Hole cutter

An adjustable hole cutter is described for use in forming circular openings in workpieces. The hole cutter is characterized by a mount of a substantially planar configuration, positionable into a plane paralleling the working plane of a selected workpiece. It also contains a shaft for imparting rotary motion to the mount about an axis of rotation normally related to the working plane, a plurality of stabilizing struts for resiliently supporting the mount in parallelism with the working plane as rotary motion is imparted thereto, a drill bit for drilling a pilot hole concentric with the axis of rotation, and an elongated cutting tool adjustably seated within a radially extended slot

Design and evaluation of fluidized bed heat recovery for diesel engine systems

The potential of utilizing fluidized bed heat exchangers in place of conventional counter-flow heat exchangers for heat recovery from adiabatic diesel engine exhaust gas streams was studied. Fluidized bed heat recovery systems were evaluated in three different heavy duty transport applications: (1) heavy duty diesel truck; (2) diesel locomotives; and (3) diesel marine pushboat. The three applications are characterized by differences in overall power output and annual utilization. For each application, the exhaust gas source is a turbocharged-adiabatic diesel core. Representative subposed exhaust gas heat utilization power cycles were selected for conceptual design efforts including design layouts and performance estimates for the fluidized bed heat recovery heat exchangers. The selected power cycles were: organic rankine with RC-1 working fluid, turbocompound power turbine with steam injection, and stirling engine. Fuel economy improvement predictions are used in conjunction with capital cost estimates and fuel price data to determine payback times for the various cases

In situ anticaries efficacy of dentifrices with different formulations – A pooled analysis of results from three randomized clinical trials

Objectives Data generated from three similar in situ caries crossover studies presented the opportunity to conduct a pooled analysis to investigate how dentifrice formulations with different fluoride salts and combinations at concentrations of 1400–1450 ppm F, different abrasive systems and in some cases, carbomer (Carb), affect enamel caries lesion remineralization and fluoridation. Methods Subjects continuously wore modified partial dentures holding two gauze-covered partially-demineralized human enamel specimens for 14 days and brushed 2×/day with their assigned dentifrice: Study 1: sodium fluoride (NaF)/Carb/silica, NaF/silica, NaF + monofluorophosphate (MFP)/chalk; Study 2: NaF/Carb/silica, NaF + MFP/dical, amine fluoride (AmF)/silica; Study 3: NaF/Carb/silica, NaF + stannous fluoride (SnF2)/silica/hexametaphosphate (HMP). All studies included Placebo (0 ppm F) and/or dose-response controls (675 ppm F as NaF [675F-NaF]) ±Carb. Specimens were evaluated for percentage surface microhardness recovery (SMHR) and enamel fluoride uptake (EFU). Results All 1400–1450 ppm F dentifrices except NaF + SnF2/silica/HMP provided significantly greater lesion remineralization than Placebo (p < 0.0001): differences in SMHR ranged from 17.46% (NaF + MFP/dical) to 26.66% (AmF/silica). For EFU (back-transformed log EFU), all 1400–1450 ppm F dentifrices gave significant fluoride uptake compared to Placebo (p < 0.0001): increases in EFU ranged from 4.95 μg F/cm2 (NaF + SnF2/silica/HMP) to 16.32 μg F/cm2 (NaF/carb/silica). Dentifrices containing NaF or AmF as sole fluoride source provided the greatest remineralization and fluoridation; Carb addition did not alter fluoride efficacy; some excipients appeared to interfere with the cariostatic action of fluoride. Treatments were generally well-tolerated with ≤4 treatment-related adverse events per study. Conclusion Commercially available fluoride dentifrices varied greatly in their ability to remineralize and fluoridate early caries lesions. Clinical significance Fluoride dentifrices are the most impactful anticaries modality worldwide. While clinical caries trials have not consistently shown the superiority of one formulation over another, these findings using a sensitive in situ caries model indicated that dentifrices containing NaF or AmF as the sole fluoride source provided the greatest remineralization and fluoridation benefits

Catch Records of the Twenty North Pacific Right Whales from Two Alaska Whaling Stations, 1917-39

The North Pacific right whale population was hunted commercially between 1835 and 1935, at which time the species received protection. Commercial whalers harvested over 15,000 North Pacific right whales during this period, so reducing the population that today there are an estimated 100-200 right whales in the North Pacific. The American Pacific Whaling Company operated in the Gulf of Alaska and eastern Bering Sea during 1917-39. We report the distribution, sexes, and lengths of 20 right whales recorded in the company logbooks and ledgers. These records identify that right whale catches were widely distributed on the whaling grounds and tended to decrease over the May-October whaling season. Of the 17 whales for which sex and length data were documented, 11 were females. Their average length exceeded that of males. Lengths of the whales indicated that 41 percent of the catch were sexually mature; two females carried fetuses. Although the sample size is small, these results suggest that the North Pacific right whale population was inhabiting its historic summering grounds after the period of heavy exploitation in the 1800s, reproducing as late as 1926, and supporting a subadult cohort at least until the species was protected.Key words: right whale, North Pacific Ocean, Alaska, DistributionMots cl&eacute;s: baleine noire, nord de l'oc&eacute;an Pacifique, Alaska, distributio

River flow response to changes in vegetation cover in a South African fynbos catchment

Mountain fynbos catchments in the Western Cape region of South Africa are prone to substantial changes in land cover due to invasion by exotic tree species (and their clearing), fires, and vegetation response to inter-annual variations in rainfall. While small catchment experiments and modelling studies have pointed to reductions in river flow as catchment biomass increases, there is little empirical evidence of land cover change affecting river flow in large catchments that are important sources ofwater for the region. Monitoring changes in above-ground green biomass in multiple large catchments is challenging, but may be accomplished using a remotely sensed spectral vegetation index. It was hypothesised in this study that annual river yield (river flow as a fraction of rainfall) in the Molenaars catchment near Paarl, South Africa co-varies with an index of green vegetation cover derived from satellite data (the normalised difference vegetation index, NDVI). The catchment was partitionedinto &#8217;upland&#8216; and &#8217;lowland&#8216; zones and the relationship between annual river yield and summer NDVI was determined for each zone over an 18-year period. There was a statistically significant negative linear relationship between annual river yield and the NDVI of the lowland zone when three outliers were excluded from the analysis. These outliers correspondedto periods with prolonged drought conditions when river yield appeared to be decoupled from vegetation water use in the lowland zone. There was no relationship between river yield and changes in the NDVI in the upland zone where plants were unlikely to have sustained access to adequate soil water for transpiration. The importance of considering the location of landcover changes in a catchment, and inadequacies in high-elevation measurements of rainfall in this mountainous region, were highlighted in the study

Evaluating Terra MODIS Satellite Sensor Data Products for Maize Yield Estimation in South Africa

The Free State Province of the Republic of South Africa contains some of the most important maize-producing areas in South Africa. For this reason this province has also been selected as a Joint Experiment for Crop Assessment and Monitoring (JECAM, 2012) site representative of South Africa.The Terra (EOS AM-1) research satellite carries the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Two data products which are used in this research, created by the National Aeronautics and Space Administration (NASA) from the MODIS sensor, are the Normalised Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI).Objective yield points (OYP) are Global Positioning Points (GPS) that fieldworkers visit to record certain yield related data, including a final objective yield. Three research studies utilizing Terra MODIS data were performed. Study one utilised objective yields from the 2001/2002, 2004/2005 and 2005/2006 growth seasons for three provinces in South Africa. In study two, the 2006/2007 growth season OYP were extracted for the Free State province only. NDVI was downloaded from United States Geological Survey (USGS) for study one and two and extracted into a GIS for comparison with the OYP. For the Free State pilot study, study three, OYP from the 2001 to 2010 growth seasons were used. MODIS NDVI and EVI data were obtained from the Wide Area Monitoring Information System WAMIS portal for the data set of 35 points.Statistical analysis was done on the data of studies two and three. The 2006/2007 dataset yielded a R2 of 0.47 for all 225 points and 0.51 for the medium growth cultivar data only (186 data points), while the 2001 to 2010 growth season yielded an R2 of 0.63 for the medium yield group. Therefore it is concluded that Terra MODIS NDVI and EVI data can be utilized for maize yield estimation on points

Final NASA Panel Recommendations for Definition of Acceptable Risk of Injury Due to Spaceflight Dynamic Events

A panel of experts was convened in 2010 to help define acceptable injury risk levels for space vehicle launches, landings, and abort scenarios. Classifications of spaceflight-relevant injuries were defined using four categories ranging from minor to severe injury. Limits for each injury category were agreed to, dependent on the expected number of crew exposures in a given vehicle and on whether the flight was considered nominal or off-nominal. Somers et al. captured the findings of this summit in a NASA technical memorandum. This panel was recently re-convened (December 1, 2014) to determine whether the previous recommended injury limits were applicable to newly-designed commercial space flight vehicles. In particular, previous limits were based in part on the number of crew exposures per vehicle and also were sensitive to a definition of nominal and off-nominal vehicle performance. Reconsideration of these aspects led to a new consensus on a definition of injury risk

Assessing the Risk of Disc Heniation Related to Landing Impact Following Long-duration Spacecraft

Previous research has shown that crewmembers returning on the Space Shuttle have an increased incidence of herniated nucleus pulposus after spaceflight. This increased risk is thought to be related to disc volume expansion due to unloading and prolonged exposure to microgravity. Although there is an increased risk of disc herniation in Space Shuttle astronauts, it is unknown if dynamic landing loads further contribute to the risk of herniation. To determine if dynamic loads increase the risk of incidence, data from crewmembers (excluding cosmonauts) returning on the Soyuz spacecraft will be compared to Space Shuttle astronauts. These data will be obtained from the Lifetime Surveillance of Astronaut Health (LSAH) Project at NASA. Severity and incidence after spaceflight will be mined from the data, and statistical analyses will be used to determine if Soyuz crewmembers have a higher incidence of disc herniation than Space Shuttle crewmembers. The results are expected to show no difference between Space Shuttle and Soyuz crewmembers, indicating that higher dynamic loads on landing and long-duration spaceflight do not significantly increase the risk of disc herniation. If no difference is shown between the two crewmember populations, then disc volume expansion due to microgravity does not significantly increase the risk of injury due to dynamic loads for deconditioned crewmembers. Any risk associated with deconditioning would be primarily due to bone structure changes and resulting bone strength changes. This study is an important first step in determining whether the spinal disc plays a role in injury due to dynamic loads