Hydrogen Absorption Properties of Metal-Ethylene Complexes

Recently, we have predicted [Phys. Rev. Lett. 97, 226102 (2006)] that a single ethylene molecule can form stable complexes with light transition metals (TM) such as Ti and the resulting TMn-ethylene complex can absorb up to ~12 and 14 wt % hydrogen for n=1 and 2, respectively. Here we extend this study to include a large number of other metals and different isomeric structures. We obtained interesting results for light metals such as Li. The ethylene molecule is able to complex with two Li atoms with a binding energy of 0.7 eV/Li which then binds up to two H2 molecules per Li with a binding energy of 0.24 eV/H2 and absorption capacity of 16 wt %, a record high value reported so far. The stability of the proposed metal-ethylene complexes was tested by extensive calculations such as normal-mode analysis, finite temperature first-principles molecular dynamics (MD) simulations, and reaction path calculations. The phonon and MD simulations indicate that the proposed structures are stable up to 500 K. The reaction path calculations indicate about 1 eV activation barrier for the TM2-ethylene complex to transform into a possible lower energy configuration where the ethylene molecule is dissociated. Importantly, no matter which isometric configuration the TM2-ethylene complex possesses, the TM atoms are able to bind multiple hydrogen molecules with suitable binding energy for room temperature storage. These results suggest that co-deposition of ethylene with a suitable precursor of TM or Li into nanopores of light-weight host materials may be a very promising route to discovering new materials with high-capacity hydrogen absorption properties

The Economic Resource Receipt of New Mothers

U.S. federal policies do not provide a universal social safety net of economic support for women during pregnancy or the immediate postpartum period but assume that employment and/or marriage will protect families from poverty. Yet even mothers with considerable human and marital capital may experience disruptions in employment, earnings, and family socioeconomic status postbirth. We use the National Survey of Families and Households to examine the economic resources that mothers with children ages 2 and younger receive postbirth, including employment, spouses, extended family and social network support, and public assistance. Results show that many new mothers receive resources postbirth. Marriage or postbirth employment does not protect new mothers and their families from poverty, but education, race, and the receipt of economic supports from social networks do

DFT Study of Planar Boron Sheets: A New Template for Hydrogen Storage

We study the hydrogen storage properties of planar boron sheets and compare them to those of graphene. The binding of molecular hydrogen to the boron sheet (0.05 eV) is stronger than that to graphene. We find that dispersion of alkali metal (AM = Li, Na, and K) atoms onto the boron sheet markedly increases hydrogen binding energies and storage capacities. The unique structure of the boron sheet presents a template for creating a stable lattice of strongly bonded metal atoms with a large nearest neighbor distance. In contrast, AM atoms dispersed on graphene tend to cluster to form a bulk metal. In particular the boron-Li system is found to be a good candidate for hydrogen storage purposes. In the fully loaded case this compound can contain up to 10.7 wt. % molecular hydrogen with an average binding energy of 0.15 eV/H2.Comment: 19 pages, 7 figures, and 3 table

Fertility, Living Arrangements, Care and Mobility

There are four main interconnecting themes around which the contributions in this book are based. This introductory chapter aims to establish the broad context for the chapters that follow by discussing each of the themes. It does so by setting these themes within the overarching demographic challenge of the twenty-first century – demographic ageing. Each chapter is introduced in the context of the specific theme to which it primarily relates and there is a summary of the data sets used by the contributors to illustrate the wide range of cross-sectional and longitudinal data analysed

Multiple Motherhoods: The Effect of the Internalization of Motherhood Ideals on Life Satisfaction

Purpose – This study examined whether life satisfaction varied among women who occupy different motherhood statuses, and if these variations were influenced by differences in women’s internalization of cultural motherhood norms. We distinguished among women as biological mothers, stepmothers, and “double mothers,” who were both biological and stepmothers. We also included two groups of women without children: voluntary childfree and involuntary childless women. Design/methodology/approach – Data were drawn from the National Study of Fertility Barriers and analyzed using OLS regression. Findings – Biological mothers reported greater life satisfaction than women in other motherhood statuses. Accounting for the internalization of motherhood norms, double mothers had significantly lower life satisfaction compared to biological mothers, but voluntary childfree women had significantly greater life satisfaction. More detailed analyses indicated that internalization of cultural norms only appears to influence the life satisfaction of women with biological children. Research limitations/implications – The results suggest that it may not simply be motherhood that affects women’s well-being, but rather that women’s internalization of motherhood ideals, particularly when it corresponds with their motherhood status, significantly impacts well-being. Limitations of this study include small cell sizes for some categories of women where additional distinctions may have been useful, such as lesbian or adoptive mothers. Future work should incorporate diverse family forms and expand on the newly named category “double mothers.” Originality/value – By providing a more nuanced approach to categorizing motherhood status, including identifying double mothers, stepmothers-only, and two groups of childless women, the study added detail that has been overlooked in previous work on well-being

Black Men and the Decision to Marry

The purpose of this descriptive study is to understand the decision to marry among a sample of 52 married Black men. Qualitative inquiry was used to explore this issue. The men noted five factors that encouraged marriage: wife\u27s characteristics, spirituality, desire to be together, readiness to marry, and encouragement from others. Five barriers to marriage were personal reservations, perceived loss of freedom, disapproval from others, prior relationship experiences, and finances. If they had to make the choice to marry again, 44% reported they would marry at the same time, 30% would opt to marry later, and 23% would select to marry earlier. Three percent of men would not choose to marry again. Implications are discussed

Male Breadwinning Revisited: How Specialisation, Gender Role Attitudes and Work Characteristics Affect Overwork and Underwork in Europe

We examine how male breadwinning and fatherhood relate to men’s overwork and underwork in western Europe. Male breadwinners should be less likely to experience overwork than other men, particularly when they have children, if specialising in paid work suits them. However, multinomial logistic regression analysis of the European Social Survey data from 2010 (n = 4662) challenges this position: male breadwinners, with and without children, want to work fewer than their actual hours, making visible one of the downsides of specialisation. Male breadwinners wanting to work fewer hours is specifically related to the job interfering with family life, as revealed by a comparison of the average marginal effects of variables across models. Work–life interference has an effect over and beyond the separate effects of work characteristics and family structure, showing the salience of the way work and life articulate

Childhood in Sociology and Society: The US Perspective

The field of childhood studies in the US is comprised of cross-disciplinary researchers who theorize and conduct research on both children and youth. US sociologists who study childhood largely draw on the childhood literature published in English. This article focuses on American sociological contributions, but notes relevant contributions from non-American scholars published in English that have shaped and fueled American research. This article also profiles the institutional support of childhood research in the US, specifically outlining the activities of the ‘Children and Youth’ Section of the American Sociological Association (ASA), and assesses the contributions of this area of study for sociology as well as the implications for an interdisciplinary field.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline