Zero-dimensional model for a 4-stroke, direct injection, variable compression ratio for maximum torque

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.dc201

Population and fertility by age and sex for 195 countries and territories, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017

Background: Population estimates underpin demographic and epidemiological research and are used to track progress on numerous international indicators of health and development. To date, internationally available estimates of population and fertility, although useful, have not been produced with transparent and replicable methods and do not use standardised estimates of mortality. We present single-calendar year and single-year of age estimates of fertility and population by sex with standardised and replicable methods. Methods: We estimated population in 195 locations by single year of age and single calendar year from 1950 to 2017 with standardised and replicable methods. We based the estimates on the demographic balancing equation, with inputs of fertility, mortality, population, and migration data. Fertility data came from 7817 location-years of vital registration data, 429 surveys reporting complete birth histories, and 977 surveys and censuses reporting summary birth histories. We estimated age-specific fertility rates (ASFRs; the annual number of livebirths to women of a specified age group per 1000 women in that age group) by use of spatiotemporal Gaussian process regression and used the ASFRs to estimate total fertility rates (TFRs; the average number of children a woman would bear if she survived through the end of the reproductive age span [age 10–54 years] and experienced at each age a particular set of ASFRs observed in the year of interest). Because of sparse data, fertility at ages 10–14 years and 50–54 years was estimated from data on fertility in women aged 15–19 years and 45–49 years, through use of linear regression. Age-specific mortality data came from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 estimates. Data on population came from 1257 censuses and 761 population registry location-years and were adjusted for underenumeration and age misreporting with standard demographic methods. Migration was estimated with the GBD Bayesian demographic balancing model, after incorporating information about refugee migration into the model prior. Final population estimates used the cohort-component method of population projection, with inputs of fertility, mortality, and migration data. Population uncertainty was estimated by use of out-of-sample predictive validity testing. With these data, we estimated the trends in population by age and sex and in fertility by age between 1950 and 2017 in 195 countries and territories. Findings: From 1950 to 2017, TFRs decreased by 49\ub74% (95% uncertainty interval [UI] 46\ub74–52\ub70). The TFR decreased from 4\ub77 livebirths (4\ub75–4\ub79) to 2\ub74 livebirths (2\ub72–2\ub75), and the ASFR of mothers aged 10–19 years decreased from 37 livebirths (34–40) to 22 livebirths (19–24) per 1000 women. Despite reductions in the TFR, the global population has been increasing by an average of 83\ub78 million people per year since 1985. The global population increased by 197\ub72% (193\ub73–200\ub78) since 1950, from 2\ub76 billion (2\ub75–2\ub76) to 7\ub76 billion (7\ub74–7\ub79) people in 2017; much of this increase was in the proportion of the global population in south Asia and sub-Saharan Africa. The global annual rate of population growth increased between 1950 and 1964, when it peaked at 2\ub70%; this rate then remained nearly constant until 1970 and then decreased to 1\ub71% in 2017. Population growth rates in the southeast Asia, east Asia, and Oceania GBD super-region decreased from 2\ub75% in 1963 to 0\ub77% in 2017, whereas in sub-Saharan Africa, population growth rates were almost at the highest reported levels ever in 2017, when they were at 2\ub77%. The global average age increased from 26\ub76 years in 1950 to 32\ub71 years in 2017, and the proportion of the population that is of working age (age 15–64 years) increased from 59\ub79% to 65\ub73%. At the national level, the TFR decreased in all countries and territories between 1950 and 2017; in 2017, TFRs ranged from a low of 1\ub70 livebirths (95% UI 0\ub79–1\ub72) in Cyprus to a high of 7\ub71 livebirths (6\ub78–7\ub74) in Niger. The TFR under age 25 years (TFU25; number of livebirths expected by age 25 years for a hypothetical woman who survived the age group and was exposed to current ASFRs) in 2017 ranged from 0\ub708 livebirths (0\ub707–0\ub709) in South Korea to 2\ub74 livebirths (2\ub72–2\ub76) in Niger, and the TFR over age 30 years (TFO30; number of livebirths expected for a hypothetical woman ageing from 30 to 54 years who survived the age group and was exposed to current ASFRs) ranged from a low of 0\ub73 livebirths (0\ub73–0\ub74) in Puerto Rico to a high of 3\ub71 livebirths (3\ub70–3\ub72) in Niger. TFO30 was higher than TFU25 in 145 countries and territories in 2017. 33 countries had a negative population growth rate from 2010 to 2017, most of which were located in central, eastern, and western Europe, whereas population growth rates of more than 2\ub70% were seen in 33 of 46 countries in sub-Saharan Africa. In 2017, less than 65% of the national population was of working age in 12 of 34 high-income countries, and less than 50% of the national population was of working age in Mali, Chad, and Niger. Interpretation: Population trends create demographic dividends and headwinds (ie, economic benefits and detriments) that affect national economies and determine national planning needs. Although TFRs are decreasing, the global population continues to grow as mortality declines, with diverse patterns at the national level and across age groups. To our knowledge, this is the first study to provide transparent and replicable estimates of population and fertility, which can be used to inform decision making and to monitor progress. Funding: Bill & Melinda Gates Foundation

Global, regional, and national age-sex-specific mortality and life expectancy, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017

BACKGROUND: Assessments of age-specific mortality and life expectancy have been done by the UN Population Division, Department of Economics and Social Affairs (UNPOP), the United States Census Bureau, WHO, and as part of previous iterations of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD). Previous iterations of the GBD used population estimates from UNPOP, which were not derived in a way that was internally consistent with the estimates of the numbers of deaths in the GBD. The present iteration of the GBD, GBD 2017, improves on previous assessments and provides timely estimates of the mortality experience of populations globally. METHODS: The GBD uses all available data to produce estimates of mortality rates between 1950 and 2017 for 23 age groups, both sexes, and 918 locations, including 195 countries and territories and subnational locations for 16 countries. Data used include vital registration systems, sample registration systems, household surveys (complete birth histories, summary birth histories, sibling histories), censuses (summary birth histories, household deaths), and Demographic Surveillance Sites. In total, this analysis used 8259 data sources. Estimates of the probability of death between birth and the age of 5 years and between ages 15 and 60 years are generated and then input into a model life table system to produce complete life tables for all locations and years. Fatal discontinuities and mortality due to HIV/AIDS are analysed separately and then incorporated into the estimation. We analyse the relationship between age-specific mortality and development status using the Socio-demographic Index, a composite measure based on fertility under the age of 25 years, education, and income. There are four main methodological improvements in GBD 2017 compared with GBD 2016: 622 additional data sources have been incorporated; new estimates of population, generated by the GBD study, are used; statistical methods used in different components of the analysis have been further standardised and improved; and the analysis has been extended backwards in time by two decades to start in 1950. FINDINGS: Globally, 18·7% (95% uncertainty interval 18·4–19·0) of deaths were registered in 1950 and that proportion has been steadily increasing since, with 58·8% (58·2–59·3) of all deaths being registered in 2015. At the global level, between 1950 and 2017, life expectancy increased from 48·1 years (46·5–49·6) to 70·5 years (70·1–70·8) for men and from 52·9 years (51·7–54·0) to 75·6 years (75·3–75·9) for women. Despite this overall progress, there remains substantial variation in life expectancy at birth in 2017, which ranges from 49·1 years (46·5–51·7) for men in the Central African Republic to 87·6 years (86·9–88·1) among women in Singapore. The greatest progress across age groups was for children younger than 5 years; under-5 mortality dropped from 216·0 deaths (196·3–238·1) per 1000 livebirths in 1950 to 38·9 deaths (35·6–42·83) per 1000 livebirths in 2017, with huge reductions across countries. Nevertheless, there were still 5·4 million (5·2–5·6) deaths among children younger than 5 years in the world in 2017. Progress has been less pronounced and more variable for adults, especially for adult males, who had stagnant or increasing mortality rates in several countries. The gap between male and female life expectancy between 1950 and 2017, while relatively stable at the global level, shows distinctive patterns across super-regions and has consistently been the largest in central Europe, eastern Europe, and central Asia, and smallest in south Asia. Performance was also variable across countries and time in observed mortality rates compared with those expected on the basis of development. INTERPRETATION: This analysis of age-sex-specific mortality shows that there are remarkably complex patterns in population mortality across countries. The findings of this study highlight global successes, such as the large decline in under-5 mortality, which reflects significant local, national, and global commitment and investment over several decades. However, they also bring attention to mortality patterns that are a cause for concern, particularly among adult men and, to a lesser extent, women, whose mortality rates have stagnated in many countries over the time period of this study, and in some cases are increasing

Crystallization kinetics of overlapping phases in Se70Te15Sb15 using isoconversional methods

The crystallization kinetics of Se70Te15Sb15 chalcogenide glass was studied by Differential Scanning Calorimetry (DSC) under non-isothermal conditions. This glass was found to have a double glass transition and double overlapped crystalline phases. The overlapped crystalline phases were successfully separated using the Gaussian fit model. The activation energy, Ec, and Avrami index, n, were determined by analyzing the data using the Matausita et. al. method. A strong heating rate depending on the activation energy for the two crystalline peaks was observed. The results indicated that the transformation from amorphous to crystalline phases is a complex process involving different mechanisms of nucleation and growth. The variation of activation energy with crystalline fraction was determined by Kissenger–Akahira–Sunose (KAS) method. The obtained results of directly fitting the experimental DSC data to the calculated DSC curves indicated that the crystallization process of Se70Te15Sb15 glass cannot be satisfactorily described by the Johnson–Mehl–Avrami (JMA) model. Simulation results indicated that the Sestak–Berggren (SB) model is more suitable to describe the crystallization process for the studied glass. The crystalline phases for the two events were identified by using x-ray diffraction (XRD) and scanning electron microscopy (SEM)

Preparation of quantum size of tin oxide: Structural and physical characterization

SnO2 NPs were successfully prepared via a hydrothermal method. X-ray diffraction analysis confirmed the rutile tetragonal structure of SnO2 NPs. The crystallite size increased from 1.18 to 5.06 nm with increasing the preparation temperature from 100 to 180 °C. The SEM photography of the products exhibited the agglomeration of the SnO2 nanocrystals to large view particles, while TEM images confirmed the polycrystalline phase and crystallite size those analyzed from XRD. The UV–vis absorption of ethanol suspended SnO2 NPs was measured. The optical band-gap energies (Eg) were significantly blue-shifted due to quantum confinement. Fluorescence spectra came to confirm this shift, where a clear shift in the maximum emission peak was observed. Stokes shift of SnO2 nanocrystals was found to be crystallite size dependent

Determination of activation energy of amorphous to crystalline transformation for Se90Te10 using isoconversional methods

The activation energies of crystallization of Se90Te10glass were studied at different heating rates (4–50 K/min)under non-isothermal conditions using a differential scanning calorimetric (DSC) technique. The activation ener-gy was determined by analyzing the data using the Matusita et al. method. A strong heating rate dependence ofthe activation energy was observed. The variation of the activation energy was analyzed by the application of thethree isoconversional methods, of Kissinger–Akahira–Sunose (KAS), Flynn–Wall–Ozawa (FWO), and Vyazovkin.These methods confirm that the activation energy of crystallization is not constant but varies with the degree ofcrystallization and hence with temperature. This variation indicates that the transformation from amorphous tocrystalline phase is a complex process involving different mechanisms of nucleation and growth. On the otherhand, the validity of the Johnson–Mehl–Avrami (JMA) model to describe the crystallization process for thestudied composition was discussed. Results obtained by directlyfitting the experimental DSC to the calculatedDSC curve indicate that the crystallization process of the Se90Te10glass cannot be satisfactorily described bythe JMA model. In general, simulation results indicate that the Sestak–Berggren (SB) model is more suitable todescribe the crystallization kinetic

Annealing effect on structural and optical properties of Se87.5Te10Sn2.5 thin films

Thin films of Se87.5Te10Sn2.5 were prepared by vacuum thermal evaporation technique. Various optical constants were calculated for the studied composition. The mechanism of the optical absorption follows the rule of direct transition. It was found that the optical energy gap (Eg) decreases from 2.26 to 1.79 eV with increasing the annealing temperature from 340 to 450 K. This result can be interpreted by the Davis and Mott model. On the other hand, the maximum value of the refractive index (n) is shifted towards the long wavelength by increasing the annealing temperature. In addition, the high frequency dielectric constant (εL) increased from 31.26 to 48.11 whereas the ratio of the free carriers concentration to its effective of mass N/m⁎ decreased from 4.3 to 2.09 (×1057 (m−3 Kg−1)). The influence of annealed temperature on the structure was studied by using the X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD studies show that the as-deposited films are amorphous in nature, but the crystallinity improved with increasing the annealing temperature. Furthermore the particle size and crystallinity increased whereas the dislocation and strains decreased with increasing the annealing temperature. SEM examination showed that the annealing temperature induced changes in the morphology of the as-deposited film

Optical and other physical characteristics of amorphous Se–Te–Sn alloys

The Effect of Sn addition in the structural and optical properties of Se–Te chalcogenide alloy at the expense of the Se content has been studied. Stoichiometric bulk ingot materials of the Se90−xTe10Snx (x=0, 2.5, 5 and 7.5 at%) were prepared by a melt-quench technique. X-ray diffraction (XRD) studies indicated that the investigated alloys confirmed its amorphous nature. These results were confirmed by scanning electron microscopy (SEM) investigations and correlated to the rigidity percolation threshold of the lattice. Stoichiometric thermally evaporated thin film of the obtained compositions were carefully characterized to establish the interdependence between their chemical composition and some physical parameters, such as the average heat of atomization (Hs), the cohesive energy CE, the average coordination number 〈Z〉 and the optical band gap (Eg). It has been found that all the parameters varied linearly when Sn content was increased. The variation in the optical band gap (Eg) with Sn addition was discussed in terms of the width of localized states (Ee) and a chemical bond approach model (CBA)

Effect of Sn substitution for Se on dispersive optical constants of amorphous Se–Te–Sn thin films

Optical constants of vacuum evaporated thin films in the Se90−xTe10Snx (x = 0, 2.5, 5 and 7.5 at %) system were calculated from reflectance and transmittance data in the wavelength range of 300–2500 nm using Murmann’s equations. The maximum value of refractive index increased and suffered a shift towards the short wavelength as the Sn content increases this behavior can be attributed to increasing the values of cross-linking chains density and decrease tailing. The variations in the real and the imaginary parts of the dielectric constant, the dissipation factor tan(δ), the optical conductivity, the volume, and surface energy loss functions with photon energy have also been reported. The normal dispersion of the refractive index is discussed regarding the single oscillator Wemple-DiDomenico model from which the dispersion parameters were determined. The single oscillator energy, the dispersion energy, the high-frequency dielectric constant, the ratio of free charge carrier concentration to the effective mass, plasma frequency, single oscillator strength and its position are then estimated as a function of alloy composition. It is interesting to note that the increase of Sn content on the parent Se90Te10 is connected to the decreasing covalent nature of the structure. Besides, the presence of such a sharp absorption edge in transmission spectra recommends Se90−xTe10Snx thin films as a good optical filter materia

Determination of activation energy of amorphous to crystalline transformation for Se90Te10 using isoconversional methods

The activation energies of crystallization of Se90Te10 glass were studied at different heating rates (4–50 K/min) under non-isothermal conditions using a differential scanning calorimetric (DSC) technique. The activation energy was determined by analyzing the data using the Matusita et al. method. A strong heating rate dependence of the activation energy was observed. The variation of the activation energy was analyzed by the application of the three isoconversional methods, of Kissinger–Akahira–Sunose (KAS), Flynn–Wall–Ozawa (FWO), and Vyazovkin. These methods confirm that the activation energy of crystallization is not constant but varies with the degree of crystallization and hence with temperature. This variation indicates that the transformation from amorphous to crystalline phase is a complex process involving different mechanisms of nucleation and growth. On the other hand, the validity of the Johnson–Mehl–Avrami (JMA) model to describe the crystallization process for the studied composition was discussed. Results obtained by directly fitting the experimental DSC to the calculated DSC curve indicate that the crystallization process of the Se90Te10 glass cannot be satisfactorily described by the JMA model. In general, simulation results indicate that the Sestak–Berggren (SB) model is more suitable to describe the crystallization kinetics