Solution to the problem of the poor cyclic fatigue resistance of bulk metallic glasses

The recent development of metallic glass-matrix composites represents a particular milestone in engineering materials for structural applications owing to their remarkable combination of strength and toughness. However, metallic glasses are highly susceptible to cyclic fatigue damage, and previous attempts to solve this problem have been largely disappointing. Here, we propose and demonstrate a microstructural design strategy to overcome this limitation by matching the microstructural length scales (of the second phase) to mechanical crack-length scales. Specifically, semisolid processing is used to optimize the volume fraction, morphology, and size of second-phase dendrites to confine any initial deformation (shear banding) to the glassy regions separating dendrite arms having length scales of ≈2 μm, i.e., to less than the critical crack size for failure. Confinement of the damage to such interdendritic regions results in enhancement of fatigue lifetimes and increases the fatigue limit by an order of magnitude, making these “designed” composites as resistant to fatigue damage as high-strength steels and aluminum alloys. These design strategies can be universally applied to any other metallic glass systems

Effect of Banded Fertilizer on Manganese Toxicity of Burley Tobacco

Relatively large amounts (1500 to 3000 lbs per acre) of inorganic fertilizers are commonly broadcast preplant in the production of burley tobacco. Such high rates of fertilizer increase both the salt content of the soil solution and soil acidity, often causing reduced stands, manganese toxicity, plant molybdenum and calcium deficiencies, delayed growth and maturity, and reduced yield and quality of cured leaf. Manganese toxicity alone is thought to cost growers 30-40 million dollars each year from yield loss and the costs associated with growing extra acreage the following year to make up their quota¥ Improved fertilizer management systems are needed to increase early plant growth and fertilizer use efficiency. The objective of this study was to determine the effect of banding fertilizer 10 to 12 inches to the side of the row, as compared to preplant broadcast applications, on concentration of manganese and growth of burley tobacco during the early season

\u3ci\u3eFamilies, Crime and Criminal Justice: Charting the Linkages\u3c/i\u3e

Contemporary Perspectives in Family Research is a series of volumes that features scholarly work on the frontiers of interdisciplinary research on families and family life. Volume 2, Families, Crime and Criminal Justice reflects this pioneering orientation by bringing together new empirical research that examines the various ways that families intersect with and are affected by crime and the criminal justice system. The interdisciplinary nature of the volume is reflected in the diversity of disciplines represented, including developmental psychopathology, criminology, sociology, family studies, psychology, social work and demography. The inclusion of qualitative studies based upon observational techniques and in-depth, long interviews as well as quantitative work using demographic and survey approaches demonstrates the wide methodological range employed by the authors. The topics examined include the involvement of children in crime, the patterns and impact of violence in the home, the impact of criminal involvement on parenting strategies and youth development, the experience of families of victims and perpetrators, and responses of the criminal justice system to the needs of families

\u3ci\u3eFamilies, Crime and Criminal Justice: Charting the Linkages\u3c/i\u3e

Chapter: Gender Differences in the Effect of Child Maltreatment on Criminal Activity over the Life Course, written by Ryan Spohn, UNO faculty member. Contemporary Perspectives in Family Research is a series of volumes that features scholarly work on the frontiers of interdisciplinary research on families and family life. Volume 2, Families, Crime and Criminal Justice reflects this pioneering orientation by bringing together new empirical research that examines the various ways that families intersect with and are affected by crime and the criminal justice system. The interdisciplinary nature of the volume is reflected in the diversity of disciplines represented, including developmental psychopathology, criminology, sociology, family studies, psychology, social work and demography. The inclusion of qualitative studies based upon observational techniques and in-depth, long interviews as well as quantitative work using demographic and survey approaches demonstrates the wide methodological range employed by the authors. The topics examined include the involvement of children in crime, the patterns and impact of violence in the home, the impact of criminal involvement on parenting strategies and youth development, the experience of families of victims and perpetrators, and responses of the criminal justice system to the needs of families.https://digitalcommons.unomaha.edu/facultybooks/1161/thumbnail.jp

Electron transport properties of sub-3-nm diameter copper nanowires

Density functional theory and density functional tight-binding are applied to model electron transport in copper nanowires of approximately 1 nm and 3 nm diameters with varying crystal orientation and surface termination. The copper nanowires studied are found to be metallic irrespective of diameter, crystal orientation and/or surface termination. Electron transmission is highly dependent on crystal orientation and surface termination. Nanowires oriented along the [110] crystallographic axis consistently exhibit the highest electron transmission while surface oxidized nanowires show significantly reduced electron transmission compared to unterminated nanowires. Transmission per unit area is calculated in each case, for a given crystal orientation we find that this value decreases with diameter for unterminated nanowires but is largely unaffected by diameter in surface oxidized nanowires for the size regime considered. Transmission pathway plots show that transmission is larger at the surface of unterminated nanowires than inside the nanowire and that transmission at the nanowire surface is significantly reduced by surface oxidation. Finally, we present a simple model which explains the transport per unit area dependence on diameter based on transmission pathways results

Associations Between Sociodemographic Characteristics and Perceptions of the Built Environment With the Frequency, Type, and Duration of Physical Activity Among Trail Users

Introduction Rail trails are elements of the built environment that support the Task Force on Community Preventive Services\u27 recommendation to create, or enhance access to, places for physical activity (PA). The purpose of this study was to examine the associations between sociodemographic characteristics and perceptions of the built environment with the frequency, type, and duration of PA among users of an urban, paved rail trail segment. Methods Interviewers conducted intercept surveys with 431 rail trail users and analyzed data by using logistic regression to estimate odds ratios between sociodemographic characteristics and perceptions of the built environment on the frequency, type, and duration of PA performed on the trail. Results Adults who used the trail in the cool months, traveled to the trail by a motorized vehicle, used the trail with others, and had some graduate school education visited the trail less often. Younger adults, men, whites, and those with some graduate school education were more likely to engage in vigorous activities on the trail. Adults who traveled to the trail by a motorized vehicle spent more time engaged in PA on the trail. Conclusion Our results suggest that the most frequent users of a rail trail for PA are those who use the trail alone and travel to the trail by bicycle or on foot. Trails are an aspect of the built environment that supports active lifestyles, and future studies should evaluate different types of trails among more diverse populations and locations

Skewed task conflicts in teams: what happens when a few members see more conflict than the rest?

Task conflict has been the subject of a long-standing debate in the literature—when does task conflict help or hurt team performance? We propose that this debate can be resolved by taking a more precise view of how task conflicts are perceived in teams. Specifically, we propose that in teams, when a few team members perceive a high level of task disagreement while a majority of others perceive low levels of task disagreement—that is, there is positively skewed task conflict, task conflict is most likely to live up to its purported benefits for team performance. In our first study of student teams engaged in a business decision game, we find support for the positive relationship between skewed task conflict and team performance. In our second field study of teams in a financial corporation, we find that the relationship between positively skewed task conflict and supervisor ratings of team performance is mediated by reflective communication within the team