Activating ZnO nanorods photoanodes in visible light by CdS surface sensitiser

Thin films of c-axis aligned uniform ZnO nanorods (NRs) were fabricated on to fluorine-doped tin oxide-coated soda lime glass substrate by a two-step chemical route. Thereafter ZnO NRs/CdS core shell structures were successfully synthesised by depositing CdS layer on top of vertically aligned ZnO NRs using less hazardous nanocrystal layer deposition technique. The presence of CdS in ZnO NRs/CdS core shell structures was confirmed by energy dispersive X-ray analysis. Examination of structure and morphology of the fabricated films by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) revealed that both films have one-dimensional hexagonal wurtzite structure. Optical properties evaluated from ultraviolet-visible and photoluminescence spectra demonstrated better photo response of ZnO NRs/CdS core shell structure with respect to bare ZnO NR structure. Optical to chemical conversion efficiency of ZnO NRs/CdS photoanode was found to be similar to 1.75 times higher than bare ZnO NRs photoanode in photo electrochemical water splitting under visible light

Nanostructured ZnO thin film with improved optical and electrochemical properties prepared by hydrothermal electrochemical deposition technique

Zinc oxide (ZnO) thin films were grown on fluorine-doped tin oxide coated glass substrate by the hydrothermal electrochemical deposition (HTED) route using slightly acidic aqueous zinc acetate solution at 80°C and were characterised by various techniques. The deposited films showed n-type behaviour with improved carrier concentration. The steady state photocurrent densities were found to be 0.4 mA/cm2(under UV irradiation) and 8 μA/cm 2(under visible light illumination) at zero bias potential. Significant improvement of optical, electrochemical and photoelectrochemical properties of deposited films could be achieved using HTED technique

Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation

Multi-technique photoelectron spectrometer for micro-area spectroscopy and imaging

In this note we present the new multipurpose photoelectron spectroscopy facility installed recently at the CSIR-Central Glass and Ceramic Research Institute, Kolkata. Apart from the possibility of performing conventional X-ray and ultraviolet photoemission spectroscopic measurements, this instrument is also equipped with the necessary sources facilitating the performance of macro- as well as micro-area spectroscopy at varying temperatures along with the possibility of X-ray beam-induced secondary electron and chemical state imaging. We present here the details of the instrument along with some experimental results from various samples assessing the system performance

Effect of mechanical milling on the structural and dielectric properties of BaTiO3 powders

Barium titanate (BaTiO3) is a well-known ferroelectric material and widely used in electronic industries for the multi-layer ceramic capacitor. In this reported work, commercially available tetragonal BaTiO3 (BT) powders were taken to study the size effect on the structural and dielectric properties of the BT ceramics during high-energy ball milling (0-110 h). The same perovskite when kept under a normal atmospheric condition after milling shows gradual increase of additional crystalline phase that occurred because of the absorption of atmospheric CO2 gas, which is characterised as orthorhombic BaCO3. The milled BT samples were characterised by X-ray diffraction and small-angle X-ray scattering and a dielectric analyser. The purpose of this work was to study how the dielectric property of nanoBT ceramics varies with reduction of particle size, structural changes and the absorption of carbon by these nanopowders. It was observed that the dielectric constant of the BT powders increases with particle size reduction during milling. The dielectric behaviour of the BT ceramics significantly changes with polymorphic phase transformation in nanocrystalline BT at different stages of milling. The capacitance of nanoBT powders is significantly changed with the absorption of carbon by the nanoBT powders in a humid atmosphere

Fibre Bragg grating strain sensor and study of its packaging material for use in critical analysis on steel structure

Strain studies in civil structures, aircrafts, oil pipelines, etc. are pivotal in avoiding unexpected failures. Long-term strain study of structures also helps in setting the design limits of similar structures. Conventionally, most structures rely on maintenance schedules, visual inspection and a few conventional sensors. But the high cost of maintenance, lack of precision in visual inspection and susceptibility of sensors to harsh environmental conditions have made structural health monitoring (SHM) a necessity. Over the past few decades. fibre Bragg grating (FBG) sensors have emerged as a suitable, accurate and cost-effective tool in SHM. Fibre Bragg gratings are obtained by creating periodic variations in the refractive index of the core of an optical fibre. These periodic variations are created by using powerful ultraviolet radiation from a laser source. Periodic structure acts as a Bragg reflector of particular wavelength. Minute change in the periodic structure due to external perturbation will cause appreciable wavelength shift. This shift in turn can be translated to measurand related to perturbation. The main advantages of FBGs over other optical sensor schemes are its low cost, good linearity, wavelength multiplexing capacity, resistance in harsh environments and absolute measurement. FBG sensor technology is now on the verge of maturity after almost two decades of active research and development in this field. Efforts are now concentrating on delivering complete FBG sensor systems including front-end electronics. This paper demonstrates with the aim to provide different design and experimental packaging procedures of indigenously developed FBG sensors for strain measurement. Various model of loading on FBG have been tried to explore with particular attention on the primary packaging of the sensor for application on steel cantilever structure and cement concrete. Preliminary packaging has been done with composite materials such as epoxy resin casting and fibre reinforced plastic (FRP) composites. Encouraging results are obtained and presented in this paper. The results are compared with the standard FBG sensors and with mechanical strain gauge. (C) 2009 Elsevier B.V. All rights reserved

Fibre Bragg grating strain sensor and study of its packaging material for use in critical analysis on steel structure

Strain studies in civil structures, aircrafts, oil pipelines, etc. are pivotal in avoiding unexpected failures. Long-term strain study of structures also helps in setting the design limits of similar structures. Conventionally, most structures rely on maintenance schedules, visual inspection and a few conventional sensors. But the high cost of maintenance, lack of precision in visual inspection and susceptibility of sensors to harsh environmental conditions have made structural health monitoring (SHM) a necessity. Over the past few decades. fibre Bragg grating (FBG) sensors have emerged as a suitable, accurate and cost-effective tool in SHM. Fibre Bragg gratings are obtained by creating periodic variations in the refractive index of the core of an optical fibre. These periodic variations are created by using powerful ultraviolet radiation from a laser source. Periodic structure acts as a Bragg reflector of particular wavelength. Minute change in the periodic structure due to external perturbation will cause appreciable wavelength shift. This shift in turn can be translated to measurand related to perturbation. The main advantages of FBGs over other optical sensor schemes are its low cost, good linearity, wavelength multiplexing capacity, resistance in harsh environments and absolute measurement. FBG sensor technology is now on the verge of maturity after almost two decades of active research and development in this field. Efforts are now concentrating on delivering complete FBG sensor systems including front-end electronics. This paper demonstrates with the aim to provide different design and experimental packaging procedures of indigenously developed FBG sensors for strain measurement. Various model of loading on FBG have been tried to explore with particular attention on the primary packaging of the sensor for application on steel cantilever structure and cement concrete. Preliminary packaging has been done with composite materials such as epoxy resin casting and fibre reinforced plastic (FRP) composites. Encouraging results are obtained and presented in this paper. The results are compared with the standard FBG sensors and with mechanical strain gauge. (C) 2009 Elsevier B.V. All rights reserved

Fibre Bragg gratings in structural health monitoring - Present status and applications

In-service structural health monitoring (SHM) of engineering Structures has assumed a significant role ill assessing their safety and integrity. Fibre Bragg grating (FBG) sensors have emerged as a reliable. in situ, non-destructive tool for monitoring, diagnostics and control ill Civil Structures. The versatility of FBG sensors represents a key advantage over other technologies ill the structural sensing field. In this article, the recent research and development activities in structural health monitoring using FBG sensors have been critically reviewed, highlighting the areas where further work is needed. A few packaging schemes for FBG strain sensors are also discussed. Finally a few limitations and market barriers associated with the use of these sensors have been addressed. (C) 2008 Elsevier B.V. All rights reserved

Effects of Mg% on open circuit voltage and short circuit current density of Zn1-xMgxO/Cu2O heterojunction thin film solar cells, processed using electrochemical deposition and spin coating

Zn1-xMgxO/Cu2O/Ag solar cells were fabricated upon fluorine doped tin oxide coated soda lime glass substrate with varying percentage of Mg mol% doping in zinc oxide (ZnO) layer. Short circuit current density & open circuit voltages of the fabricated cells were investigated. Optimum doping with Mg improved the transparency of ZnO layer which helped in increasing the short circuit current density of solar cells. An enhancement of open circuit voltage was observed with increase in x, which was investigated using X-ray photoelectron spectroscopy and the results revealed that with increase in x, there was a decrease in conduction band offset between Zn1-xMgxO and cuprous oxide layers. From UV-Visible transmittance spectra, it was observed that with Mg doping in ZnO nanostructure, optical losses were reduced which resulted in increase in Short circuit current density. The objective of this study was to investigate and develop a technology for fabrication of solar cells that is both cost effective and easy to produce