SASRAD: An hourly-timestep solar radiation database for South Africa

A methodology is presented for the correction and filling of solar radiation data at sites within South Africa, with the aim of creating a continuous, hourly-timestep dataset for multiple locations. Data from twenty sites, collected by the Agricultural Research Council, are analysed with regard to the amount of data requiring offset or multiplier adjustment, as well as the amount of bad data. A range correction algorithm is implemented based on the 90th percentile (10% exceedance) hourly irradiance, as a function of site latitude and elevation. The resulting, corrected data set is given the title: South African Solar Radiation Database (SASRAD). Comparisons are made with two other solar radiation datasets, the South African Atlas of Agrohydrology and Climatology, and a limited set of older historical data from the South African Weather Service (SAWS). Results indicate that the SASRAD dataset matches well with other datasets, with major discrepancies apparently due to problems with the other data sets, rather than the SASRAD data. The Coefficient of Multiple Determination (R2) between the Atlas and SASRAD for monthly radiation is 0.927, and the mean error between three of the SASRAD sites and the corresponding SAWS data is 1.1 MJ m-2 d-1. The fraction of data requiring correction varied from 11% to 100%, depending on the site. The range correction algorithm was successful at correcting data that had been subject to incorrect calibration, and did not remove annual trends in mean radiation levels

SASRAD: An hourly-timestep solar radiation database for South Africa

A methodology is presented for the correction and filling of solar radiation data at sites within South Africa, with the aim of creating a continuous, hourly-timestep dataset for multiple locations. Data from twenty sites, collected by the Agricultural Research Council, are analysed with regard to the amount of data requiring offset or multiplier adjustment, as well as the amount of bad data. A range correction algorithm is implemented based on the 90th percentile (10% exceedance) hourly irradiance, as a function of site latitude and elevation. The resulting, corrected data set is given the title: South African Solar Radiation Database (SASRAD). Comparisons are made with two other solar radiation datasets, the South African Atlas of Agrohydrology and Climatology, and a limited set of older historical data from the South African Weather Service (SAWS). Results indicate that the SASRAD dataset matches well with other datasets, with major discrepancies apparently due to problems with the other data sets, rather than the SASRAD data. The Coefficient of Multiple Determination (R2) between the Atlas and SASRAD for monthly radiation is 0.927, and the mean error between three of the SASRAD sites and the corresponding SAWS data is 1.1 MJ m-2 d-1. The fraction of data requiring correction varied from 11% to 100%, depending on the site. The range correction algorithm was successful at correcting data that had been subject to incorrect calibration, and did not remove annual trends in mean radiation levels

Effect of Concave Wall Geometry on Heat Transfer in Hypersonic Boundary Layers

Heat transfer measurements are made to investigate the effects of concave surface curvature on a high-stagnation enthalpy boundary layer in a Mach 5.1 flow. Experiments are carried out using two curved models with 16 and 25 degree turning angles, and baseline planar models (at plate and linear ramp) for comparative study. Streamwise and spanwise cross-sections are obtained. Significant destabilization of the boundary layer is observed over the adverse pressure gradient geometries. For the curved surfaces, the heat flux distribution appears to exhibit a quadratic dependence with streamwise distance, in contrast with the linear dependence observed on the linear ramp

Generation and mobility of radon in soil. Technical report

This study has confirmed large seasonal and daily variations of Rn in soil gas, developed models for the effects of temperature and moisture on air-water Rn partition, inhibited Rn diffusion from wet soil into sparse large air-filled pores and effects of diffusion into bedrock, demonstrated that organic matter is a major host for 226Ra in soils and that organic-bound Ra largely determines the proportion of 222Rn emanated to pore space, shown that in contrast 220Rn is emanated mainly from 224Ra in Fe-oxides, detected significant disequilibrium between 226Ra and 238U in organic matter and in some recent glacial soils, demonstrated by computer models that air convection driven by temperature differences is expected in moderately permeable soils on hillsides

EQIP\u27s First Year: A Step Closer to Higher Quality in Surgical Education.

OBJECTIVE: To describe the first year of the Educational Quality Improvement Program (EQIP) DESIGN: The Educational Quality Improvement Program (EQIP) was formed by the Association of Program Directors in Surgery (APDS) in 2018 as a continuous educational quality improvement program. Over 18 months, thirteen discrete goals for the establishment of EQIP were refined and executed through a collaborative effort involving leaders in surgical education. Alpha and beta pilots were conducted to refine the data queries and collection processes. A highly-secure, doubly-deidentified database was created for the ingestion of resident and program data. SETTING & PARTICIPANTS: 36 surgical training programs with 1264 trainees and 1500 faculty members were included in the dataset. 51,516 ERAS applications to programs were also included. Uni- and multi-variable analysis was then conducted. RESULTS: EQIP was successfully deployed within the timeline described in 2020. Data from the ACGME, ABS, and ERAS were merged with manually entered data by programs and successfully ingested into the EQIP database. Interactive dashboards have been constructed for use by programs to compare to the national cohort. Risk-adjusted multivariable analysis suggests that increased time in a technical skills lab was associated with increased success on the ABS\u27s Qualifying Examination, alone. Increased time in a technical skills lab and the presence of a formal teaching curriculum were associated with increased success on both the ABS\u27s Qualifying and Certifying Examination. Program type may be of some consequence in predicting success on the Qualifying Examination. CONCLUSIONS: The APDS has proved the concept that a highly secure database for the purpose of continuous risk-adjusted quality improvement in surgical education can be successfully deployed. EQIP will continue to improve and hopes to include an increasing number of programs as the barriers to participation are overcome

Mineralogical Transformations and Soil Development in Shale Across a Latitudinal Climosequence

To investigate factors controlling soil formation, we established a climosequence as part of the Susquehanna-Shale Hills Critical Zone Observatory (SSHCZO) in central Pennsylvania, USA. Sites were located on organic matter-poor, iron-rich Silurian-aged shale in Wales, Pennsylvania, Virginia, Tennessee, Alabama, and Puerto Rico, although this last site is underlain by a younger shale. Across the climosequence, mean annual temperature (MAT) increases from 7 to 24°C and mean annual precipitation (MAP) ranges from 100 to 250 cm. Variations in soil characteristics along the climosequence, including depth, morphology, particle-size distribution, geochemistry, and bulk and clay mineralogy, were characterized to investigate the role of climate in controlling mineral transformations and soil formation. Overall, soil horizonation, depth, clay content, and chemical depletion increase with increasing temperature and precipitation, consistent with enhanced soil development and weathering processes in warmer and wetter locations. Secondary minerals are present at higher concentrations at the warmest sites of the climosequence; kaolinite increases from \u3c5% at northern sites in Wales and Pennsylvania to 30% in Puerto Rico. The deepest observed weathering reaction is plagioclase feldspar dissolution followed by the transformation of chlorite and illite to vermiculite and hydroxy-interlayered vermiculite. Plagioclase, although constituting \u3c12% of the initial shale mineralogy, may be the profile initiating reaction that begins shale bedrock transformation to weathered regolith. Weathering of the more abundant chlorite and illite minerals (∼70% of initial mineralogy), however, are more likely controlling regolith thickness. Climate appears to play a central role in driving soil formation and mineral weathering reactions across the climosequence

Individual tree and stand-level carbon and nutrient contents across one rotation of loblolly pine plantations on a reclaimed surface mine

While reclaimed loblolly pine (Pinus taeda L.) plantations in east Texas, USA have demonstrated similar aboveground productivity levels relative to unmined forests, there is interest in assessing carbon (C) and nutrients in aboveground components of reclaimed trees. Numerous studies have previously documented aboveground biomass, C, and nutrient contents in loblolly pine plantations; however, similar data have not been collected on mined lands. We investigated C, N, P, K, Ca, and Mg aboveground contents for first-rotation loblolly pine growing on reclaimed mined lands in the Gulf Coastal Plain over a 32-year chronosequence and correlated elemental rates to stand age, stem growth, and similar data for unmined lands. At the individual tree level, we evaluated elemental contents in aboveground biomass components using tree size, age, and site index as predictor variables. At the stand-level, we then scaled individual tree C and nutrients and fit a model to determine the sensitivity of aboveground elemental contents to stand age and site index. Our data suggest that aboveground C and nutrients in loblolly pine on mined lands exceed or follow similar trends to data for unmined pine plantations derived from the literature. Diameter and height were the best predictors of individual tree stem C and nutrient contents (R ≥ 0.9473 and 0.9280, respectively) followed by stand age (R ≥ 0.8660). Foliage produced weaker relationships across all predictor variables compared to stem, though still significant (P ≤ 0.05). The model for estimating stand-level C and nutrients using stand age provided a good fit, indicating that contents aggrade over time predictably. Results of this study show successful modelling of reclaimed loblolly pine aboveground C and nutrients, and suggest elemental cycling is comparable to unmined lands, thus providing applicability of our model to related systems