SLS Materials Development Method for Rapid Manufacturing

As soon as SFF technology development began to make Rapid Prototyping possible the interest in Rapid Manufacturing (RM) began to grow. The advantages in terms of functional integration, elimination of tooling and fixtures and mass customization make a compelling case for RM, leading some in the field to call it the next industrial revolution. Yet without the materials properties necessary to provide the function and variety currently available from mass production methods, the application of RM will remain limited. Developing new materials for the SLS process, one immediate step toward a larger portfolio of RM materials, is very challenging. The formation of high quality SLS parts relies on appropriate powder characteristics, thermal cycles and sintering behavior. Based on a brief examination of the key factors in SLS processing and a research project to develop a new binder material for Silicon Carbide composites, a systematic materials development method is proposed in this paper. The method provides guidance for introducing new SLS materials, support for educating new SLS users and researchers and direction for several future research projects.Mechanical Engineerin

Rapid Manufacturing of Silicon Carbide Composites

From the earliest days of SFF technology development, a viable technique for the direct manufacture of fully-functional parts has been a major technology goal. While direct metal methods have been demonstrated for a variety of metals including aluminum, steel and titanium, they have not reached wide commercial application due to processing speed, final material properties and surface finish. In this paper the development of an SLS-based rapid manufacturing (RM) platform is reviewed. The core of this platform is a thermosetting binder system for preform parts in contrast to the thermoplastic materials currently available for SLS. The preforms may include metal and/or ceramic powders. A variety of fully functional parts can be prepared from different combinations of materials and post processing steps including binder pyrolysis, free-standing alloy infiltration, room temperature polymer infiltration and machining. The main issues of these steps are reviewed followed by a discussion about the support of RM. This paper is an intermediate report additional materials, applications, process models and product design strategies will be incorporated into the project in the next year.Mechanical Engineerin

Negative priming in free recall reconsidered

Recent investigations of the phenomenon of forgetting have been driven mostly by the development of a novel theoretical framework which places great emphasis on inhibitory control (Anderson, 2003; Anderson & Spellman, 1995; Bjork, 1989). Whereas traditional, interference-based theories consider forgetting to be a by-product of storing new information, the inhibitory framework postulates a specialized mechanism, or a group of mechanisms, that serves the function of ‘deactivating’ information which is currently irrelevant. This process of inhibiting currently irrelevant information is thought to have lasting consequences, affecting memory for the irrelevant information on subsequent tests. The active and functional perspective on forgetting embedded in the inhibitory framework opens new fields for examining the role of forgetting in cognitive functioning. Differences in the ability to inhibit irrelevant information have been postulated to play important roles in a range of clinical conditions (e.g., Soriano, Jiménez, Román, & Bajo, 2009; Storm & White, 2010) and the trajectory of cognitive development (e.g., Aslan & Bäuml, 2010) as well as contributing to individual differences in many other cognitive and social domains (Redick, Heitz, & Engle, 2007)

Learning through clamor: the allocation and perception of study time in noise

Memory tasks involve a degree of judgment and strategic decision-making, based upon the perceived benefits of particular learning, maintenance and recall strategies. The consequences of these metacognitive judgments for memory have been amply documented under experimental conditions that require participants to focus upon a task in the absence of distractors. Eight experiments consider the impact of less benign environmental conditions —specifically, the presence of distracting speech —upon the metacognitive aspects of memory. Distraction reliably disrupted free recall and, as indicated by Judgments of Learning, participants were aware of this effect. However, because participants did not adjust study time in compensation, the distraction effect was exaggerated relative to experimenter-imposed presentation rates. This finding appears to be the consequence of distraction-induced disruption of time perception at encoding, rather than any deliberate strategy. The results are interpreted in terms of a limited self-regulation hypothesis and highlight the need to consider the impact of more challenging environments on metacognition generally

Developing a Set of Indicators to Assess End-of-Life Care in Massachusetts Nursing Homes: Final Report

Nursing homes are often the final residence for many people. Studies have estimated that as many as 20 to 25 percent of deaths due to chronic illness in the U.S. occur in nursing homes. In recognition of the trend of increasing utilization of nursing homes as a setting for the end of life, and the opportunities and challenges for end-of-life care in nursing homes, in July 2004, Commonwealth Medicine (a division of the UMass Medical School) awarded an internal grant to the study team to develop a set of indicators that can be used to assess and evaluate the appropriateness of end-of-life care for residents of nursing homes in Massachusetts. The indicators and the results of the analysis are a basis from which future research can be conducted, and from which quality improvement programs can be initiated. This report presents the project’s results. The project was guided by an advisory group of researchers, nursing home administrators, directors of nursing, geriatricians, advocates, and policy makers. First, a comprehensive literature review was conducted to inform the project. Second, a set of indicators were developed within seven domains of end of life care: 1) structure and processes of care; 2) physical and emotional aspects of care; 3) advanced care planning; 4) ethical and legal aspects of care; 5) aggressive care near death; 6) family satisfaction; and 7) provider continuity, skill, and satisfaction. Third, the indicators were prioritized by the advisory group using a structured prioritization process in order to determine which indicators had the most relevance to assessing end-of-life care in the nursing home setting. Fourth, baseline data were collected for a small set of indicators. Data were collected from Massachusetts Medicaid claims data and a family survey. A total of 44 indicators were developed in the seven domains. The indicators within each domain were prioritized and the results of the structured prioritization process are provided in the body of the report. Baseline data were collected for five of the indicators: death in hospital; overall hospice use; length of stay on hospice; total Medicaid resource use at the end of life; and family satisfaction. This project sets forth a slate of indicators that can be used by nursing homes, coalitions, community groups, state agencies, and researchers to evaluate the quality of end-of-life care in nursing homes. With long histories of providing care to this vulnerable population, nursing homes can be well-positioned in the future to provide symptom management, advance care planning support, appropriate care to the imminently dying, and emotional support to staff and other residents. However, nursing homes face many challenges to providing high-quality end-of-life care. With continuing attention on the strengths of nursing homes and the needs of dying residents, improvements in the processes of care and the policy environment to support high-quality end-of-life care are possible. Moreover, the indicators presented in this report can provide the critical tools in evaluating the success of future interventions to improve the end-of-life care for nursing home residents

New constraints on the postglacial shallow-water carbonate accumulation in the Great Barrier Reef

More accurate global volumetric estimations of shallow-water reef deposits are needed to better inform climate and carbon cycle models. Using recently acquired datasets and International Ocean Discovery Program (IODP) Expedition 325 cores, we calculated shallow-water CaCO3 volumetrics and mass for the Great Barrier Reef region and extrapolated these results globally. In our estimates, we include deposits that have been neglected in global carbonate budgets: Holocene Halimeda bioherms located on the shelf, and postglacial pre-Holocene (now) drowned coral reefs located on the shelf edge. Our results show that in the Great Barrier Reef alone, these drowned reef deposits represent ca. 135 Gt CaCO3, comparatively representing 16-20% of the younger Holocene reef deposits. Globally, under plausible assumptions, we estimate the presence of ca. 8100 Gt CaCO3 of Holocene reef deposits, ca. 1500 Gt CaCO3 of drowned reef deposits and ca. 590 Gt CaCO3 of Halimeda shelf bioherms. Significantly, we found that in our scenarios the periods of pronounced reefal mass accumulation broadly encompass the occurrence of the Younger Dryas and periods of CO2 surge (14.9-14.4 ka, 13.0-11.5 ka) observed in Antarctic ice cores. Our estimations are consistent with reef accretion episodes inferred from previous global carbon cycle models and with the chronology from reef cores from the shelf edge of the Great Barrier Reef

Spatio-temporal patterns in the postglacial flooding of the Great Barrier Reef shelf, Australia

The shelf of the Great Barrier Reef (GBR) was progressively marine flooded from the last glaciation maximum (LGM) (ca 20 ka BP) until the last sea-level highstand (ca 6 ka BP), affecting the depositional evolution of the GBR margin and associated deposits. However, the physiographic variables related to this process have not been fully characterized, especially in relation to the sedimentary processes at the shelf margin. For this study, we used a bathymetric model of the entire shelf and a shelf margin sub-set, divided into 33 latitudinal zones. Postglacial marine flooding was simulated and flooded area (km2), flooding magnitude (km2 per sea-level increment), flooding rate (km2. ky−1) and coastline length (km) were estimated for each zone, from 130 m to 0 m below present sea level, representing the period from 20 ka to 6 ka BP. Our results show that the postglacial marine flooding did not occur uniformly and that some sub-regions (e.g. the southern-central GBR) had early and rapid flooding. Coastal complexity increased in the mid-postglacial, reaching maximum values at around 9 ka BP. This reflects a coastal landscape evolving from a linear, laterally connected coast to a complex coast dominated by estuaries and lagoons, partly returning to its initial linearity during highstand. Flooding trends and geological evidence make two depositional relationships apparent. Firstly, the timing and magnitude of the off-shelf sediment flux appears linked to the presence and orientation of a shelf-edge rim, and to the extension and morphology of the evolving drainage network. Secondly, the periods of shelf-edge reef development and demise seem to respond to the remobilisation, trapping or redirection of fine sediments. We propose a sedimentation model for the shelf margin and the slope driven by the interplay of sea-level rise and shelf physiography, and we highlight two fundamental processes: (1) the cross-shelf sediment transport related to coastline retreat under rising sea levels, and (2) the effectiveness of transient embayments in redirecting or trapping sediments. The quantifications provided in this study have implications in the estimation of Pleistocene carbonate budgets and the atmospheric carbon cycle, as well as for past human migrations

Simple prompts reduce inadvertent energy consumption from lighting in office buildings

Building designs regularly fail to achieve the anticipated levels of in-use energy consumption. The interaction of occupants with building controls is often cited as a key factor behind this discrepancy. This paper examines whether one factor in inadvertent energy consumption might be the appearance of post-completion errors (when an intended action is not taken because a primary goal has already been accomplished) in occupants’ interactions with building controls. Post-completion errors have been widely studied in human-computer interaction but the concept has not previously been applied to the interaction of occupants with building controls. Two experiments were carried out to examine the effect of incorporating two different types of simple prompt to reduce post-completion error in the use of light switches in office meeting rooms. Results showed that the prompts were effective and that occupants switched off lights when leaving the room more often when presented with a normative prompt than with a standard injunction. Additionally, an over reliance on PIR sensors to turn off lights after meetings was observed, which reduced their intended energy savings. We conclude that achieving low carbon buildings in practice is not solely a technological issue and that application of user-models from human-computer interaction will encourage appropriate occupant interaction with building controls and help reduce inadvertent energy consumption

Long Term Gait, Mobility, and Daily Living Outcomes after Orthopedic Surgery for Youth with Cerebral Palsy: Influence of Rehabilitation Dose and Setting

Background/Purpose: Cerebral palsy (CP) is a broad diagnostic description of early brain insult causing motor impairment. To help correct gait abnormalities, many children with CP undergo an orthopedic single event multi-level surgery (SEMLS). After surgery and most importantly SEMLS, rehabilitation is important to recovery. The purpose of this study was to examine the effects of post-op therapy setting and dose on functional mobility outcomes for youth with CP. Methods: Outcome measures included gait deviation index (GDI), walking speed, Pediatrics Outcomes Data Collection Instrument (PODCI), Gross Motor Function Mobility-D (GMFM-D). Data on post-op rehab therapy were retrieved from electronic medical records. Multiple Regression, Two-Way ANOVA, and Welch’s t-tests were used. Patient Sample: 74 cases were eligible. Average age at baseline gait analysis was 11.5, at surgery was 12, and at post-op gait analysis was 13.3 years old, with Gross Motor Function Classification System (GMFCS) levels I (9%), II (53%), III (34%), and IV (4%). Results: There was variability in therapy setting, with 33 different therapy centers. Higher burden of surgery was associated with more therapy sessions. Patients with low burden surgeries tended to improve in PODCI scores, but patients with high burden surgeries did not. These trends were not related to therapy dose, however, patients receiving Nemours Outpatient therapy had a positive association with PODCI gains. Similarly, patients who had low burden surgery improved GMFM-D and those with high burden did not. A minimal threshold of therapy dose was identified for cases with low burden surgery. Patients who attended 46 sessions or more saw GMFM-D improvements and patients who attended 25 sessions or fewer did not improve. Conclusion: Clinical practice recommends rehab therapy after SEMLS, but implementation is inconsistent. Post-op therapy varied widely by setting and number of sessions. As expected, youth who had low-burden surgery had less post-op therapy. Those above a minimum threshold and those at Nemours settings tended to show improvement at one-year post-op. At one year post-op, youth with high burden surgery demonstrated less gains, which is likely related to ongoing recovery in year two

NASA's Space Launch System Progress Report

Exploration beyond Earth will be an enduring legacy for future generations, confirming America's commitment to explore, learn, and progress. NASA's Space Launch System (SLS) Program, managed at the Marshall Space Flight Center, is responsible for designing and developing the first exploration-class rocket since the Apollo Program's Saturn V that sent Americans to the Moon. The SLS offers a flexible design that may be configured for the MultiPurpose Crew Vehicle and associated equipment, or may be outfitted with a payload fairing that will accommodate flagship science instruments and a variety of high-priority experiments. Both options support a national capability that will pay dividends for future generations. Building on legacy systems, facilities, and expertise, the SLS will have an initial lift capability of 70 metric tons (mT) and will be evolvable to 130 mT. While commercial launch vehicle providers service the International Space Station market, this capability will surpass all vehicles, past and present, providing the means to do entirely new missions, such as human exploration of asteroids and Mars. With its superior lift capability, the SLS can expand the interplanetary highway to many possible destinations, conducting revolutionary missions that will change the way we view ourselves, our planet and its place in the cosmos. To perform missions such as these, the SLS will be the largest launch vehicle ever built. It is being designed for safety and affordability - to sustain our journey into the space age. Current plans include launching the first flight, without crew, later this decade, with crewed flights beginning early next decade. Development work now in progress is based on heritage space systems and working knowledge, allowing for a relatively quick start and for maturing the SLS rocket as future technologies become available. Together, NASA and the U.S. aerospace industry are partnering to develop this one-of-a-kind asset. Many of NASA's space centers across the country will provide their unique expertise to the Space Launch System endeavor. Unique infrastructure to be used includes the Michoud Assembly Facility for tank manufacturing, Stennis Space Center for engine testing, and Kennedy Space Center for processing and launch. As this panel will discuss, the SLS team is dedicated to doing things differently-from applying lean oversight/insight models to smartly using legacy hardware and existing facilities. Building on the foundation laid by over 50 years of human and scientific space flight--and on the lessons learned from the Apollo, Space Shuttle, and Constellation Programs-the SLS team has delivered both technical trade studies and business case analyses to ensure that the SLS architecture will be safe, affordable, reliable, and sustainable