On the Environmental and Economic Impact of Utility-Scale Renewable Energy Deployment

As per the U.S Energy Information Administration’s latest inventory of electricity generators, renewable energy, most notably solar and wind, will account for roughly 70% of nearly 40 gigawatts of new electricity generating capacity to start commercial operation in 2021. The year 2021 will also set a record in the deployment of utility-scale solar capacity by adding 15.4 gigawatts of capacity to the grid, which surpasses the 12 gigawatts increase in 2020. The rapid increase of renewable energy is expected to significantly decrease emissions of greenhouse gases and change the load profile in the power grid by suppressing production from conventional generators. This paper aims to propose a framework to study the impact of utility-scale solar PV deployment on the generation resource allocation and investigate the economics and policy of electricity generation and carbon emissions. The investigation is carried on the generation resource pool of the southeast region of the U.S augmented by a substantial amount of utility-scale solar generation

Capacity usage determination of a Capacitor-less D-STATCOM considering Power System Uncertainties

The increasing adoption of distributed energy resources (DERs), particularly solar generation and the use of unconventional loads such as plug-in electric vehicles (PHEVs), has a profound impact on the planning and operation of electric distribution systems. In particular, PHEV charging introduces stochastic peaks in energy consumption, while solar generation is fraught with variability during intermittent clouds. The stochastic nature of such DERs renders the operation of mechanical assets such as on-load tap changers and switched capacitor banks ineffective. A possible solution to mitigate the undesirable effects of DERs is using solid-state-based devices such as a distribution static synchronous compensator (D-STATCOM). This paper examines the capacity usage of a capacitor-less D-STATCOM in distribution systems while considering the uncertainties associated with using the aforementioned DERs. We propose a Monte Carlo simulation to study the capacity usage problem with DER inputs sampled from the proposed underlying distributions

On Accelerated Aging of Mechanical Assets in Distribution Systems with Renewable Generation

The integration challenges associated with the widespread adoption of the photovoltaic generation can be divided into operational and the maintenance issues. Work done in recent years has addressed issues like voltage rise and unbalance. Less attention was directed to the maintenance challenges like accelerated aging of mechanically controlled voltage support assets under rapidly changing conditions. In particular, there is need for analysis on the mechanism of accelerated wear and tear of devices such as on-load tap changers and capacitor banks exposed to rapid voltage fluctuations. Such an analysis relies on development of lifetime models of switching devices to study the impact of increased stress, whether electrical or mechanical, on operational life. This article focuses on developing such models and proposes the framework to study the impact of non-scheduled distributed generation on aging of mechanically-switched devices commonly used in distribution feeders

Impact of Physical Exercise on Gut Microbiome, Inflammation, and the Pathobiology of Metabolic Disorders.

The gastrointestinal tract (GIT) harbors a complex and diverse microbial composition that outnumbers our own body cells and their gene contents. These microbes play a significant role in host metabolism and energy homeostasis. Emerging evidence suggests that the GIT microbiome significantly contributes to host health and that impairments in the microbiome may cause the development of metabolic diseases. The microbiome architecture is shaped by several genetic and environmental factors, including nutrition and physical activity. Physical exercise has preventive or therapeutic effects in respiratory, cardiovascular, neuroendocrine, and muscular diseases. Yet, we still have little information of the beneficial effects of physical exercise on GIT health and microbial composition. Furthermore, we are not aware whether exercise-derived benefits on microbiome diversity can beneficially influence other tissues and body organs. The aim of this article is to review the available literature on exercise-induced microbiome changes and to explain how these changes may induce inflammatory, immune, and oxidative responses that may contribute to the improvement of metabolic disorders. A systemic and comprehensive search of the relevant literature using MEDLINE and Google Scholar databases was conducted during fall 2018 and spring 2019. The search identified sixty-two research and review articles that discussed exercise-induced microbiome changes. The review of the relevant literature suggests that exercise-induced microbial changes affect the host's immune pathways and improve energy homeostasis. Microbes release certain neuroendocrine and immune-modulatory factors that may lower inflammatory and oxidative stress and relieve patients suffering from metabolic disorders. Exercise-induced changes in microbial diversity are able to improve tissue metabolism, cardiorespiratory fitness, and insulin resistance

Perioperative hemodynamic effects of dexmedetomidine as an adjuvant to 0.2% ropivacaine in ultrasonography guided interscalene brachial plexus block for elective shoulder arthroscopic surgeries under general anaesthesia: a prospective observational study

Background: Although an increasing number of anesthesiologists are using peripheral nerve catheters for postoperative analgesia, single shot blocks are still more common. Ropivacaine has become the most commonly used long-acting local anesthetic, and the duration of analgesia has been estimated to be 8 to 14 hours.Methods: The study was conducted from February 2020 to October 2021 after obtaining approval from the institutional ethics committee. The study was a prospective observational study.Results: Hemodynamic changes in patients who received dexmedetomidine in combination with Ropivacaine had a favorable reduction in both heart rate and blood pressure without causing any major side effect. Comparison of postoperative MAP (mmHg) in two groups at various intervals of time was observed and found to be statistically significant (p value of <0.05). Comparison of postoperative heart rate (beats/min) among two groups at various intervals of time was statistically significant (p value of <0.05).Conclusions: We can conclude that preoperative inter-scalene block given reduces the analgesic requirement intraoperatively as well postoperatively. And the hemodynamic changes in patients who received dexmedetomidine in combination with ropivacaine had a favorable reduction in both heart rate and blood pressure without causing any major side effect.

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

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed

Study of hardness and microstructure of Fe-C-Si-Mn-B hardfacing alloy

Iron based alloys are normally utilized for abrasive coatings to resist wear. Chromium added iron alloys are commonly chosen for hardfacing, which is one of the surface improvement methods. Such alloys are costly and give a moderate hardness to the deposits, due to the large addition of chromium. Fe-C-Si-Mn alloys show hardness up to 450VHN, without heat treatment, which is an established fact. In this work boron is added to Fe-C-Si-Mn welding alloys, deposits are made on low carbon steel substrates and resultant hardness is found to be an average of 650VHN, which is equivalent to some of the chromium containing ferrous alloys. Boron addition to Fe-C-Si-Mn alloy causes it to harden further, such that it can be utilized to combat wear. A few alloys are produced with the addition of boron (< 0.02Wt %) and tested for hardness and microstructure. Fe-C-Si-Mn-B alloys produced in the form welding electrodes can be utilized for hardfacing purposes with specific industrial applications. Micrographs reveal the presence of lower bainite and tempered martensite

On Estimation of Equipment Failures in Electric Distribution Systems Using Bayesian Inference

This paper presents a new statistical parametric model to predict the times-to-failure of broad classes of identical devices such as on-load tap changers, switched capacitors, breakers, etc. A two-parameter Weibull distribution with scale parameter given by the inverse power law is employed to model the survivor functions and hazard rates of on-load tap changers. The resulting three-parameter distribution, referred to as IPL-Weibull, is flexible enough to assume right, left, and even symmetrical modal distribution. In this work, we propose an inferential method based on Bayes’ rule to derive the point estimates of model parameters from the past right-censored failure data. Using the Monte Carlo integration technique, it is possible to obtain such parameter estimates with high accuracy