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    61545 research outputs found

    LPBF and Post Processing of H13 Tool Steel

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    Laser powder bed fusion (LPBF) is an innovative method where metal powder is fused together to generate complex geometries. LPBF is used as a technology to reduce material waste, and extensive labor that are often linked to conventional subtractive manufacturing. H13 tool steel is one of the widely used materials in several industries and has, therefore, gained interest in the additive manufacturing field due to its excellent mechanical properties. To produce H13 parts with optimal mechanical properties, printing parameters are optimized and a high relative density of 98% is obtained. Laser power of 203W, scanning speed of 700 mm/s, hatch spacing of 40μm and layer thickness of 25 μm are used to obtain the optimal results. Hot isostatic pressing is applied to cure the microcracks and has shown a 0.5% increase in the relative density, while it showed a significant decrease in other samples due to the excessive residual heat. Optical and scanning electron microscopy are used to observe the recrystallization of grains and grain growth resulted by tempering and rapid cooling. Tempering temperatures of 650˚C resulted in a greater reduction of microhardness than 550 ˚C. While high hot isostatic pressing temperature (1163 ˚C) shows a worsening effect on the microstructures

    Northern spotted owl reproductive rates

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    These datasets were used in the prospective meta-analysis of northern spotted owl reproductive rates over 25 years across 11 study areas located throughout the range of the owl. A multi-state occupancy file was created by collapsing site-specific information on owl reproductive status into bimonthly (2 per month) survey occasions. These data were then analyzed to estimate annual reproductive rates, defined as: number of owls successfully reproducing/number of owl pairs, while accounting for variation in survey effort by accounting for imperfect detection of owls and potential misclassification of reproductive status. Covariates describing the probability of barred owl presence, habitat conditions, and climate were also included to explain variation in reproductive rates. These data were collected as part of the long-term demographic monitoring of northern spotted owls in association with the Effectiveness Monitoring Plan of the Northwest Forest Plan. Data included here were analyzed and interpreted in the following manuscript in review: Rockweit, J. T. et al. 2021. Sources of Variation in Reproductive Rates of Northern Spotted Owls Across Their Range: A Prospective Meta-Analysis.The datasets associated with this readme file include all relevant script files needed for the multi-state occupancy analysis of northern spotted owl reproduction. For specific file information see the readme files in this record. These data were collected as part of the long-term demographic monitoring of northern spotted owls in association with the Effectiveness Monitoring Plan of the Northwest Forest Plan

    BeanCAP snap bean diversity panel SNP data

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    Genotype data consisting of 10,546 single nucleotide polymorphisms on the Illumina Infinium Genechip BARCBEAN6K_3 platform for 149 snap bean accessions.The accessions used to create the Snap Bean Diversity Panel were 149 snap bean accessions selected from North American and European germplasm. This panel was developed with support from the Common Bean Coordinated Agriculture Project (USDA-NIFA grant no. 2009-85606-05964). A modified CTAB procedure was used to extract genomic DNA and the resulting DNA samples were analyzed on an Illumina Infinium Genechip BARCBEAN6K_3 platform. The single nucleotide polymorphism (SNP) array utilized was composed of 10,546 allele-specific probes. The raw data was initially processed on GenomeStudio (v2.0.4) software (Illumina, San Diego, CA, USA). Two marker SNP positions contained greater than 20% missing data and were removed from the study. All missing data for the remaining SNPs was imputed using fastPHASE software (v1.4), including heterozygous SNPs which were treated as missing data. SNPs not assigned to a genomic position in Phytozome12 (Phaseolus vulgaris, version 2.1) were removed from the study resulting in 10,073 remaining SNPs

    Assessing the feasibility of a sea otter reintroduction to Oregon through a coupled natural-human lens

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    Sea otters fulfill a keystone role in several Northeastern Pacific nearshore ecosystems. However, their influence has been absent in Oregon coastal waters since their extirpation in the 19th and early 20th century. Interest has been growing for a translocation attempt to reintroduce sea otters to Oregon from one or more source populations of the southern sea otter and northern sea otter subspecies. Numerous unanswered questions require inquiry before a productive discussion can take place on the advisability of such an effort. A successful reintroduction would alter the existing coupled natural-human system dynamics between Oregon coastal communities, Oregon residents as a whole, and the nearshore environment. The appropriate source of reintroduction stock bears discussion, as do the optimal sites on the Oregon coast for a translocation effort and stakeholders’ attitudes towards such a proposal. This paper considers select issues related to the genetics, ecology, and human dimensions of a potential Oregon sea otter reintroduction, integrating insights from each discipline to provide a preliminary interdisciplinary examination

    Deer-mediated ecosystem service vs. disservice depends on forest management intensity - Dataset

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    This dataset consists of planted crop-tree growth metrics (Pseudotsuga menziesii), non-crop tree vegetation metrics, and foraging data for black-tailed deer (Odocoileus hemionus columbianus) and Roosevelt elk (Cervus canadensis rooseveli) collected from the Intensive Forest Management experiment, Oregon Coast Range, USA, 2011-2016. The objective of the experiment was to quantify the effects of silvicultural herbicide treatments on biodiversity and ecosystem functions.MANUSCRIPT ABSTRACT As global terrestrial biodiversity declines via land-use intensification, society has placed increasing value on non-commercialspecies as providers of ecosystem services. Yet, many deer species and non-crop plants are perceived negatively when they decrease crop productivity, leading to reduced economic gains and human-wildlife conflict. We hypothesized that deer provide an ecosystem service in forest plantations by controlling competition and promoting crop-tree growth, although the effects of herbivory may depend on forest management intensity. If management negatively affects foraging habitat at local and landscape scales, then we expected browsing to shift to less-palatable crop trees. To test these hypotheses, we established a 5-year experiment that manipulated early forest management intensity via herbicide treatments and access of two deer species to vegetation via exclosures. Contrary to our hypothesis, deer provided an ecosystem service at high management intensities and a disservice occurred with low-intensity management. Crop-tree growth and survival was greatest when herbivory and herbicides suppressed broadleaf regeneration. In contrast, crop-tree growth was lowest when broadleaf vegetation was retained and crop-trees were subject to both browse damage and competition. We found a positive, yet variable, association between deer detections and stand- and landscape-scale broadleaf habitat, and despite initial reductions in forage, herbivory pressure was similar among management intensities. When broadleaf vegetation was suppressed by herbicides and herbivory, selection of herbaceous forage by deer intensified, likely aiding in the service. Overall, our findings indicate that the effects of vegetation management for promoting timber production are highly dependent on the presence of large herbivores. Synthesis and applications: Although deer are thought to reduce crop productivity in many systems, we found that herbivory switched from reducing crop tree growth where non-crop vegetation was retained, to promoting crop tree growth when both herbivory and herbicides suppressed competing vegetation. However, the provision of this ecosystem service is likely contingent on the amount of forage available in the landscape and subsequent foraging pressure. We conclude that nature’s capacity to provide ecosystem services depends on the intensity of management at local and landscape scales.Keywords: Elk (Cervus canadensis roosevelti); Deer (Odocoileus hemionus columbianus); Douglas-fir (Pseudotsuga menziesii

    Bean CAP Snap Bean Diversity Panel Passport Data

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    The accessions used to create the Snap Bean Diversity Panel were 150 snap bean (Phaseolus vulgaris) cultivars and breeding lines selected from North American and European germplasm to create a population that is representative of the snap bean market class from a historical and geographical viewpoint. This panel was developed with support from the Common Bean Coordinated Agriculture Project (USDA-NIFA grant no. 2009-85606-05964). The passport data provides information on when and where these cultivars were developed. This panel has been genotyped using the Illumina Infinium Genechip BARCBEAN6K_3 platform. This SNP data has also been deposited in OSU ScholarsArchive and can be accessed using the link https://ir.library.oregonstate.edu/concern/datasets/m900p1589

    Low-Income Adolescents’ Physical Activity Levels in Rural Coastal Community: A Gender and Ethnic Comparison.

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    Physical Activity (PA) has been shown to significantly improve the overall health of adolescents. The health dimensions that are positively influenced by a consistent level of PA are multiple and range from body composition, chronic diseases management (diabetes, cardiovascular disease, etc.), chronic pain, and mental health (depression, anxiety, etc.). The US Department of Health and Human Services and the World Health Organization’s guidelines for PA and recommendations for optimal health established a minimum of 60 minutes of moderate to vigorous PA daily for adolescents. This study focused on physical activity data collected in a remote coastal rural county in the Pacific Northwest. The population was composed of 22 low income boys and girls, 12-14 years old in middle school, Hispanic and Non-Hispanic Whites. The 14 days of physical activity data consisted of pedometer steps counts and minutes, 3-Day Physical Activity Recall instrument, and Body Mass Index. The participants accumulated 10 days of step counts during weekdays and four (4) days of steps counts during weekend. Statistical analysis was performed using Wilcoxon Rank sum, and t-test. The participants did not meet daily physical activity recommendations. The results of the non-parametric test Wilcoxon Rank (Mann-Whitney) test were consistent with the results from the t-test, when compared by gender Females z scores were significantly different than the Males during the weekends, z= 2.04, P> |z| = 0.48 (p< 0.05). There were no significant differences among ethnic groups nor BMI categories. These results highlight the importance of policy efforts to create opportunities for adolescents in rural community, as well as the need for tailored interventions to meet the needs in isolated rural counties in the pacific northwest to enhance the overall health outcomes of future adults

    Bottom Characterization from Hyperspectral Image Data

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    In optically shallow waters, i.e., when the bottom is visible through the water, a tantalizing variety and level of detail about bottom characteristics are apparent in aerial imagery (Figure 1a). Some information is relatively easy to extract from true color, 3-band imagery (e.g., the presence and extent of submerged vegetation), but if more precise information is desired (e.g. the species of vegetation), spatial and spectral detail become crucial. That such information is present in hyperspectral1 imagery is clear from Figure 1b, which illustrates the Remote Sensing Refl ectance spectra for several selected points in the image. Spectral discrimination among bottom types will be greatest in shallow, clear water and will decrease as the depth increases and as the optical water quality degrades. Discrimination can also be complicated by the presence of vertical structure in the optical properties of the water, or even if there is a layer of suspended material near the bottom (see Box on opposite page). Despite these diffi culties, bottom characterization over the range of depths accessible to remote sensing is important since it corresponds to a signifi cant portion of the photic zone in coastal waters. Mapping bottom types at these depths is useful for applications related to habitat, shipping and recreation. The purpose of this paper is to present the issues affecting bottom characterization and to describe various methods now in use. Given space limitations, we refer the reader to the references for results and examples of bottom type maps

    Seasonal spillover and varve formation in the Santa Barbara Basin, California

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    A temporal record of oxygen and NO3- concentrations in the bottom water of the Santa Barbara Basin indicates that outside waters spill over into the basin seasonally. It is proposed that an annual bottom-water cycle leads ultimately to varve production. As evidence in support of a benthic mechanism for varve formation, we present results of surface sediment and pore-water analyses, from box-core collections during three seasons in 1988. The greater degree of bottom-water oxygen depletion that occurs regularly in late summer and fall was coincident with a smaller pool of pore-water Fe, penetration of ΣH2S up to the sediment-water interface, maximal numbers of benthic Foraminifera, and bacterial mat growth. The latter was indicated by increases in concentrations of extractable ATP, organic C, and total N in sediments from the depth intervals 0–0.25 and 0.25–0.5 cm. The greatest numbers of siliceous phytoplankton skeletons were found on the sea floor soon after the late spring, surface-water, Chl a maximum. This event coincides with additions of new and more-oxygenated seawater to the deep basin

    Uptake of ammonium and urea in the northeast Pacific: comparison between netplankton and nanoplankton

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    The stable isotope 15N was used to measure nitrogen uptake in the coastal upwelling region off Oregon and Washington, USA, where nitrate concentrations in the surface water ranged from 0.7 to 49.1 μM. Nanoplankton biomass (1 to 10 pm) was relatively more abundant at low-nitrate stations, while netplankton biomass (10 to 200 μm) was dominant at high-nitrate stations. Ammonium was more important than urea as a regenerated nitrogen source for both size classes of plankton, and ambient ammonium concentrations appeared to inhibit urea assimilation. Nanoplankton and netplankton were equally important in use of regenerated nitrogen in low-nitrate waters, while netplankton dominated nitrogen use in high-nitrate waters. In high-nitrate waters, the percent uptake in each size fraction was proportional to the percent particulate nitrogen (PN) and chlorophyll a (chl a) in that fraction. At low-nitrate stations, uptake in each fraction was proportional to PN but not to chl a. Nitrogen-specific (mass N taken up/mass particulate N) uptake rates ranged from 0.2 to 2.6 d-l, and were generally higher for the netplankton than for the nanoplankton fraction. However, these rates are not directly proportional to phytoplankton use as a result of varying amounts of non-phytoplankton N. Phytoplankton N was estimated by assuming a constant chl a/PN ratio for each size class, and used to calculate phytoplankton-specific uptake rates. Phytoplankton growth rates were estimated by extrapolating the short-term uptake rates to daily rates. Since calculated growth rates exceeded the expected maxima for phytoplankton In the low-nitrate coastal water, we postulate heterotrophic utilization of nitrogen

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