kempen; Jessica A. Kerr; Emmanuelle Kesse-Guyot; Mohammad Keykhaei; Mohamad Mehdi Khadembashiri; Mohammad Amin Khadembashiri; Morteza Abdullatif Khafaie; Himanshu Khajuria; Mohammad Khalafi; Amirmohammad Khalaji; Nauman Khalid; Ibrahim A. Khalil; Faham Khamesipour; Asaduzzaman Khan; Gulfaraz Khan; Ikramullah Khan; Imteyaz A. Khan; Maseer Khan; Moien A.B. Khan; Taimoor Khan; Mahammed Ziauddin Khan Suheb; Shaghayegh Khanmohammadi; Khaled Khatab; Fatemeh Khatami; Armin Khavandegar; Hamid Reza Khayat Kashani; Khalid A. Kheirallah; Feriha Fatima Khidri; Elaheh Khodadoust; Moein Khormali; Mahmood Khosrowjerdi; Jagdish Khubchandani; Helda Khusun; Zemene Demelash Kifle; Grace Kim; Jihee Kim; Ruth W. Kimokoti; Kasey E. Kinzel; Girmay Tsegay Kiross; Adnan Kisa; Sezer Kisa; Juniper Boroka Kiss; Mika Kivimäki; Desmond Klu; Ann Kristin Skrindo Knudsen; Ali-Asghar Kolahi; Farzad Kompani; Gerbrand Koren; Soewarta Kosen; Karel Kostev; Ashwin Laxmikant Kotnis; Parvaiz A. Koul; Sindhura Lakshmi Koulmane Laxminarayana; Ai Koyanagi; Michael A. Kravchenko; Kewal Krishan; Hare Krishna; Vijay Krishnamoorthy; Yuvaraj Krishnamoorthy; Kris J. Krohn; Barthelemy Kuate Defo; Connor M. Kubeisy; Burcu Kucuk Bicer; Md Abdul Kuddus; Mohammed Kuddus; Ilari Kuitunen; Omar Kujan; Mukhtar Kulimbet; Vishnutheertha Kulkarni; Ashish Kumar; Harish Kumar; Nithin Kumar; Rahul Kumar; Shiv Kumar; Madhulata Kumari; Almagul Kurmanova; Om P. Kurmi; Asep Kusnali; Dian Kusuma; Tezer Kutluk; Ambily Kuttikkattu; Evans F. Kyei; Ilias Kyriopoulos; Carlo La Vecchia; Muhammad Awwal Ladan; Lucie Laflamme; Chandrakant Lahariya; Abdelilah Lahmar; Daphne Teck Ching Lai; Tri Laksono; Dharmesh Kumar Lal; Ratilal Lalloo; Tea Lallukka; Judit Lám; Demetris Lamnisos; Tuo Lan; Francesco Lanfranchi; Berthold Langguth; Van Charles Lansingh; Ariane Laplante-Lévesque; Bagher Larijani; Anders O. Larsson; Savita Lasrado; Kamaluddin Latief; Mahrukh Latif; Kaveh Latifinaibin; Paolo Lauriola; Long Khanh Dao Le; Nhi Huu Hanh Le; Thao Thi Thu Le; Trang Diep Thanh Le; Munjae Lee; Paul H. Lee; Sang-Woong Lee; Seung Won Lee; Wei-Chen Lee; Yo Han Lee; Samson Mideksa Legesse; James Leigh; Jacopo Lenzi; Elvynna Leong; Temesgen L. Lerango; Ming-Chieh Li; Wei Li; Xiaopan Li; Yichong Li; Zhihui Li; Massimo Libra; Virendra S. Ligade; Andrew Tiyamike Makhiringa Likaka; Lee-Ling Lim; Ro-Ting Lin; Shuzhi Lin; Vasileios-Arsenios Lioutas; Stefan Listl; Jue Liu; Simin Liu; Xiaofeng Liu; Katherine M. Livingstone; Erand Llanaj; Chun-Han Lo; Arianna Maever Loreche; László Lorenzovici; Mojgan Lotfi; Masoud Lotfizadeh; Rafael Lozano; Jailos Lubinda; Giancarlo Lucchetti; Alessandra Lugo; Raimundas Lunevicius
Background: Estimates 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. Methods: 22 223 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. Findings: Global 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. Interpretation: Global 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. Funding: Bill & Melinda Gates Foundation. © 2024 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license
Global fertility in 204 countries and territories, 1950–2021, with forecasts to 2100: a comprehensive demographic analysis for the Global Burden of Disease Study 2021
(Elsevier B.V., 2024) Natalia V. Bhattacharjee; Austin E. Schumacher; Amirali Aali; Yohannes Habtegiorgis Abate; Rouzbeh Abbasgholizadeh; Mohammadreza Abbasian; Mohsen Abbasi-Kangevari; Hedayat Abbastabar; Samar Abd ElHafeez; Sherief Abd-Elsalam; Mohammad Abdollahi; Mohammad-Amin Abdollahifar; Meriem Abdoun; Auwal Abdullahi; Mesfin Abebe; Samrawit Shawel Abebe; Olumide Abiodun; Hassan Abolhassani; Meysam Abolmaali; Mohamed Abouzid; Girma Beressa Aboye; Lucas Guimarães Abreu; Woldu Aberhe Abrha; Michael R.M. Abrigo; Dariush Abtahi; Hasan Abualruz; Bilyaminu Abubakar; Eman Abu-Gharbieh; Niveen M.E. Abu-Rmeileh; Tadele Girum Girum Adal; Mesafint Molla Adane; Oluwafemi Atanda Adeagbo Adeagbo; Rufus Adesoji Adedoyin; Victor Adekanmbi; Bashir Aden; Abiola Victor Adepoju; Olatunji O. Adetokunboh; Juliana Bunmi Adetunji; Daniel Adedayo Adeyinka; Olorunsola Israel Adeyomoye; Qorinah Estiningtyas Sakilah Adnani; Saryia Adra; Rotimi Felix Afolabi; Shadi Afyouni; Muhammad Sohail Afzal; Saira Afzal; Shahin Aghamiri; Antonella Agodi; Williams Agyemang-Duah; Bright Opoku Ahinkorah; Austin J. Ahlstrom; Aqeel Ahmad; Danish Ahmad; Firdos Ahmad; Muayyad M. Ahmad; Sajjad Ahmad; Tauseef Ahmad; Ali Ahmed; Ayman Ahmed; Haroon Ahmed; Luai A. Ahmed; Meqdad Saleh Ahmed; Syed Anees Ahmed; Marjan Ajami; Budi Aji; Gizachew Taddesse Akalu; Hossein Akbarialiabad; Rufus Olusola Akinyemi; Mohammed Ahmed Akkaif; Sreelatha Akkala; Hanadi Al Hamad; Syed Mahfuz Al Hasan; Mohammad Al Qadire; Tareq Mohammed Ali AL-Ahdal; Samer O. Alalalmeh; Tariq A. Alalwan; Ziyad Al-Aly; Khurshid Alam; Rasmieh Mustafa Al-Amer; Fahad Mashhour Alanezi; Turki M. Alanzi; Almaza Albakri; Mohammed Albashtawy; Mohammad T. AlBataineh; Hediyeh Alemi; Sharifullah Alemi; Yihun Mulugeta Alemu; Ayman Al-Eyadhy; Adel Ali Saeed Al-Gheethi; Khalid F. Alhabib; Noora Alhajri; Fadwa Alhalaiqa Naji Alhalaiqa; Robert Kaba Alhassan; Abid Ali; Beriwan Abdulqadir Ali; Liaqat Ali; Mohammed Usman Ali; Rafat Ali; Syed Shujait Shujait Ali; Sheikh Mohammad Alif; Mohammad Aligol; Mehran Alijanzadeh; Mohammad A.M. Aljasir; Syed Mohamed Aljunid; Sabah Al-Marwani; Joseph Uy Almazan; Hesham M. Al-Mekhlafi; Omar Almidani; Mahmoud A. Alomari; Basem Al-Omari; Jaber S. Alqahtani; Ahmed Yaseen Alqutaibi; Rajaa M. Al-Raddadi; Salman Khalifah Al-Sabah; Awais Altaf; Jaffar A. Al-Tawfiq; Khalid A. Altirkawi; Deborah Oyine Aluh; Farrukh Jawad Alvi; Nelson Alvis-Guzman; Hassan Alwafi; Yaser Mohammed Al-Worafi; Hany Aly; Safwat Aly; Karem H. Alzoubi; Edward Kwabena Ameyaw; Tarek Tawfik Amin; Alireza Amindarolzarbi; Mostafa Amini-Rarani; Sohrab Amiri; Irene Gyamfuah Ampomah; Dickson A. Amugsi; Ganiyu Adeniyi Amusa; Robert Ancuceanu; Deanna Anderlini; Pedro Prata Andrade; Catalina Liliana Andrei; Tudorel Andrei; Abhishek Anil; Sneha Anil; Adnan Ansar; Alireza Ansari-Moghaddam; Catherine M. Antony; Ernoiz Antriyandarti; Saeid Anvari; Saleha Anwar; Razique Anwer; Anayochukwu Edward Anyasodor; Jalal Arabloo; Razman Arabzadeh Bahri; Elshaimaa A. Arafa; Mosab Arafat; Ana Margarida Araujo; Aleksandr Y. Aravkin; Abdulfatai Aremu; Timur Aripov; Mesay Arkew; Benedetta Armocida; Johan Ärnlöv; Mahwish Arooj; Anton A. Artamonov; Judie Arulappan; Raphael Taiwo Aruleba; Ashokan Arumugam; Mohsen Asadi-Lari; Zatollah Asemi; Saeed Asgary; Mona Asghariahmadabad; Mohammad Asghari-Jafarabadi; Mubarek Yesse Ashemo; Muhammad Ashraf; Tahira Ashraf; Marvellous O. Asika; Seyyed Shamsadin Athari; Maha Moh'd Wahbi Atout; Alok Atreya; Avinash Aujayeb; Marcel Ausloos; Abolfazl Avan; Amlaku Mulat Aweke; Getnet Melaku Ayele; Seyed Mohammad Ayyoubzadeh; Sina Azadnajafabad; Rui M.S. Azevedo; Ahmed Y. Azzam; Muhammad Badar; Ashish D. Badiye; Soroush Baghdadi; Nasser Bagheri; Sara Bagherieh; Najmeh Bahmanziari; Ruhai Bai; Atif Amin Baig; Jennifer L. Baker; Abdulaziz T. Bako; Ravleen Kaur Bakshi; Madhan Balasubramanian; Ovidiu Constantin Baltatu; Kiran Bam; MacIej Banach; Soham Bandyopadhyay; Biswajit Banik; Palash Chandra Banik; Hansi Bansal; Mehmet Firat Baran; Martina Barchitta; Mainak Bardhan; Erfan Bardideh; Suzanne Lyn Barker-Collo; Till Winfried Bärnighausen; Francesco Barone-Adesi; Hiba Jawdat Barqawi; Amadou Barrow; Sandra Barteit; Zarrin Basharat; Asma'u I.J. Bashir; Hameed Akande Bashiru; Afisu Basiru; Joao Diogo Basso; Sanjay Basu; Abdul-Monim Mohammad Batiha; Kavita Batra; Bernhard T. Baune; Mohsen Bayati; Tahmina Begum; Emad Behboudi; Amir Hossein Behnoush; Maryam Beiranvand; Diana Fernanda Bejarano Ramirez; Alehegn Bekele; Sefealem Assefa Belay; Uzma Iqbal Belgaumi; Michelle L. Bell; Olorunjuwon Omolaja Bello; Apostolos Beloukas; Isabela M. Bensenor; Zombor Berezvai; Alemshet Yirga Berhie; Amiel Nazer C. Bermudez; Paulo J.G. Bettencourt; Akshaya Srikanth Bhagavathula; Nikha Bhardwaj; Pankaj Bhardwaj; Prarthna V. Bhardwaj; Sonu Bhaskar; Vivek Bhat; Gurjit Kaur Bhatti; Jasvinder Singh Bhatti; Manpreet S. Bhatti; Rajbir Bhatti; Antonio Biondi; Catherine Bisignano; Atanu Biswas; Raaj Kishore Biswas; Veera R. Bitra; Tone Bjørge; Elye Bliss; Micheal Kofi Boachie; Anca Vasilica Bobirca; Virginia Bodolica; Aadam Olalekan Bodunrin; Eyob Ketema Bogale; Kassawmar Angaw Bogale; Milad Bonakdar Hashemi; Berrak Bora Basara; Souad Bouaoud; Dejana Braithwaite; Michael Brauer; Nicholas J.K. Breitborde; Dana Bryazka; Norma B. Bulamu; Danilo Buonsenso; Katrin Burkart; Richard A. Burns; Yasser Bustanji; Nadeem Shafique Butt; Zahid A. Butt; Florentino Luciano Caetano Dos Santos; Daniela Calina; Ismael R. Campos-Nonato; Fan Cao; Shujin Cao; Angelo Capodici; Giulia Carreras; Andrea Carugno; Carlos A. Castañeda-Orjuela; Giulio Castelpietra; Maria Sofia Cattaruzza; Arthur Caye; Luca Cegolon; Francieli Cembranel; Ester Cerin; Joshua Chadwick; Yaacoub Chahine; Chiranjib Chakraborty; Julian Chalek; Jeffrey Shi Kai Chan; Periklis Charalampous; Vijay Kumar Chattu; Sarika Chaturvedi; Malizgani Paul Chavula; An-Tian Chen; Haowei Chen; Simiao Chen; Gerald Chi; Fatemeh Chichagi; Ju-Huei Chien; Patrick R. Ching; William C.S. Cho; Sungchul Choi; Bryan Chong; Hitesh Chopra; Sonali Gajanan Choudhari; Devasahayam J. Christopher; Dinh-Toi Chu; Isaac Sunday Chukwu; Eric Chung; Sheng-Chia Chung; Zinhle Cindi; Iolanda Cioffi; Raffaela Ciuffreda; Rafael M. Claro; Kaleb Coberly; Alyssa Columbus; Haley Comfort; Joao Conde; Michael H. Criqui; Natalia Cruz-Martins; Silvia Magali Cuadra-Hernández; Sriharsha Dadana; Omid Dadras; Tukur Dahiru; Zhaoli Dai; Bronte Dalton; Giovanni Damiani; Aso Mohammad Darwesh; Jai K. Das; Saswati Das; Mohsen Dashti; Anna Dastiridou; Claudio Alberto Dávila-Cervantes; Kairat Davletov; Aklilu Tamire Debele; Shayom Debopadhaya; Somayeh Delavari; Ivan Delgado-Enciso; Dessalegn Demeke; Berecha Hundessa Demessa; Xinlei Deng; Edgar Denova-Gutiérrez; Kebede Deribe; Nikolaos Dervenis; Hardik Dineshbhai Desai; Rupak Desai; Vinoth Gnana Chellaiyan Devanbu; Arkadeep Dhali; Kuldeep Dhama; Meghnath Dhimal; Vishal R. Dhulipala; Diana Dias Da Silva; Daniel Diaz; Michael J. Diaz; Adriana Dima; Delaney D. Ding; M. Ashworth Dirac; Thanh Chi Do; Thao Huynh Phuong Do; Camila Bruneli Do Prado; Sushil Dohare; Wanyue Dong; Mario D'Oria; Wendel Mombaque Dos Santos; Leila Doshmangir; Robert Kokou Dowou; Ashel Chelsea Dsouza; Haneil Larson Dsouza; Viola Dsouza; John Dube; Joe Duprey; Andre Rodrigues Duraes; Senbagam Duraisamy; Oyewole Christopher Durojaiye; Sulagna Dutta; Laura Dwyer-Lindgren; Paulina Agnieszka Dzianach; Arkadiusz Marian Dziedzic; Alireza Ebrahimi; Hisham Atan Edinur; Kristina Edvardsson; Ferry Efendi; Terje Andreas Eikemo; Michael Ekholuenetale; Maha El Tantawi; Noha Mousaad Elemam; Ghada Metwally Tawfik ElGohary; Muhammed Elhadi; Legesse Tesfaye Elilo; Omar Abdelsadek Abdou Elmeligy; Mohamed A. Elmonem; Mohammed Elshaer; Ibrahim Elsohaby; Amir Emami Zeydi; Luchuo Engelbert Bain; Sharareh Eskandarieh; Francesco Esposito; Kara Estep; Farshid Etaee; Natalia Fabin; Adeniyi Francis Fagbamigbe; Saman Fahimi; Aliasghar Fakhri-Demeshghieh; Luca Falzone; Ali Faramarzi; MoezAlIslam Ezzat Mahmoud Faris; Sam Farmer; Andre Faro; Abidemi Omolara Fasanmi; Ali Fatehizadeh; Nelsensius Klau Fauk; Pooria Fazeli; Valery L. Feigin; Seyed-Mohammad Fereshtehnejad; Abdullah Hamid Feroze; Pietro Ferrara; Nuno Ferreira; Getahun Fetensa; Irina Filip; Florian Fischer; Joanne Flavel; Nataliya A. Foigt; Morenike Oluwatoyin Folayan; Artem Alekseevich Fomenkov; Behzad Foroutan; Matteo Foschi; Kayode Raphael Fowobaje; Kate Louise Francis; Alberto Freitas; Takeshi Fukumoto; John E. Fuller; Blima Fux; Peter Andras Gaal; Muktar A. Gadanya; Abhay Motiramji Gaidhane; Yaseen Galali; Silvano Gallus; Aravind P. Gandhi; Balasankar Ganesan; Mohammad Arfat Ganiyani; M.A. Garcia-Gordillo; Naval Garg; Rupesh K. Gautam; Federica Gazzelloni; Semiu Olatunde Gbadamosi; Miglas W. Gebregergis; Mesfin Gebrehiwot; Tesfay Brhane Gebremariam; Teferi Gebru Gebremeskel; Yohannes Fikadu Geda; Simona Roxana Georgescu; Urge Gerema; Habtamu Geremew; Motuma Erena Getachew; Peter W. Gething; MohammadReza Ghasemi; Ghazal Ghasempour Dabaghi; Afsaneh Ghasemzadeh; Fariba Ghassemi; Ramy Mohamed Ghazy; Sailaja Ghimire; Asadollah Gholamian; Ali Gholamrezanezhad; Mahsa Ghorbani; Aloke Gopal Ghoshal; Arun Digambarrao Ghuge; Artyom Urievich Gil; Tiffany K. Gill; Matteo Giorgi; Alem Girmay; James C. Glasbey; Laszlo Göbölös; Amit Goel; Ali Golchin; Mahaveer Golechha; Pouya Goleij; Sameer Vali Gopalani; Houman Goudarzi; Alessandra C. Goulart; Anmol Goyal; Simon Matthew Graham; Michal Grivna; Shi-Yang Guan; Giovanni Guarducci; Mohammed Ibrahim Mohialdeen Gubari; Mesay Dechasa Gudeta; Stefano Guicciardi; Snigdha Gulati; David Gulisashvili; Damitha Asanga Gunawardane; Cui Guo; Anish Kumar Gupta; Bhawna Gupta; Manoj Kumar Gupta; Mohak Gupta; Sapna Gupta; Veer Bala Gupta; Vijai Kumar Gupta; Vivek Kumar Gupta; Annie Haakenstad; Farrokh Habibzadeh; Najah R. Hadi; Nils Haep; Ramtin Hajibeygi; Sebastian Haller; Rabih Halwani; Randah R. Hamadeh; Nadia M. Hamdy; Sajid Hameed; Samer Hamidi; Qiuxia Han; Alexis J. Handal; Graeme J. Hankey; Md Nuruzzaman Haque; Josep Maria Haro; Ahmed I. Hasaballah; Ikramul Hasan; Mohammad Jahid Hasan; S.M. Mahmudul Hasan; Hamidreza Hasani; Md Saquib Hasnain; Amr Hassan; Ikrama Hassan; Soheil Hassanipour; Hadi Hassankhani; Simon I. Hay; Jeffrey J. Hebert; Omar E. Hegazi; Mohammad Heidari; Bartosz Helfer; Mehdi Hemmati; Brenda Yuliana Herrera-Serna; Claudiu Herteliu; Kamran Hessami; Kamal Hezam; Yuta Hiraike; Nguyen Quoc Hoan; Ramesh Holla; Nobuyuki Horita; Md Mahbub Hossain; Mohammad Bellal Hossain Hossain; Hassan Hosseinzadeh; Mehdi Hosseinzadeh; Mihaela Hostiuc; Sorin Hostiuc; Mohamed Hsairi; Vivian Chia-Rong Hsieh; Chengxi Hu; Junjie Huang; M. Mamun Huda; Ayesha Humayun; Javid Hussain; Nawfal R. Hussein; Hong-Han Huynh; Bing-Fang Hwang; Segun Emmanuel Ibitoye; Pulwasha Maria Iftikhar; Olayinka Stephen Ilesanmi; Irena M. Ilic; Milena D. Ilic; Mustapha Immurana; Leeberk Raja Inbaraj; Afrin Iqbal; Md. Rabiul Islam; Nahlah Elkudssiah Ismail; Hiroyasu Iso; Gaetano Isola; Masao Iwagami; Mahalaxmi Iyer; J. Linda Merin; Jalil Jaafari; Louis Jacob; Farhad Jadidi-Niaragh; Khushleen Jaggi; Kasra Jahankhani; Nader Jahanmehr; Haitham Jahrami; Akhil Jain; Nityanand Jain; Ammar Abdulrahman Jairoun; Mihajlo Jakovljevic; Elham Jamshidi; Sabzali Javadov; Tahereh Javaheri; Sathish Kumar Jayapal; Shubha Jayaram; Sun Ha Jee; Jayakumar Jeganathan; Anil K. Jha; Ravi Prakash Jha; Heng Jiang; Mohammad Jokar; Jost B. Jonas; Tamas Joo; Nitin Joseph; Charity Ehimwenma Joshua; Farahnaz Joukar; Jacek Jerzy Jozwiak; Mikk Jürisson; K. Vaishali; Billingsley Kaambwa; Abdulkareem Kabir; Ali Kabir; Hannaneh Kabir; Zubair Kabir; Rizwan Kalani; Leila R. Kalankesh; Feroze Kaliyadan; Sanjay Kalra; Rajesh Kamath; Sagarika Kamath; Tanuj Kanchan; Edmund Wedam Kanmiki; Kehinde Kazeem Kanmodi; S. Suthanthira Kannan; Sushil Kumar Kansal; Rami S. Kantar; Neeti Kapoor; Mehrdad Karajizadeh; Manoochehr Karami; Ibraheem M. Karaye; Faizan Zaffar Kashoo; Hengameh Kasraei; Nicholas J. Kassebaum; Molly B. Kassel; Joonas H. Kauppila; Foad Kazemi; Sara Kazeminia; John H. Kempen; Evie Shoshannah Kendal; Kamyab Keshtkar; Mohammad Keykhaei; Himanshu Khajuria; Amirmohammad Khalaji; Nauman Khalid; Anees Ahmed Khalil; Alireza Khalilian; Faham Khamesipour; Ajmal Khan; Asaduzzaman Khan; Ikramullah Khan; M. Nuruzzaman Khan; Maseer Khan; Mohammad Jobair Khan; Moien A.B. Khan; Young-Ho Khang; Shaghayegh Khanmohammadi; Khaled Khatab; Armin Khavandegar; Hamid Reza Khayat Kashani; Feriha Fatima Khidri; Moein Khormali; Mohammad Ali Khosravi; Mahmood Khosrowjerdi; Wondwosen Teklesilasie Kidane; Zemene Demelash Kifle; Julie Sojin Kim; Min Seo Kim; Ruth W. Kimokoti; Kasey E. Kinzel; Girmay Tsegay Kiross; Adnan Kisa; Sezer Kisa; Ali-Asghar Kolahi; Farzad Kompani; Gerbrand Koren; Oleksii Korzh; Soewarta Kosen; Sindhura Lakshmi Koulmane Laxminarayana; Kewal Krishan; Varun Krishna; Vijay Krishnamoorthy; Barthelemy Kuate Defo; Connor M. Kubeisy; Burcu Kucuk Bicer; Md Abdul Kuddus; Mohammed Kuddus; Ilari Kuitunen; Mukhtar Kulimbet; Harish Kumar; Satyajit Kundu; Kunle Rotimi Kunle; Om P. Kurmi; Asep Kusnali; Dian Kusuma; Evans F. Kyei; Ilias Kyriopoulos; Carlo La Vecchia; Ben Lacey; Muhammad Awwal Ladan; Lucie Laflamme; Chandrakant Lahariya; Daphne Teck Ching Lai; Dharmesh Kumar Lal; Ratilal Lalloo; Judit Lám; Demetris Lamnisos; Ivan Landires; Francesco Lanfranchi; Berthold Langguth; Ariane Laplante-Lévesque; Heidi Jane Larson; Anders O. Larsson; Savita Lasrado; Kamaluddin Latief; Kaveh Latifinaibin; Long Khanh Dao Le; Nhi Huu Hanh Le; Trang Diep Thanh Le; Caterina Ledda; Munjae Lee; Paul H. Lee; Seung Won Lee; Yo Han Lee; Gebretsadik Kiros Lema; Elvynna Leong; Temesgen L. Lerango; An Li; Ming-Chieh Li; Shanshan Li; Wei Li; Xiaopan Li; Virendra S. Ligade; Stephen S. Lim; Ro-Ting Lin; Paulina A. Lindstedt; Stefan Listl; Gang Liu; Jue Liu; Xiaofeng Liu; Xuefeng Liu; Yuewei Liu; Erand Llanaj; Ruben López-Bueno; Platon D. Lopukhov; Laszlo Lorenzovici; Paulo A. Lotufo; Jailos Lubinda; Giancarlo Lucchetti; Alessandra Lugo; Raimundas Lunevicius; Hengliang Lv; Zheng Feei Ma; Kelsey Lynn Maass; Monika MacHoy; Áurea M. Madureira-Carvalho; Mohammed Magdy Abd El Razek; Azzam A. Maghazachi; Soleiman Mahjoub; Mansour Adam Mahmoud; Azeem Majeed; Jeadran N. Malagón-Rojas; Elaheh Malakan Rad; Kashish Malhotra; Ahmad Azam Malik; Iram Malik; Deborah Carvalho Malta; Abdullah A. Mamun; Yosef Manla; Yasaman Mansoori; Ali Mansour; Borhan Mansouri; Zeinab Mansouri; Mohammad Ali Mansournia; Joemer C. Maravilla; Mirko Marino; Abdoljalal Marjani; Gabriel Martinez; Ramon Martinez-Piedra; Francisco Rogerlandio Martins-Melo; Miquel Martorell; Sharmeen Maryam; Roy Rillera Marzo; Alireza Masoudi; Jishanth Mattumpuram; Richard James Maude; Andrea Maugeri; Erin A. May; Mahsa Mayeli; Maryam Mazaheri; John J. McGrath; Martin McKee; Anna Laura Wensel McKowen; Susan A. McLaughlin; Steven M. McPhail; Rahul Mehra; Kamran Mehrabani-Zeinabad; Entezar Mehrabi Nasab; Tesfahun Mekene Meto; Max Alberto Mendez Mendez-Lopez; Walter Mendoza; Ritesh G. Menezes; George A. Mensah; Alexios-Fotios A. Mentis; Sultan Ayoub Meo; Mohsen Merati; Atte Meretoja; Tuomo J. Meretoja; Abera M. Mersha; Tomislav Mestrovic; Pouya Metanat; Kukulege Chamila Dinushi Mettananda; Sachith Mettananda; Adquate Mhlanga; Laurette Mhlanga; Tianyue Mi; Tomasz Miazgowski; Georgia Micha; Irmina Maria Michalek; Ted R. Miller; Le Huu Nhat Minh; Mojgan Mirghafourvand; Erkin M. Mirrakhimov; Mizan Kiros Mirutse; Moonis Mirza; Roya Mirzaei; Ashim Mishra; Sanjeev Misra; Philip B. Mitchell; Chaitanya Mittal; Babak Moazen; Abdalla Z. Mohamed; Ahmed Ismail Mohamed; Jama Mohamed; Mouhand F.H. Mohamed; Nouh Saad Mohamed; Sakineh Mohammad-Alizadeh-Charandabi; Soheil Mohammadi; Abdollah Mohammadian-Hafshejani; Mustapha Mohammed; Salahuddin Mohammed; Shafiu Mohammed; Ali H. Mokdad; Peyman Mokhtarzadehazar; Hossein Molavi Vardanjani; Sabrina Molinaro; Lorenzo Monasta; Mohammad Ali Moni; Maryam Moradi; Yousef Moradi; Paula Moraga; Rafael Silveira Moreira; Negar Morovatdar; Shane Douglas Morrison; Jakub Morze; Abbas Mosapour; Elias Mossialos; Rohith Motappa; Parsa Mousavi; Amin Mousavi Khaneghah; Christine Mpundu-Kaambwa; Sumaira Mubarik; Lorenzo Muccioli; Francesk Mulita; Kavita Munjal; Efren Murillo-Zamora; Jonah Musa; Fungai Musaigwa; Ana-Maria Musina; Sathish Muthu; Saravanan Muthupandian; Muhammad Muzaffar; Woojae Myung; Ahamarshan Jayaraman Nagarajan; Gabriele Nagel; Pirouz Naghavi; Ganesh R. Naik; Gurudatta Naik; Mukhammad David Naimzada; Firzan Nainu; Vinay Nangia; Sreenivas Narasimha Swamy; Bruno Ramos Nascimento; Gustavo G. Nascimento; Abdallah Y. Naser; Mohammad Javad Nasiri; Zuhair S. Natto; Javaid Nauman; Muhammad Naveed; Biswa Prakash Nayak; Vinod C. Nayak; Rawlance Ndejjo; Sabina Onyinye Nduaguba; Hadush Negash; Chernet Tafere Negesse; Ionut Negoi; Ruxandra Irina Negoi; Seyed Aria Nejadghaderi; Chakib Nejjari; Samata Nepal; Henok Biresaw Netsere; Georges Nguefack-Tsague; Josephine W. Ngunjiri; Dang H. Nguyen; Hau Thi Hien Nguyen; Phuong The Nguyen; QuynhAnh P. Nguyen; Van Thanh Nguyen; Robina Khan Niazi; Yeshambel T. Nigatu; Taxiarchis Konstantinos Nikolouzakis; Ali Nikoobar; Amin Reza Nikpoor; Chukwudi A. Nnaji; Lawrence Achilles Nnyanzi; Efaq Ali Noman; Shuhei Nomura; Mamoona Noreen; Nafise Noroozi; Chisom Adaobi Nri-Ezedi; Mengistu H. Nunemo; Virginia Nuñez-Samudio; Dieta Nurrika; Jerry John Nutor; Bogdan Oancea; Kehinde O. Obamiro; Ismail A. Odetokun; Nkechi Martina Odogwu; Martin James O'Donnell; Oluwakemi Ololade Odukoya; Ayodipupo Sikiru Oguntade; James Odhiambo Oguta; In-Hwan Oh; Sylvester Reuben Okeke; Akinkunmi Paul Okekunle; Osaretin Christabel Okonji; Patrick Godwin Okwute; Andrew T. Olagunju; Omotola O. Olasupo; Matthew Idowu Olatubi; Glaucia Maria Moraes Oliveira; Bolajoko Olubukunola Olusanya; Jacob Olusegun Olusanya; Gideon Olamilekan Oluwatunase; Hany A. Omar; Goran Latif Omer; Obinna E. Onwujekwe; Michal Ordak; Orish Ebere Orisakwe; Verner N. Orish; Doris V. Ortega-Altamirano; Alberto Ortiz; Esteban Ortiz-Prado; Wael M.S. Osman; Uchechukwu Levi Osuagwu; Olayinka Osuolale; Adrian Otoiu; Stanislav S. Otstavnov; Amel Ouyahia; Guoqing Ouyang; Mayowa O. Owolabi; Yaz Ozten; P.A. Mahesh Padukudru; Mohammad Taha Pahlevan Fallahy; Feng Pan; Hai-Feng Pan; Adrian Pana; Paramjot Panda; Songhomitra Panda-Jonas
Background: Accurate assessments of current and future fertility—including overall trends and changing population age structures across countries and regions—are essential to help plan for the profound social, economic, environmental, and geopolitical challenges that these changes will bring. Estimates and projections of fertility are necessary to inform policies involving resource and health-care needs, labour supply, education, gender equality, and family planning and support. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 produced up-to-date and comprehensive demographic assessments of key fertility indicators at global, regional, and national levels from 1950 to 2021 and forecast fertility metrics to 2100 based on a reference scenario and key policy-dependent alternative scenarios. Methods: To estimate fertility indicators from 1950 to 2021, mixed-effects regression models and spatiotemporal Gaussian process regression were used to synthesise data from 8709 country-years of vital and sample registrations, 1455 surveys and censuses, and 150 other sources, and to generate age-specific fertility rates (ASFRs) for 5-year age groups from age 10 years to 54 years. ASFRs were summed across age groups to produce estimates of total fertility rate (TFR). Livebirths were calculated by multiplying ASFR and age-specific female population, then summing across ages 10–54 years. To forecast future fertility up to 2100, our Institute for Health Metrics and Evaluation (IHME) forecasting model was based on projections of completed cohort fertility at age 50 years (CCF50; the average number of children born over time to females from a specified birth cohort), which yields more stable and accurate measures of fertility than directly modelling TFR. CCF50 was modelled using an ensemble approach in which three sub-models (with two, three, and four covariates variously consisting of female educational attainment, contraceptive met need, population density in habitable areas, and under-5 mortality) were given equal weights, and analyses were conducted utilising the MR-BRT (meta-regression—Bayesian, regularised, trimmed) tool. To capture time-series trends in CCF50 not explained by these covariates, we used a first-order autoregressive model on the residual term. CCF50 as a proportion of each 5-year ASFR was predicted using a linear mixed-effects model with fixed-effects covariates (female educational attainment and contraceptive met need) and random intercepts for geographical regions. Projected TFRs were then computed for each calendar year as the sum of single-year ASFRs across age groups. The reference forecast is our estimate of the most likely fertility future given the model, past fertility, forecasts of covariates, and historical relationships between covariates and fertility. We additionally produced forecasts for multiple alternative scenarios in each location: the UN Sustainable Development Goal (SDG) for education is achieved by 2030; the contraceptive met need SDG is achieved by 2030; pro-natal policies are enacted to create supportive environments for those who give birth; and the previous three scenarios combined. Uncertainty from past data inputs and model estimation was propagated throughout analyses by taking 1000 draws for past and present fertility estimates and 500 draws for future forecasts from the estimated distribution for each metric, with 95% uncertainty intervals (UIs) given as the 2·5 and 97·5 percentiles of the draws. To evaluate the forecasting performance of our model and others, we computed skill values—a metric assessing gain in forecasting accuracy—by comparing predicted versus observed ASFRs from the past 15 years (2007–21). A positive skill metric indicates that the model being evaluated performs better than the baseline model (here, a simplified model holding 2007 values constant in the future), and a negative metric indicates that the evaluated model performs worse than baseline. Findings: During the period from 1950 to 2021, global TFR more than halved, from 4·84 (95% UI 4·63–5·06) to 2·23 (2·09–2·38). Global annual livebirths peaked in 2016 at 142 million (95% UI 137–147), declining to 129 million (121–138) in 2021. Fertility rates declined in all countries and territories since 1950, with TFR remaining above 2·1—canonically considered replacement-level fertility—in 94 (46·1%) countries and territories in 2021. This included 44 of 46 countries in sub-Saharan Africa, which was the super-region with the largest share of livebirths in 2021 (29·2% [28·7–29·6]). 47 countries and territories in which lowest estimated fertility between 1950 and 2021 was below replacement experienced one or more subsequent years with higher fertility; only three of these locations rebounded above replacement levels. Future fertility rates were projected to continue to decline worldwide, reaching a global TFR of 1·83 (1·59–2·08) in 2050 and 1·59 (1·25–1·96) in 2100 under the reference scenario. The number of countries and territories with fertility rates remaining above replacement was forecast to be 49 (24·0%) in 2050 and only six (2·9%) in 2100, with three of these six countries included in the 2021 World Bank-defined low-income group, all located in the GBD super-region of sub-Saharan Africa. The proportion of livebirths occurring in sub-Saharan Africa was forecast to increase to more than half of the world's livebirths in 2100, to 41·3% (39·6–43·1) in 2050 and 54·3% (47·1–59·5) in 2100. The share of livebirths was projected to decline between 2021 and 2100 in most of the six other super-regions—decreasing, for example, in south Asia from 24·8% (23·7–25·8) in 2021 to 16·7% (14·3–19·1) in 2050 and 7·1% (4·4–10·1) in 2100—but was forecast to increase modestly in the north Africa and Middle East and high-income super-regions. Forecast estimates for the alternative combined scenario suggest that meeting SDG targets for education and contraceptive met need, as well as implementing pro-natal policies, would result in global TFRs of 1·65 (1·40–1·92) in 2050 and 1·62 (1·35–1·95) in 2100. The forecasting skill metric values for the IHME model were positive across all age groups, indicating that the model is better than the constant prediction. Interpretation: Fertility is declining globally, with rates in more than half of all countries and territories in 2021 below replacement level. Trends since 2000 show considerable heterogeneity in the steepness of declines, and only a small number of countries experienced even a slight fertility rebound after their lowest observed rate, with none reaching replacement level. Additionally, the distribution of livebirths across the globe is shifting, with a greater proportion occurring in the lowest-income countries. Future fertility rates will continue to decline worldwide and will remain low even under successful implementation of pro-natal policies. These changes will have far-reaching economic and societal consequences due to ageing populations and declining workforces in higher-income countries, combined with an increasing share of livebirths among the already poorest regions of the world. Funding: Bill & Melinda Gates Foundation. © 2024 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license
Synthesis and catalytic activity of Cu-Cr-O-TiO2 composites for the thermal decomposition of ammonium per-chlorate: enhanced decomposition rate of fuel for solid rocket motors
(Royal Society of Chemistry, 2017) Harish Kumar; Prahalad N. Tengli; Vijay Kumar Mishra; Pankaj Tripathi; Dan Bahadur Pal; Pradeep Kumar Mishra
This study presents the sol-gel synthesis of Cu-Cr-O·nTiO2 particles calcined at different temperatures and their catalytic effects on thermal decompostion of AP. The study focuses on the impact of crystallite size, shape and concentration of TiO2 in the catalyst composition on the thermal decomposition behaviour of ammonium per-chlorate (AP). During synthesis, the molar ratio of Cu/Cr was kept to 0.7 and TiO2 nanoparticles were added into Cu-Cr-O-citric acid solution at different molar ratios to form three different compositions of the catalyst Cu-Cr-O·nTiO2 (n = 0.5, 0.7 and 0.9 mol%). The effect of temperature on the thermal, structural and spectroscopic properties of the different Cu-Cr-O compositions was also studied by calcining them at two different temperatures, 300 and 1050 °C. Post synthesis characterizations of the prepared catalysts were carried out by using XRD, FT-IR, SEM, EDAX and TEM (with SAED pattern) techniques. The desired qualification of Cu-Cr-O-citric acid (the precursor of the catalyst) and the final compositions of the catalysts were carried out by using thermogravimetric and differential thermal analysis (TG-DTA) techniques. The efficiency of the synthesized catalysts was evaluated on thermal decomposition behaviour of AP using TG-DTA techniques. The Cu-Cr-O·nTiO2 composition with the molar ratio of n = 0.7 was found to be the most efficient catalyst for decomposition of AP; it was much better than other laboratory prepared samples (n = 0.5 and 0.9) as well as the industrial catalyst (i.e. activated copper chromite (ACR); Cu-Cr-O). Further experimental work showed that addition of 10 wt% Cu-Cr-O·0.7TiO2 into AP significantly lowered the AP decomposition temperature to 306 °C from 385 °C and was accompanied by a very sharp exothermic peak indicating a single stage decomposition. The excellent finding of the study was also verified by heat of reaction (i.e. calibrated delta H) values. This study finds potential application due to the remarkable enhancement in the thermal decomposition rate of the AP used as oxidizer in propellant of solid rocket motors (SRMs) and space vehicles (SVs) at lower decomposition temperature. The fast decomposition rate of oxidizer at lower decomposition temperature enhances the efficiency of fuel which ultimately will enhance the efficiency of SRMs and SVs. © The Royal Society of Chemistry.
The effect of reduced graphene oxide on the catalytic activity of Cu-Cr-O-TiO2 to enhance the thermal decomposition rate of ammonium perchlorate: An efficient fuel oxidizer for solid rocket motors and missiles
(Royal Society of Chemistry, 2017) Harish Kumar; Prahalad N. Tengli; Vijay Kumar Mishra; Pankaj Tripathi; Awani Bhushan; Pradeep Kumar Mishra
Reduced graphene oxide (rGO) modified transition metal oxide based composites were successfully synthesized via a sol-gel assisted Hummers' method. The present study includes the synthesis of CuCr2O4·0.7TiO2, the synthesis of rGO and the synthesis of rGO modified CuCr2O4·0.7TiO2. In order to synthesize the desired catalyst, rGO and Cu-Cr-O-0.7TiO2 were synthesized individually. The CuCr2O4·0.7TiO2 composite was synthesized via a sol-gel method. Reduced graphene oxide (rGO) used as a modifier in the catalyst, was also synthesized in the laboratory and was calcined at high temperature (1050 °C) to improve its activity. Finally, Cu-Cr-O-0.7TiO2 was modified with 10 wt% rGO. The post synthesis characterizations were performed using various instrumental techniques including X-ray diffraction (XRD) for phase analysis, Fourier transform infrared (FTIR) and Raman spectroscopy for molecular interactions, scanning electron microscopy (SEM) for surface morphology, energy dispersive X-ray analysis (EDX), elemental analysis and X-ray photoelectron spectroscopy (XPS) for binding energy. The catalytic efficiency of the synthesized composite catalyst samples based thermal decomposition of the host material (i.e. AP) was determined by differential thermal analysis (DTA) and thermogravimetric analysis (TGA). The rGO modification into the Cu-Cr-O-0.7TiO2 tri-metallic composition made it the most promising catalyst for the thermal decomposition of AP, due to the tremendously high electrical and thermal conductivity of rGO. Different amounts (2.5, 5.0, 7.5 and 10 wt%) of Cu-Cr-O-0.7TiO2-rGO were added to ammonium perchlorate (AP) to investigate its effect on the thermal decomposition of AP, which is a well known oxidizer used worldwide in the solid composite propellant (SCP) in modern rocketry. The 5 wt% of catalyst (Cu-Cr-O-0.7TiO2-rGO) addition into AP exhibited the remarkably enhanced thermal decomposition of AP. Finally, the burn rate of SCP was examined with 5 wt% catalyst modified AP. The 5 wt% of catalyst modified AP exhibited 175.31% higher burn rate of SCP, compared to the burn rate of pure AP added SCP. Furthermore, when it was compared with an industrial catalyst, i.e. activated copper chromite (ACR), it showed 133.61% higher burn rate of SCP. The SCP exhibited excellent ballistic performance with 0.6% of catalyst in AP, which enhanced the burn rate from 4.866 mm s-1 (for SCP having pure AP) to 8.531 mm s-1 (for SCP having catalyst added AP) and 6.385 mm s-1 (for SCP having industrial catalyst added AP) at 33 bar. © 2017 The Royal Society of Chemistry.