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Abstract Although much is known about the environmental conditions necessary for tornadogenesis, the near-ground vorticity dynamics during the tornadogenesis process itself are still somewhat poorly understood. For instance, seemingly contradicting mechanisms responsible for large near-ground vertical vorticity can be found in the literature. Broadly, these mechanisms can be sorted into two classes, one being based on upward tilting of mainly baroclinically produced horizontal vorticity in descending air (here called downdraft mechanism), while in the other the horizontal vorticity vector is abruptly tilted upward practically at the surface by a strong updraft gradient (referred to as in-and-up mechanism). In this study, full-physics supercell simulations and highly idealized simulations show that both mechanisms play important roles during tornadogenesis. Pretornadic vertical vorticity maxima are generated via the downdraft mechanism, while the dynamics of a fully developed vortex are dominated by the in-and-up mechanism. Consequently, a transition between the two mechanisms occurs during tornadogenesis. This transition is a result of axisymmetrization of the pretornadic vortex patch and intensification via vertical stretching. These processes facilitate the development of the corner flow, which enables production of vertical vorticity by upward tilting of horizontal vorticity practically at the surface, i.e. the in-and-up mechanism. The transition of mechanisms found here suggests that early stages of tornado formation rely on the downdraft mechanism, which is often limited to a small vertical component of baroclinically generated vorticity. Subsequently, a larger supply of horizontal vorticity (produced baroclinically or via surface drag, or even imported from the environment) may be utilized, which marks a considerable change in the vortex dynamics.


2021 ◽  
Author(s):  
◽  
Daniel Wilson

<p>New Zealand’s electricity sector has undergone considerable change in the three decades to 2015. Those changes are part of a broader shift within the political landscape, from state intervention to market dominance and the view of individuals as consumers. An ill-fated policy proposal in 2013 called NZ Power sought to reduce electricity prices, and implement structural reform that would reverse decades of change within the sector.  This thesis examines the context in which the reforms to the sector occurred so as to understand better why some policies are successfully implemented and other proposals fail. Specifically, this thesis examines the triumvirate of principal goals the sector has sought to achieve, and the political discourse around them: security of supply, economically efficient prices, and minimising environmental damage. From these insights, a framework is constructed against which future policies can be assessed as to the likelihood of their successful implementation.</p>


2021 ◽  
Author(s):  
◽  
Daniel Wilson

<p>New Zealand’s electricity sector has undergone considerable change in the three decades to 2015. Those changes are part of a broader shift within the political landscape, from state intervention to market dominance and the view of individuals as consumers. An ill-fated policy proposal in 2013 called NZ Power sought to reduce electricity prices, and implement structural reform that would reverse decades of change within the sector.  This thesis examines the context in which the reforms to the sector occurred so as to understand better why some policies are successfully implemented and other proposals fail. Specifically, this thesis examines the triumvirate of principal goals the sector has sought to achieve, and the political discourse around them: security of supply, economically efficient prices, and minimising environmental damage. From these insights, a framework is constructed against which future policies can be assessed as to the likelihood of their successful implementation.</p>


2021 ◽  
Vol 850 (1) ◽  
pp. 012022
Author(s):  
K Sowndarya ◽  
S Monica ◽  
M S Abhisheka ◽  
A K Pradikshan ◽  
M Venkatesan

Abstract Micromixers are used for mixing of multiphase fluids in microchannels. Passive micromixers help in mixing of fluids by having a designed periphery in their structure. In the current study, a Y micro-channel section of 25 mm length with an inlet diameter of 2 mm is considered. Vane shaped micromixers are placed inside the channel to mix fluids of two different concentrations. The vanes are positioned at specific places inside the channel to enhance mixing in the stratified flow stream. The presence of vanes during the flow induces mixing of the stratified fluids without requiring additional components. The study is carried out using COMSOL Multiphysics. The mixing index increases with increase in the number of vanes and no considerable change in velocity is observed downstream of the last vane. Further, when the thickness of the vane is increased, it is found that the mixing index also increases.


Author(s):  
Hilary Tompsett

Olive Stevenson (1930–2013) was an internationally recognized social work practitioner, educator, scholar, public servant, and consultant. She is particularly remembered for her contribution to the Maria Colwell Enquiry Report in 1974, which investigated a child’s death at the hands of her stepfather. The report was the first of what later became known as Serious Case Reviews. Stevenson authored a minority report, expressing dissent from some of the main report’s conclusions and strongly supporting social workers. This was much appreciated by practitioner social workers and leaders of Social Service departments at the time. She is also regarded by many in the United Kingdom as the leading social work academic of her generation over a 50-year career during a period of considerable change and challenge for the social work profession.


2021 ◽  
Vol 11 (5) ◽  
pp. 143-148
Author(s):  
Shubham Gandhi ◽  
Drumil Newaskar ◽  
Rohan Apte ◽  
Preet Aligave

Lithium is one of the foremost valuable metal which is widely used for manufacturing batteries and also has other uses in solar panels, ceramics, glasses and pharmaceuticals. Lithium is third most abundant element after hydrogen and helium but the most lithium deposits are only in Bolivia (21 million tons), Argentina (17 million tons), Chile (9 million tons), Australia (6.8 million tons), China (4.5 million tons). Bolivia, Argentina, Chile forms so called lithium triangle. Due to depleting reserves of fossil fuels and its harmful impact on the environment has forced the globe to shift to Lithium-ion batteries which is much eco-friendlier alternative. India’s push for electric vehicles (EV) may cause a considerable change in its energy security priorities, with securing lithium supplies, a key material for creating batteries, becoming as important as buying oil and gas fields overseas. India doesn't have enough lithium reserves for manufacturing lithium-ion batteries. The majority electric vehicles within the country run on imported batteries, mostly from China. At present a lithium-ion battery accounts for 40% of the overall cost of an electrical vehicle. Khanij Bidesh Pvt Ltd is a venture firm of three central public sector enterprises namely National Aluminum Company (Nalco), Hindustan Copper Ltd (HCL), Mineral Exploration Company Ltd (MECL). The KABIL would do identification, acquisition, exploration, development, mining and processing of strategic minerals overseas for commercial use and meeting country’s requirement of those minerals. The mission is to not allow India to fall in a very vulnerable position with a probable threat of supply squeeze as went on within the case of petroleum, with India being the world’s third largest oil importer and to amass cobalt and lithium mines in addition on get into purchase agreements of those minerals. This may help in achieving resource security with regard to strategic minerals.


Author(s):  
V. I. Pleshchenko

The intention to preserve a comfort habitat for the mankind finds expression in the attempts to decrease the anthropogenic impact on the environment. A concept “carbon footprint” appeared, which reflects input of some kind of activity to the environment pollution. The desire to influence producers’ behavior and make them decrease their carbon footprint under existing conditions results in elaboration new kinds of taxes and duties, stimulating modernization of technological process and decrease of harmful substances emissions. It is expected that in case of the taxes being implemented by big metal products consumers, such as Western Europe, will result in considerable change of the metal products market. An analysis of various ways of metal producers’ adaptation to operation in conditions of the expected changes presented. It was shown that such organization measures as lobbying of interests and artificial differentiation of business on provisionally “clean” and “dirty” will result in a rather restricted result. Thereupon actuality of a radical modernization of production capacities to decarbonize the technologies of steel production grows. Replacement of the carbon by hydrogen for reducing of iron oxides is the most advanced technological solution. At the same time, the hydrogen metallurgy is not yet implemented anywhere on industrial scale, and the hydrogen application in the production cycle results in a lot of questions, having not yet definite answers. A SWOT-analysis presented, demonstrating advantages and disadvantages of hydrogen technology mastering by metals producers.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
K. P. Shinde ◽  
E. J. Lee ◽  
M. Manawan ◽  
A. Lee ◽  
S.-Y. Park ◽  
...  

AbstractThe crystal structure, cryogenic magnetic properties, and magnetocaloric performance of double perovskite Eu2NiMnO6 (ENMO), Gd2NiMnO6 (GNMO), and Tb2NiMnO6 (TNMO) ceramic powder samples synthesized by solid-state method have been investigated. X-ray diffraction structural investigation reveal that all compounds crystallize in the monoclinic structure with a P21/n space group. A ferromagnetic to paramagnetic (FM-PM) second-order phase transition occurred in ENMO, GNMO, and TNMO at 143, 130, and 112 K, respectively. Maximum magnetic entropy changes and relative cooling power with a 5 T applied magnetic field are determined to be 3.2, 3.8, 3.5 J/kgK and 150, 182, 176 J/kg for the investigated samples, respectively. The change in structural, magnetic, and magnetocaloric effect attributed to the superexchange mechanism of Ni2+–O–Mn3+ and Ni2+–O–Mn4+. The various atomic sizes of Eu, Gd, and Tb affect the ratio of Mn4+/Mn3+, which is responsible for the considerable change in properties of double perovskite.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Sercan Ö. Arık ◽  
Joel Shor ◽  
Rajarishi Sinha ◽  
Jinsung Yoon ◽  
Joseph R. Ledsam ◽  
...  

AbstractThe COVID-19 pandemic has highlighted the global need for reliable models of disease spread. We propose an AI-augmented forecast modeling framework that provides daily predictions of the expected number of confirmed COVID-19 deaths, cases, and hospitalizations during the following 4 weeks. We present an international, prospective evaluation of our models’ performance across all states and counties in the USA and prefectures in Japan. Nationally, incident mean absolute percentage error (MAPE) for predicting COVID-19 associated deaths during prospective deployment remained consistently <8% (US) and <29% (Japan), while cumulative MAPE remained <2% (US) and <10% (Japan). We show that our models perform well even during periods of considerable change in population behavior, and are robust to demographic differences across different geographic locations. We further demonstrate that our framework provides meaningful explanatory insights with the models accurately adapting to local and national policy interventions. Our framework enables counterfactual simulations, which indicate continuing Non-Pharmaceutical Interventions alongside vaccinations is essential for faster recovery from the pandemic, delaying the application of interventions has a detrimental effect, and allow exploration of the consequences of different vaccination strategies. The COVID-19 pandemic remains a global emergency. In the face of substantial challenges ahead, the approach presented here has the potential to inform critical decisions.


2021 ◽  
Vol 13 (3) ◽  
pp. 56-72
Author(s):  
Beata Gavurova ◽  
Andrej Privara ◽  
Jana Janikova ◽  
Viliam Kovac

The paper investigates the relations of the macroeconomic indicators related to the competitiveness of the tourism sector among the explored countries. The tourism sector plays an important role with the purpose of contributing to the economy of each country and, thus, its competitiveness among the other countries. The fundamental aim of the paper is to investigate the relations between the macroeconomic indicators related to tourism and their influence on the economy of the countries. The data set comprises the eight macroeconomic indicators, of which the four ones are related to the gross domestic product, the two ones to employment, the penultimate one to investment, and the last one to expenditure. The observed period covers the years 1995 to 2019. The Euclidean distance is employed to evaluate the similarity of the countries and the cluster analysis to group them successively. There are several patterns visible in the analysis outcome. Firstly, the countries that behave differently for both groups of the indicators with Mexico at the top position. Secondly, the countries with considerable change throughout the observed period where Greece stands at the most extreme position for the gross domestic product indicators and Hungary in the case of the other economic indicators. Thirdly, Chile remains at the evenest position throughout the whole explored period for the first group of the indicators and the United States for the second group of the indicators. Finally, Australia has almost the same development for both groups at the evenest tendency.


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