Thermal Behavior in the Lens Process

Direct laser metal deposition processing is a promising manufacturing technology which could significantly impact the length oftime between initial concept and finished part. For adoption ofthis technology in the manufacturing environment, further understanding is required to ensure robust components with appropriate properties are routinelyfabricated. This requires a complete understanding ofthe thermal history.during part fabrication and control ofthis behavior. This paper will describe our research to understand the thermal behavior for the Laser Engineered Net Shaping (LENS) process!, where a component is fabricated by focusing a laser beam onto a substrate to create a molten pool in which powder particles are simultaneously injected to build each layer. The substrate is moved beneath the l~ser beam to deposit a thin cross section, thereby creating the desired geometry for each layer. After deposition of each layer, the powder delivery nozzle and focusing lens assembly is incremented in the positive Z-direction, thereby building a three dimensional component layer additively. It is important to control the thermal behavior to reproducibly fabricate parts. The ultimate intent is to monitor the thermal signatures and to incorporate sensors and feedback algorithms to control part fabrication. With appropriate control, the geometric properties (accuracy, surface finish, low warpage) as well as the materials' properties (e.g. strength, ductility) of a component can be dialed into the part through the fabrication parameters. Thermal monitoring techniques will be described, and their particular benefits highlighted. Preliminary details in correlating thermal behavior with processing results will be discussed.Mechanical Engineerin

Navigating by the Stars: Library Leadership Lessons

In this unique and interactive Lively Lunch, participants will engage with four librarians with backgrounds in technical services and collections who transitioned to leadership roles. While some were thrust unexpectedly into the role, others followed a directed career trajectory. Yet, they all share the commonality of facing unforeseen challenges while seeking to emerge from the depths of inexperience. They will briefly share their experiences in leadership, as well as strategies for preparation, challenges they continue to face, and lessons they are still learning. Participants will learn about developing a personal leadership practice, as well as networking, mentoring, and professional development to prepare for senior leadership positions. They will also gain practical advice on managing the interview process and surviving the early days of the job. The panel will provide participants with a leadership “toolkit” that includes suggested readings, professional organizations, and educational opportunities, adding recommendations from participants throughout the Lively Lunch session

The Development of a Human Well-Being Index for the United States

The US Environmental Protection Agency (EPA) has developed a human well-being index (HWBI) that assesses the over-all well-being of its population at the county level. The HWBI contains eight domains representing social, economic and environmental well-being. These domains include 25 indicators comprised of 80 metrics and 22 social, economic and environmental services. The application of the HWBI has been made for the nation as a whole at the county level and two alternative applications have been made to represent key populations within the overall US population—Native Americans and children. A number of advances have been made to estimate the values of metrics for counties where no data is available and one such estimator—MERLIN—is discussed. Finally, efforts to make the index into an interactive web site are described

A Comparison Of Crassostrea Virginica And C. Ariakensis In Chesapeake Bay: Does Oyster Species Affect Habitat Function?

We examined the possibility that a nonnative oyster species would provide an ecologically functional equivalent of the native oyster species if introduced into the Chesapeake Bay. Habitat complexity and associated benthic communities of experimental triploid Crassostrea virginica and Crassostrea ariakensis reefs were investigated at 4 sites of varying salinity, tidal regime, water depth, predation intensity, and disease pressure in the Chesapeake Bay region (Maryland and Virginia). Four experimental treatments were established at each site: C. virginica, C. ariakensis, 50:50 of C. virginica and C. ariakensis, and shell only. Abundance, biomass, species richness, evenness, dominance, and diversity of reef-associated fauna were evaluated in relation to habitat location and oyster species. Although habitat complexity varied with location, no differences among complexity were associated with oyster species. Similarly, differences in faunal assemblages were more pronounced between sites than within sites. Our results show functional equivalency between oyster species with respect to habitat at the intertidal site and the low-salinity subtidal location. At subtidal sites of higher salinity, however, the numbers of organisms associated with C. virginica reefs per unit of oyster biomass were significantly greater than the numbers of organisms associated with C. ariakensis reefs. Multivariate analyses of data from subtidal high-salinity sites revealed unique communities associated with C. virginica treatments, whereas mixed-oyster species assemblages were functionally equivalent to monospecific C. ariakensis experimental treatments. Our study represents the first effort to quantify the potential habitat function of C. ariakensis, which has been proposed for an intentional introduction into Chesapeake Bay, and provides evidence of species-specific similarities and differences in reef-associated communities

Survival And Growth Of Triploid Crassostrea Virginica (Gmelin, 1791) And C-Ariakensis (Fujita, 1913) In Bottom Environments Of Chesapeake Bay: Implications For An Introduction

Survival and growth of triploid Crassostrea virginica and triploid C. ariakensis were investigated at four sites Surrounding Chesapeake Bay, United States, that varied tried in salinity, tidal regime, water depth, predation intensity and disease pressure. Four experimental treatments were established at each site: C. virginica; C. ariakensis; 50:50 of C. virginica: C. ariakensis: and shell only. Oysters were deployed at mean shell heights of 12.80 min and 13.85 mm (C. virginica and C. ariakensis, respectively), at an overall density of 347.5 oysters m(-2). Oyster survival and growth varied significantly, with site and species. Survival was significantly higher in C. virginica than C. ariakensis at the intertidal site, and significantly higher in C. ariakensis than C. virginica at the highest salinity, subtidal site. Survival did not differ significantly between species at the mid and low salinity, subticial sites. For both Species. survival differed significantly between sites, with lowest survival in both species Occurring Lit the intertidal site. Among the subtidal sites. C. virginica survival varied inversely with salinity, whereas C. ariakensis had the lowest Survival at the mid salinity site. Eight months after deployment C. ariakensis were significantly, larger than C. virginica at all sites. This difference generally persisted throughout the experiment, though the size differences between oyster species at the lowest salinity site were small (\u3c 10%). Shell heights within single-species treatments differed significantly between sites; highest growth rates were observed at the high salinity, subtidal site, whereas lowest growth rates were observed at the high salinity, intertidal site. At low and mid salinity subtidal sites, C. ariakensis shell heights were significantly greater in the single-species treatment compared with the mixed-species treatment. Perkinsus marinus infections occurred in both species at all sites, with prevalences varying between sites. In C. virginica, moderate and high intensity infections were only common at the two higher salinity sites, whereas infections in C. ariakensis were generally low, to rare. Haplosporidium nelsoni infections in C. virginica were only observed at the two higher salinity sites and prevalences were generally low. Two out of 53 C. ariakensis tested at the high salinity, subtidal site had rare H. nelsoni infections. Bonamia spp. infections were never observed. Our study supports previous laboratory findings and observations from its native range that C. ariakensis Survives poorly in intertidal habitats. In subtidal habitats, however, C. ariakensis displayed broad environmental tolerances, often exceeding native oyster Survival and growth rates. Post-introduction C. ariakensis Populations would be shaped by the survival and growth patterns described here, but also by their reproductive success, larval Survival, predator-prey interactions and prevailing disease dynamics

Experiencing parenthood, care and spaces of hospitality

Drawing on research conducted in Australia and the United Kingdom, this paper explores how parenting and care provision is entangled with, and thus produced through, consumption in hospitality venues. We examine how the socio-material practices of hospitality provision shape the enactment of parenting, alongside the way child-parent/consumer-provider interactions impact upon experiences of hospitality spaces. We argue that venues provide contexts for care provision, acting as spaces of sociality, informing children’s socialization and offering temporary relief from the work of parenting. However, the data also highlight various practices of exclusion and multiple forms of emotional and physical labour required from careproviders. The data illustrate children’s ability to exercise power and the ways in which parents’/carers’ experiences of hospitality spaces are shaped by their enactment of discourses of ‘good parenting’. Finally, we consider parents’/carers’ coping behaviours as they manage social and psychological risks associated with consumption in such public spaces of leisure

Regionalizing Resilience to Acute Meteorological Events: Comparison of Regions in the U.S.

Using a Climate Resilience Screening Index (CRSI) that was developed to represent resilience to acute weather events at multiple scales for the United States, nine regions of the United States are compared for resilience for these types of natural hazards. The comparison examines the domains, indicators, and metrics of CRSI addressing environmental, economic, and societal aspects of resilience to acute climate events at county scales. The index was applied at the county scale and aggregated to represent select regions of the United States. Comparisons showed higher levels of resilience in the Northeast and West, including Alaska, (>4.0) while counties in the South Atlantic and South-Central regions exhibited lower resilience (<2.0) to acute climate events. Northeast, West and Mountain regions of the US are characterized by relatively low levels of risk (<0.26), higher levels of governance (>0.60), and above national median scores for society, built environment and natural environment domains which enhances their resilience scores. South Atlantic and South-Central regions of the US are characterized by higher risk scores (>0.31) accompanied by lower levels of governance (<0.48) and below national median scores for society and built environment domains reducing the region's overall resilience

Role of lattice distortion and A site cation in the phase transitions of methylammonium lead halide perovskites

The rapid increase in power conversion efficiencies of photovoltaic devices incorporating lead halide perovskites has resulted in intense interest in the cause of their excellent properties. In the present paper, resonant ultrasound spectroscopy has been used to determine the elastic and anelastic properties of CH3NH3PbX3(where X=Cl, Br, or I) and CD3ND3PbI3 perovskites in the 5–380 K temperature range. This is coupled with differential scanning calorimetry, variable temperature neutron powder diffraction, and variable temperature photoluminescence studies to provide insights into the underlying processes and structural instabilities in the crystal structure. By comparing measurements on CH3NH3PbI3 with the deuterated equivalent, it has been possible to distinguish processes which are related to the hydrogen bonding between the methylammonium cation and the perovskite framework. We observe that replacing hydrogen with deuterium has a significant impact on both the elastic and photophysical properties, which shows that hydrogen bonding plays a crucial role in the material performance. Temperature-dependent photoluminescence studies show that the light emission is unaffected by the tetragonal-orthorhombic phase transition, but a blueshift in the emission and a steep increase in photoluminescence quantum yield are seen at temperatures below 150 K. Finally, observations of peaks in acoustic loss occurring in CH3NH3PbCl3 have revealed freezing processes in the vicinity of ∼150−170K, with activation energies in the range of 300 to 650 meV. These processes are attributed to freezing of the motion of methylammonium cations, and could explain the changes in photoluminescence seen in CH3NH3PbI3 at the same temperature. © 2018 American Physical Society. This work has been made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at: https://doi.org/10.1103/PhysRevMaterials.2.06540

Community Reaction to Bioterrorism: Prospective Study of Simulated Outbreak

To assess community needs for public information during a bioterrorism-related crisis, we simulated an intentional Rift Valley fever outbreak in a community in the southern part of the United States. We videotaped a series of simulated print and television “news reports” over a fictional 9-day crisis period and invited various groups (e.g., first-responders and their spouses or partners, journalists) within the selected community to view the videotape and respond to questions about their reactions. All responses were given anonymously. First-responders and their spouses or partners varied in their reactions about how the crisis affected family harmony and job performance. Local journalists exhibited considerable personal fear and confusion. All groups demanded, and put more trust in, information from local sources. These findings may have implications for risk communication during bioterrorism-related outbreaks