Embedding initial data for black hole collisions

We discuss isometric embedding diagrams for the visualization of initial data for the problem of the head-on collision of two black holes. The problem of constructing the embedding diagrams is explicitly presented for the best studied initial data, the Misner geometry. We present a partial solution of the embedding diagrams and discuss issues related to completing the solution.Comment: (27pp text, 11 figures

The politics of alcohol policy in Nigeria: a critical analysis of how and why brewers use strategic ambiguity to supplant policy initiatives

The global call by the World Health Assembly (WHA) to control the rising alcohol-related problems caused by harmful consumption through policy became necessary in 2005 due to the recognition of the fact that many countries did not have alcohol policies. This gave rise to the adoption of a ten-point policy strategy by the World Health Organization (WHO) Member States in 2010. Against this backdrop, many countries adopted alcohol policies to reduce harmful alcohol consumption. Nigeria was one of the WHO Member Countries that adopted the resolution. Nigeria is among the 30 countries with the highest per capita consumption and alcohol-related problems, yet has not formulated alcohol policy to date. This paper draws on Eisenberg’s Strategic Ambiguity Model to explore the role of brewers in supplanting alcohol policy initiatives in Nigeria. It argues that the leading alcohol producers in Nigeria have been the main reason alcohol policies have not been formulated. The article focuses on why their campaigns for responsible drinking, promotions, sponsorships and ‘strategic social responsibilities’ may have increased since the WHA made the call and the WHO adopted the resolution in 2010. It concludes by arguing that there is an urgent need to formulate policies drawing from the WHO resolution to curtail the activities of these brewers and reduce harmful consumption

Defects and boundary layers in non-Euclidean plates

We investigate the behavior of non-Euclidean plates with constant negative Gaussian curvature using the F\"oppl-von K\'arm\'an reduced theory of elasticity. Motivated by recent experimental results, we focus on annuli with a periodic profile. We prove rigorous upper and lower bounds for the elastic energy that scales like the thickness squared. In particular we show that are only two types of global minimizers -- deformations that remain flat and saddle shaped deformations with isolated regions of stretching near the edge of the annulus. We also show that there exist local minimizers with a periodic profile that have additional boundary layers near their lines of inflection. These additional boundary layers are a new phenomenon in thin elastic sheets and are necessary to regularize jump discontinuities in the azimuthal curvature across lines of inflection. We rigorously derive scaling laws for the width of these boundary layers as a function of the thickness of the sheet

Anodic aluminum oxide formed in aqueous solutions of chelated complex zinc and cobalt compounds

The galvanostatic anodizing results of specially prepared high-purity aluminum in aqueous solutions of complex compounds K3[Co(C2O4)3] and K2[Zn(edta)] of various concentrations in the current density ranges 1.5−1.10 · 102 and 1.5−30 mA · cm−2, respectively. The kinetic features of anodizing have been established, indicating the occurrence of an oscillatory electrochemical process. Morphological features of a flaky and loose nature for K2[Zn(edta)] and monolithic for K3[Co(C2O4)3], uncharacteristic for anodic aluminum oxide, were revealed. The elemental composition, IR spectroscopic and photoluminescent characteristics of the formed oxides are shown

Aluminum anodization in deionized water as electrolyte

Thin oxide films were prepared electrochemically on the aluminum surface using the high-voltage discharge and potentiostatic methods in deionized water as an electrolyte. The growth of continuous films occurred only at potentials lower than the breakdown potential. The films obtained by the discharge method are more uniform and can grow to a higher thickness in comparison to those formed by the potentiostatic mode, as demonstrated by electrochemical impedance spectroscopy (EIS), transmission electron microscopy (TEM), and scanning Kelvin probe force microscopy (SKPFM). The data herein obtained can be used as a reference to understand better the properties of the films produced in conventional electrolytes where apart from water other species are present

Adaptive Estimation for Uncertain Nonlinear Systems with Measurement Noise: A Sliding-Mode Observer Approach

International audienceThis paper deals with the problem of adaptive estimation, i.e. the simultaneous estimation of the state and time-varying parameters, in the presence of measurement noise and state disturbances, for a class of uncertain nonlinear systems. An adap-tive observer is proposed based on a nonlinear time-varying parameter identification algorithm and a sliding-mode observer. The nonlinear time-varying parameter identification algorithm provides a fixed-time rate of convergence, to a neighborhood of the origin, while the sliding-mode observer ensures ultimate boundedness for the state estimation error attenuating the effects of the external disturbances. Linear matrix inequalities are provided for the synthesis of the adaptive observer while the convergence proofs are given based on the Lyapunov and Input-to-State Stability theory. Finally, some simulation results show the feasibility of the proposed approach

ФОРМИРОВАНИЕ ПОРИСТОГО АНОДНОГО ОКСИДА АЛЮМИНИЯ В РАСТВОРЕ МАЛОНОВОЙ КИСЛОТЫ С ДОБАВКОЙ АРСЕНАЗО I: 1. КИНЕТИКА АНОДИРОВАНИЯ, ОБЪЕМНЫЙ РОСТ, РАСТВОРЕНИЕ И МЕЗОПОРИСТАЯ СТРУКТУРА ОКСИДА

A formation of anodic alumina in malonic acid containing complexing additives arsezano I and without it,the kinetics of the formation of alumina, mesoporous structure, Pilling-Bedworth ratio and solution study.Проведено гальваностатическое формирование анодного оксида алюминия в малоновой кислоте с комплексообразующей добавкой арсеназо I и без нее. Изучены кинетика формирования оксида, растворение алюминия в процессе анодирования, объемный рост анодного оксида алюминия и его мезопористая структура

The global proportion and volume of unrecorded alcohol in 2015.

Alcohol consumption is associated with elevated risks of disease and injury, and the best indicator of the level of consumption in a country is total alcohol per capita (APC) consumption among adults which comprises recorded consumption and unrecorded consumption. While recorded consumption can be assessed with small measurement bias via taxation or other governmental records, unrecorded consumption is more difficult to assess. The objectives of this study were to estimate the country-specific proportion and volume of unrecorded APC in 2015, to identify main sources of unrecorded alcohol and to assess to what extent experts perceive unrecorded alcohol as a public health, social, and financial problem. Estimates of unrecorded APC were based on a multilevel fractional response regression model using data from World Health Organization's (WHO) STEPwise approach to surveillance surveys (16 countries, 66 188 participants), estimates from the routine WHO reporting on key indicators of alcohol use (189 countries), and a nominal group expert assessment (42 countries, 129 experts). Expert assessments also included data on the sources of unrecorded alcohol and the perception of unrecorded alcohol as a public health, social, and financial problem. The volume of global unrecorded APC was 1.6 L pure alcohol, representing 25% of the total APC. The volume of unrecorded APC was highest in Europe (2.1 L per capita), while the proportion of unrecorded APC was highest in the WHO Eastern Mediterranean region (57% of the total alcohol). In countries with available data, homemade alcohol was identified as a major source of unrecorded alcohol. The majority of experts considered unrecorded alcohol to be a public health (62%), social (60%), and financial problem (54%). High volumes of unrecorded alcohol are consumed globally; however, the volumes consumed and the sources of the unrecorded alcohol exhibit large geographical variation