Benchmark of different aerodynamic solvers on wing aero-propulsive interactions

Distributed electric propulsion is a fertile research topic aiming to increase the wing aerodynamic efficiency by distributing the thrust over the wing span. The blowing due to distributed propulsors shall increase the wing lift coefficient for a given planform area and flight speed. This should bring several advantages as wing area, drag, and structural weight reduction, which in turn reduce fuel consumption, allowing airplanes to fly more efficiently. However, there are no consolidated preliminary design methods to size a distributed propulsion system. Numerical analysis is then performed at early stage, where many design variables have not been fixed yet. Therefore, the design space is vast and exploring all the possible combinations is unfeasible. For instance, low-fidelity methods (VLM, panel codes) have a low computational time, but usually they do not account for flow separation and hence they are unable to predict the wing maximum lift. Conversely, high-fidelity codes (CFD) provide more realistic results, but a single drag polar sweep can last days. This work provides a benchmark of different aerodynamic solvers for a typical regional turboprop wing with flaps and distributed propulsion, to better understand the limits of each software in the prediction of aero-propulsive effects

Similarity Maximization of a Scaled Aeroelastic Flight Demonstrator via Multidisciplinary Optimization

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143025/1/6.2017-0573.pd

Effect of Charcoal Earth Kilns Construction and Firing on Soil Chemical Characteristics

Assessments of localized ecological and environmental impacts of charcoal production including effects on soils at kiln sites is seldom undertaken, with more emphasis being placed on the global effects of the practice such as forest degradation and deforestation. A study was undertaken in Narok, Eldoret, Moiben, and Turbo in Kenya on known charcoaling sites to investigate the impact of charcoal production on the soil chemical characteristics. Composite soil samples from 12 sampling points for all study sites were taken randomly at a depth of 0–15 cm. The samples were conditioned and analyzed for pH, particle size, Cation Exchange Capacity (CEC), extractable phosphorus, organic carbon, nitrogen, and exchangeable bases. A comparison of the soil properties between undisturbed sites and charcoaling sites showed significant differences for all chemical properties except CEC, Mg, and K. For the Moiben site, only the pH showed no significant difference (p < 0.05).  The observed high carbon content reduced with time for the one year following charcoaling activity and was attributed to soil erosion since charcoal production activities reduced the sites vegetation cover. Most chemical changes positively enhanced the nutrients content and availability, but were short lived probably due to soil erosion.  These results demonstrate the need to adopt technologies with minimum impact on the soil, or a shift to centralized production sites outside forest ecosystems or farmlands.

Audit of the appropriateness of the indication for obstetric sonography in a tertiary facility in Ghana

Introduction: the use of ultrasound is one of the most vital tools in the management of pregnancies and contributes significantly in improving maternal and child health. Certain indications in pregnancy, guide the obstetrician as to which obstetric scan deems appropriate. The full realization of the benefits of ultrasound depends on whether it is being used appropriately or not, and hence this study aimed at auditing for the appropriate indications for obstetric ultrasound. Methods: a review of all request forms for obstetric scan between June 2019 and July 2020 was performed to assess the appropriateness of requests for obstetric ultrasound at the Cape Coast Teaching Hospital. The data obtained was analyzed using SPSS (SPSS Inc. Chicago, IL version 20.0). A Chi-squared test of independence was used to check for statistically significant differences between variables at p ≤ 0.05. Results: three hundred and fourteen (314) out of the 527 request forms had clinical indications stated. 174 (81.7%) of requests from Cape Coast Teaching Hospital and 39 (18.3%) from other health centers did not indicate patients clinical history/indication on the request forms. Majority 76 (68.5%) of scans in the first trimester were done without indications/history. Only 29 of requests with clinical history were inappropriate. Conclusion: practitioners should be mindful of adequately completing request forms for obstetric investigations since e a large number of practitioners do not state the history/indications for the scans. There should be continuous medical education on the importance of appropriate indication for obstetric ultrasound

Challenges with using primer IDs to improve accuracy of next generation sequencing

Next generation sequencing technologies, like ultra-deep pyrosequencing (UDPS), allows detailed investigation of complex populations, like RNA viruses, but its utility is limited by errors introduced during sample preparation and sequencing. By tagging each individual cDNA molecule with barcodes, referred to as Primer IDs, before PCR and sequencing these errors could theoretically be removed. Here we evaluated the Primer ID methodology on 257,846 UDPS reads generated from a HIV-1 SG3Δenv plasmid clone and plasma samples from three HIV-infected patients. The Primer ID consisted of 11 randomized nucleotides, 4,194,304 combinations, in the primer for cDNA synthesis that introduced a unique sequence tag into each cDNA molecule. Consensus template sequences were constructed for reads with Primer IDs that were observed three or more times. Despite high numbers of input template molecules, the number of consensus template sequences was low. With 10,000 input molecules for the clone as few as 97 consensus template sequences were obtained due to highly skewed frequency of resampling. Furthermore, the number of sequenced templates was overestimated due to PCR errors in the Primer IDs. Finally, some consensus template sequences were erroneous due to hotspots for UDPS errors. The Primer ID methodology has the potential to provide highly accurate deep sequencing. However, it is important to be aware that there are remaining challenges with the methodology. In particular it is important to find ways to obtain a more even frequency of resampling of template molecules as well as to identify and remove artefactual consensus template sequences that have been generated by PCR errors in the Primer IDs

Effect of Charcoal Earth Kilns Construction and Firing on Soil Chemical Characteristics

Assessments of localized ecological and environmental impacts of charcoal production including effects on soils at kiln sites is seldom undertaken, with more emphasis being placed on the global effects of the practice such as forest degradation and deforestation. A study was undertaken in Narok, Eldoret, Moiben, and Turbo in Kenya on known charcoaling sites to investigate the impact of charcoal production on the soil chemical characteristics. Composite soil samples from 12 sampling points for all study sites were taken randomly at a depth of 0–15 cm. The samples were conditioned and analyzed for pH, particle size, Cation Exchange Capacity (CEC), extractable phosphorus, organic carbon, nitrogen, and exchangeable bases. A comparison of the soil properties between undisturbed sites and charcoaling sites showed significant differences for all chemical properties except CEC, Mg, and K. For the Moiben site, only the pH showed no significant difference (p < 0.05).  The observed high carbon content reduced with time for the one year following charcoaling activity and was attributed to soil erosion since charcoal production activities reduced the sites vegetation cover. Most chemical changes positively enhanced the nutrients content and availability, but were short lived probably due to soil erosion.  These results demonstrate the need to adopt technologies with minimum impact on the soil, or a shift to centralized production sites outside forest ecosystems or farmlands.

Computed tomography features of spontaneous acute intracranial hemorrhages in a tertiary hospital in Southern Ghana

Introduction: spontaneous acute intracranial hemorrhage (SICH) accounts for approximately 10-15% of all stroke cases. Early detection by computed tomography (CT) and early treatment are key. Hence this study to examine the CT features of SICH. Methods: this retrospective cohort study reviewed all 435 patients diagnosed with SICH from 1st March, 2017 to 1st January, 2021 in a tertiary facility in Southern Ghana. Data collected (age, sex, SICH type and the CT scan features) were organized and analyzed using GNU PSPP and Libre Office Calc. Statistical significance level was pegged at p≤0.05. Results: the SICH types were acute intracerebral hemorrhage (97.93%), acute subarachnoid/intraventricular hemorrhage (1.15%), acute epidural hemorrhage (0.46%) and acute subdural hemorrhage (0.46%). Acute intracerebral hemorrhage was more common in those >60 years (57.75%, p<0.001). The commonest CT feature for acute intracerebral hemorrhage was hyperdense lesion with perilesional edema (40.98%), with smoking (OR=2.24, 95% CI: 1.14-4.41, p=0.019) and anticoagulants intake (OR=2.56, 95% CI: 1.15-5.72, p=0.022) as the predictive factors; followed by hyperdense lesion extending to the edge of the brain (25.03%), also predictable by smoking (OR=0.23, 95% CI: 0.11-0.47, p<0.001); and hyperdense lesion with mass effects (22.70%) was not predictive with any risk factor. Type 2 diabetes mellitus (60.00%, p<0.001) and smoking (97.83%, p<0.001) were more common in males. Conclusion: hyperdense lesion with perilesional edema was the most frequent CT feature for acute intracerebral hemorrhage and was predictable by smoking and anticoagulants intake. Smoking was a predictive factor to the development of most of the features of acute intracerebral hemorrhage

Weighing stars from birth to death: mass determination methods across the HRD

The mass of a star is the most fundamental parameter for its structure, evolution, and final fate. It is particularly important for any kind of stellar archaeology and characterization of exoplanets. There exists a variety of methods in astronomy to estimate or determine it. In this review we present a significant number of such methods, beginning with the most direct and model-independent approach using detached eclipsing binaries. We then move to more indirect and model-dependent methods, such as the quite commonly used isochrone or stellar track fitting. The arrival of quantitative asteroseismology has opened a completely new approach to determine stellar masses and to complement and improve the accuracy of other methods. We include methods for different evolutionary stages, from the pre-main sequence to evolved (super)giants and final remnants. For all methods uncertainties and restrictions will be discussed. We provide lists of altogether more than 200 benchmark stars with relative mass accuracies between $[0.3,2]\%$ for the covered mass range of M\in [0.1,16]\,\msun, $75\%$ of which are stars burning hydrogen in their core and the other $25\%$ covering all other evolved stages. We close with a recommendation how to combine various methods to arrive at a "mass-ladder" for stars.Comment: Invited review article for The Astronomy and Astrophysics Review. 146 pages, 16 figures, 11 tables. Accepted version by the Journal. It includes summary figure of accuracy/precision of methods for mass ranges and summary table for individual method

Weighing stars from birth to death : mass determination methods across the HRD

Funding: C.A., J.S.G.M., and M.G.P. received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 670519: MAMSIE). N.B. gratefully acknowledge financial support from the Royal Society (University Research Fellowships) and from the European Research Council (ERC-CoG-646928, Multi-Pop).The mass of a star is the most fundamental parameter for its structure, evolution, and final fate. It is particularly important for any kind of stellar archaeology and characterization of exoplanets. There exist a variety of methods in astronomy to estimate or determine it. In this review we present a significant number of such methods, beginning with the most direct and model-independent approach using detached eclipsing binaries. We then move to more indirect and model-dependent methods, such as the quite commonly used isochrone or stellar track fitting. The arrival of quantitative asteroseismology has opened a completely new approach to determine stellar masses and to complement and improve the accuracy of other methods. We include methods for different evolutionary stages, from the pre-main sequence to evolved (super)giants and final remnants. For all methods uncertainties and restrictions will be discussed. We provide lists of altogether more than 200 benchmark stars with relative mass accuracies between [0.3 ,2 ]% for the covered mass range of M ∈[0.1 ,16 ] M⊙ , 75 % of which are stars burning hydrogen in their core and the other 25 % covering all other evolved stages. We close with a recommendation how to combine various methods to arrive at a "mass-ladder" for stars.PostprintPeer reviewe