Membrane Based Point-of-Use Drinking Water Treatment Systems

Membrane based PoU water treatment systems are preferred due to shortcomings of other water treatment technologies. This system works without the addition of chemicals, with relatively low energy consumption, and easy and well-arranged process conductions. Hence, there is an inevitable need to understand the basic operational parameters, design and maintenance of membrane based PoU water treatment systems. The book provides insight of membrane based PoU water treatment systems (ultrafiltration, microfiltration, nano-filtration, reverse osmosis etc.) including description of physical, chemical, microbiological water contaminants and conventional methods for their removal. This book also discusses the limitations of conventional water treatment systems in fulfilling PoU water demands in developing countries and evaluates the suitability of membrane based treatment covering design, operation, maintenance and techno-economic feasibility of PoU water treatment system. The book covers issues related to water quality, water contamination, reasons for recent water quality degradation, conventional methods for water treatment –their limitations and need for PoU water treatment systems. The first chapter explains the contaminants in drinking water, sources and effects of these contaminants, and importance of removal of these contaminants. Second chapter describes various units, advantages and limitations of conventional water treatment plant in addition to various point-of-use water treatment technologies. Third chapter covers detail about ultrafiltration, microfiltration, nanofiltration and RO based PoU water treatment systems. Fourth chapter describes design criteria, and design of pre-treatment and post-treatment and multi-stage/multi-barrier systems. Modelling and simulation, process optimization, material requirement and bill of materials and more importantly fabrication aspects are included in Chapter 5. Chapter 6 includes operation and maintenance aspects including that of pre and post treatment units. Techno-economic aspects of membrane based PoU systems are elucidated in seventh chapter. The last chapter elaborates process of certification and evaluation

Secrecy Performance of Cooperative Cognitive AF Relaying Networks With Direct Links Over Mixed Rayleigh and Double-Rayleigh Fading Channels

This paper investigates the secrecy performance of an underlay cooperative cognitive relaying network, wherein a secondary source vehicle communicates with a fixed secondary destination terminal via a direct link and with the assistance of a secondary amplify-and-forward relay vehicle in the presence of a passive secondary eavesdropper vehicle, taking into consideration of interference at the primary user. We assume that the eavesdropper vehicle takes the advantages of both the relay link and direct link. We consider that vehicle-to-vehicle links are modeled as double-Rayleigh fading, while vehicle-to-fixed infrastructure links are modeled as Rayleigh fading. Such a scenario finds it relevancy in vehicle-to-vehicle communication and/or vehicle-to-infrastructure communication under spectrum sharing heterogeneous cooperative vehicular networks. For such a realistic scenario, in particular, we derive a tight lower bound expression of the secrecy outage probability under mixed Rayleigh and double-Rayleigh fading channels. We also present an effective secrecy diversity order analysis and show that the considered system can achieve a secrecy diversity order of 2 for infinitely large average channel gain values of the main links. Finally, we demonstrate the accuracy of our analytical findings via numerical and simulation results and show the impact of channel conditions, primary interference constraints, and direct links on the secrecy performance of the considered syste

Healthcare Access and Quality Index based on mortality from causes amenable to personal health care in 195 countries and territories, 1990–2015: a novel analysis from the Global Burden of Disease Study 2015

Background National levels of personal health-care access and quality can be approximated by measuring mortality rates from causes that should not be fatal in the presence of effective medical care (ie, amenable mortality). Previous analyses of mortality amenable to health care only focused on high-income countries and faced several methodological challenges. In the present analysis, we use the highly standardised cause of death and risk factor estimates generated through the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) to improve and expand the quantification of personal health-care access and quality for 195 countries and territories from 1990 to 2015. Methods We mapped the most widely used list of causes amenable to personal health care developed by Nolte and McKee to 32 GBD causes. We accounted for variations in cause of death certification and misclassifications through the extensive data standardisation processes and redistribution algorithms developed for GBD. To isolate the effects of personal health-care access and quality, we risk-standardised cause-specific mortality rates for each geography-year by removing the joint effects of local environmental and behavioural risks, and adding back the global levels of risk exposure as estimated for GBD 2015. We employed principal component analysis to create a single, interpretable summary measure-the Healthcare Quality and Access (HAQ) Index-on a scale of 0 to 100. The HAQ Index showed strong convergence validity as compared with other health-system indicators, including health expenditure per capita (r= 0.88), an index of 11 universal health coverage interventions (r= 0.83), and human resources for health per 1000 (r= 0.77). We used free disposal hull analysis with bootstrapping to produce a frontier based on the relationship between the HAQ Index and the Socio-demographic Index (SDI), a measure of overall development consisting of income per capita, average years of education, and total fertility rates. This frontier allowed us to better quantify the maximum levels of personal health-care access and quality achieved across the development spectrum, and pinpoint geographies where gaps between observed and potential levels have narrowed or widened over time. Findings Between 1990 and 2015, nearly all countries and territories saw their HAQ Index values improve; nonetheless, the difference between the highest and lowest observed HAQ Index was larger in 2015 than in 1990, ranging from 28.6 to 94.6. Of 195 geographies, 167 had statistically significant increases in HAQ Index levels since 1990, with South Korea, Turkey, Peru, China, and the Maldives recording among the largest gains by 2015. Performance on the HAQ Index and individual causes showed distinct patterns by region and level of development, yet substantial heterogeneities emerged for several causes, including cancers in highest-SDI countries; chronic kidney disease, diabetes, diarrhoeal diseases, and lower respiratory infections among middle-SDI countries; and measles and tetanus among lowest-SDI countries. While the global HAQ Index average rose from 40.7 (95% uncertainty interval, 39.0-42.8) in 1990 to 53.7 (52.2-55.4) in 2015, far less progress occurred in narrowing the gap between observed HAQ Index values and maximum levels achieved; at the global level, the difference between the observed and frontier HAQ Index only decreased from 21.2 in 1990 to 20.1 in 2015. If every country and territory had achieved the highest observed HAQ Index by their corresponding level of SDI, the global average would have been 73.8 in 2015. Several countries, particularly in eastern and western sub-Saharan Africa, reached HAQ Index values similar to or beyond their development levels, whereas others, namely in southern sub-Saharan Africa, the Middle East, and south Asia, lagged behind what geographies of similar development attained between 1990 and 2015. Interpretation This novel extension of the GBD Study shows the untapped potential for personal health-care access and quality improvement across the development spectrum. Amid substantive advances in personal health care at the national level, heterogeneous patterns for individual causes in given countries or territories suggest that few places have consistently achieved optimal health-care access and quality across health-system functions and therapeutic areas. This is especially evident in middle-SDI countries, many of which have recently undergone or are currently experiencing epidemiological transitions. The HAQ Index, if paired with other measures of health-systemcharacteristics such as intervention coverage, could provide a robust avenue for tracking progress on universal health coverage and identifying local priorities for strengthening personal health-care quality and access throughout the world.Bill & Melinda Gates Foundation.Peer Reviewe

SARAH-CONUS: Sub-weekly Area of Reservoirs from Analysis of Harmonized Landsat and Sentinel-2 data for Continental US

Surface area values for over 1,900 reservoirs in the Continental United States (CONUS) for the period of 2016-2023

Effects of sediment clustering on flow resistance in steep coarse-bed streams

&amp;lt;p&amp;gt;The flow velocity and discharge estimation are important in fluvial geomorphology and other wide variety of scientific purposes in river research applications. However, in steep coarse-bed streams dominated by large sediments and irregular channel beds, the conventional equations fail to consider the additional losses, leading to the overestimation of flow velocity. In such cases, the science of flow resistance, particularly during low relative submergence (y/D&amp;lt;sub&amp;gt;84&amp;lt;/sub&amp;gt;), and active transport conditions, needs to be revisited. Since the poorly sorted sediments on the channel bed also increases the resistance in the flow (Yadav et al., 2021). This work examined the effects of geometric standard deviation (&amp;amp;#963;&amp;lt;sub&amp;gt;g&amp;lt;/sub&amp;gt;) of the bed material on flow resistance in steep streams using the dataset reported in the literature and conventional flow resistance equations. The flow resistance estimates in poorly sorted sediments were observed to be unreliable for the non-uniformity () range 7.5-10 for all the equations, however relatively better flow velocity estimates were observed for &amp;amp;#963;&amp;lt;sub&amp;gt;g &amp;lt;/sub&amp;gt;greater than 10. This distinct response of flow resistance equations for &amp;amp;#963;&amp;lt;sub&amp;gt;g&amp;lt;/sub&amp;gt; ranging between 7 to 10 was probably due to additional losses occurring due to armouring and formation of sediment clusters and reticulate structures in this subset of the data. The dimensionless shear stress (&amp;lt;em&amp;gt;&amp;amp;#964;*&amp;lt;/em&amp;gt;) exerted on the channel bed for the dataset with &amp;amp;#963;&amp;lt;sub&amp;gt;g&amp;lt;/sub&amp;gt; between 7.5 to 10 was in agreement to develop sediment clusters as suggested by various researchers. Furthermore, when the geometric standard deviation exceeds 10, the unbiased flow velocity estimates using the conventional flow resistance equations indicate the reduced resistance in the flow field. This behaviour may be attributed to the smoothing of bed or change in bed conditions either due to disintegration of bedforms and sediment clusters at higher discharge or structural instability.&amp;amp;#160;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;&amp;lt;strong&amp;gt;Keywords- &amp;lt;/strong&amp;gt;Flow resistance, sediment sorting, non-uniformity, sediment clusters, armouring, shear stress&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;&amp;amp;#160;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;&amp;lt;strong&amp;gt;Yadav, A., Sen, S.&amp;lt;sup&amp;gt;&amp;lt;/sup&amp;gt;, Mao, L., &amp;amp; Schwanghart&amp;lt;sup&amp;gt;&amp;lt;/sup&amp;gt;W. (2021), &amp;lt;/strong&amp;gt;Evaluation of flow resistance equations for high gradient rivers using geometric standard deviation of bed material&amp;lt;strong&amp;gt;, &amp;lt;/strong&amp;gt;&amp;lt;em&amp;gt;Journal of Hydrology (accepted)&amp;lt;/em&amp;gt;&amp;lt;/p&amp;gt;</jats:p