Time and Amplitude of Afterpulse Measured with a Large Size Photomultiplier Tube

We have studied the afterpulse of a hemispherical photomultiplier tube for an upcoming reactor neutrino experiment. The timing, the amplitude, and the rate of the afterpulse for a 10 inch photomultiplier tube were measured with a 400 MHz FADC up to 16 \ms time window after the initial signal generated by an LED light pulse. The time and amplitude correlation of the afterpulse shows several distinctive groups. We describe the dependencies of the afterpulse on the applied high voltage and the amplitude of the main light pulse. The present data could shed light upon the general mechanism of the afterpulse.Comment: 11 figure

An Observational Overview of Solar Flares

We present an overview of solar flares and associated phenomena, drawing upon a wide range of observational data primarily from the RHESSI era. Following an introductory discussion and overview of the status of observational capabilities, the article is split into topical sections which deal with different areas of flare phenomena (footpoints and ribbons, coronal sources, relationship to coronal mass ejections) and their interconnections. We also discuss flare soft X-ray spectroscopy and the energetics of the process. The emphasis is to describe the observations from multiple points of view, while bearing in mind the models that link them to each other and to theory. The present theoretical and observational understanding of solar flares is far from complete, so we conclude with a brief discussion of models, and a list of missing but important observations.Comment: This is an article for a monograph on the physics of solar flares, inspired by RHESSI observations. The individual articles are to appear in Space Science Reviews (2011

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

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Effect of Gamma Irradiation on the Thermal Decomposition Behaviour and Electrical Resistivity of Some Indian Lignite and Bituminous Coals

189-193It is known that irradiation of coal by high-energy and ionising gamma rays affects the structure of coal, as a result of which its physical and chemical properties are also likely to be - and indeed are, affected or modified. Very little work has been on this aspect of Indian coals, which are quite different from their foreign counterparts. From this point of view, over the past some years, the effect of gamma irradiation on different types of Indian coals and lignites have been extensively investigated at the Central Fuel Research Institute, Dhanbad. The work reported here is a part of those studies. Since thermal decomposition behaviour of coal is quite important for the selection of a suitable type of coal to be used in the coal hydrogenation process and also since the electrical resistivity of coal too is an important property which is imperatively considered in the non-fuel use of coal - especially for the manufacture of carbon artifacts (e.g. graphite, electrodes etc.), it prompted us to investigate as to whether the irradiation of coal with gamma rays affects its thermal decomposition behaviour and its electrical resistivity and, if so, to what extent and how will it be useful technologically. Presented in this paper are the results of investigations on the effect of gamma irradiation on the thermal decomposition/transformation of Rajasthan lignite and bituminous coal of Raniganj (West Bengal) coalfield and also on the electrical resistivity of high volatile, non-coking Hariajam (Gopinathpur seam) coal of Raniganj coalfields.   The results of these investigations have evidenced that at a maximum gamma dose of 120 Mrad, the thermal decomposition behaviour of both the Rajasthan lignite and bituminous Raniganj coal is significantly affected and eventually their transformation takes place. A comparison of the differential thermal analysis (DTA) curves of the unirradiated and irradiated coal and lignite samples reveals that in the DTA curves of irrradiated lignite and bituminous coal, additional endothermic and exothermic peaks appear.Whereas exothermic peaks correspond to solidifying temperature, the exothermic peaks connote temperature of maximum fluidity and decomposition and vapourisation of lower molecular weight constituents. Likewise, the results on the effect of gamma irradiation on high volatile, non-coking Hariajam coal clearly shows that the electrical resistivity of this coal is greatly affected. It has been found that in the beginning, upto a gamma dose of 150 Mrad, the electrical resistivity decreases, but at doses higher than this, the electrical resistivity gradually increases at all the temperatures studied (viz. 200, 500. and 800oC) and at 800oC it shoots up abruptly, attaining maximum value.  The results of these investigations have been explained on the basis of degradation and polycondensation as also the cross-linking of molecules that take place in coal under the influence of gamma rays. In conclusion, it is inferred from these studies that whereas the changes/modifications brought out in the thermal decomposition behaviour of Rajasthan lignite and bituminous Raniganj coal after gamma irradiation can be advantageously exploited in the use of these coals in the coal hydrogenation process, the increased electrical resistivity of non-coking Hariajam coal will he potentially useful in the manufacture of coke and other carbon artifacts like graphite and carbon electrodes

Investigations on desulphurisation of some high-sulphur Indian coals by gamma-ray-induced chlorinolysis

Results of investigations on desulphurisation of high-sulphur (2-8 wt%) coals of Meghalaya by radiation chlorinolysis, effected in different media of chlorination (CCl4, CCl4/H2O, and CCl4/CH3OH) via radiolysis of CCl4, for the removal of both the inorganic (pyritic and sulphate) and the organic forms of sulphur as well as mineral matter are reported. In general, maximum removal of total sulphur (up to 37%) and mineral matter (up to 10%) takes place in CCl4/CH3OH medium, which is attributed to the CH3OH acting as a better wetting agent for coal. It is found that while pyritic and sulphate sulphur are removed almost quantitatively, there is variation in the removal of organic sulphur from the coals. Furthermore, the coal matrix is not affected/degraded to any appreciable extent and the caking property of the coals is either improved or slightly degraded after desulphurisation. Mechanism of desulphurisation of coal via radiation chlorination is proposed

Gamma - Radiolytic desulphurisation of some high-sulphur Indian coals catalytically accelerated by MnO2

γ-Radiolysis of acidic aqueous coal slurries is a novel and effective method for the simultaneous oxidative desulphurisation and demineralisation of high-sulphur coals. This method is capable to selectively remove the inorganic and organic forms of sulphur simultaneously through the in situ-generated H2O2 and other radiolytic products. In effect, there is neither any appreciable degradation of coal matrix nor any loss in the caking property and volatile matter content of the coals after the removal of sulphur. However, significant removals of sulphur and mineral matter are effected at rather high γ -dose (175X104 Gy or so). Therefore, for the process to be economically viable and commercially adaptable, the applied γ -dose needs to be somehow substantially brought down, at which the same level of desulphurisation could be achieved. Catalytically, accelerating the radiolysis process is one such possibility to effect the desulphurization step at a low γ -dose. Reported in this paper are the results of investigations on the desulphurisation and demineralization of high-sulphur (sulphur content in the range 3–5.5%) Churphy, Chalang and Bapung coals of Meghalaya by γ -radiolytic process catalysed by MnO2. The maximum removal of total sulphur (15.6%, 30.0% and 29.8%) at 30 X 104 Gy in the presence of MnO2 and the simultaneous removal of mineral matter (20.0% and 18.5% from Churphy and Chalang coals at 30 X 104 Gy and 12.0% from Bapung coal at 45 X 104 Gy. are at par with removals at 175 X 104 Gy without MnO2, which has been attributed to MnO2 catalytically accelerating the radiolytic process via the formation of highly reactive MnO under the action of γ -rays. All the other features of non-catalysed radiolytic desulphurisation such as stabilisation of the slurry and coal not becoming radioactive during irradiation, increase in the heating value, improvement in the caking property