48 research outputs found

    Session 2: \u3cem\u3eThe Effect of Boom Leveling on Spray Dispersion\u3c/em\u3e

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    Self-propelled sprayers are commonly used in agriculture to disperse agrichemicals. These sprayers commonly have two boom wings with dozens of nozzles that disperse the chemicals. Automatic boom height systems reduce the variability of agricultural sprayer boom height, which is important to reduce uneven spray dispersion if the boom is not at the target height. A computational model was created to simulate the spray dispersion under the following conditions: a) one stationary nozzle based on the measured spray pattern from one nozzle, b) one stationary model due to an angled boom, c) superposition of multiple stationary nozzles due an angled boom, and d) superposition of multiple nozzles given the inputs of measured boom heights and the position of the sprayer over a field in time. The effect of boom leveling on spray dispersion was compared for three boom leveling systems on two sprayers (Systems A and B on a John Deere R4045, Systems B and C on an AGCO RoGator 1100C). For each boom leveling system, the measured boom height and sprayer position in time for one run was used (medium terrain course at 26 kph (16 mph)) [Burgers et al. Appl. Eng. Agric. 2021]. For each run, a coverage map was calculated with the measured boom heights and a reference level boom; the spray application error was calculated as the difference between them. The area for which the application error was less than 10% was 34.4 and 56.6% for Systems A and B on the R4045, respectively, and 45.0 and 59.3% for Systems C and B on the RoGator, respectively. This model can be used to quantify and compare coverage maps from boom leveling systems

    Analysis of cell-biomaterial interaction through cellular bridge formation in the interface between hGMSCs and CaP bioceramics

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    The combination of biomaterials and stem cells for clinical applications constitute a great challenge in bone tissue engineering. Hence, cellular networks derived from cells-biomaterials crosstalk have a profound influence on cell behaviour and communication, preceding proliferation and differentiation. The purpose of this study was to investigate in vitro cellular networks derived from human gingival mesenchymal stem cells (hGMSCs) and calcium phosphate (CaP) bioceramic interaction. Biological performance of CaP bioceramic and hGMSCs interaction was evaluated through cell adhesion and distribution, cellular proliferation, and potential osteogenic differentiation, at three different times: 5 h, 1 week and 4 weeks. Results confirmed that hGMSCs met the required MSCs criteria while displaying osteogenic differentiaton capacities. We found a significant increase of cellular numbers and proliferation levels. Also, protein and mRNA OPN expression were upregulated in cells cultured with CaP bioceramic by day 21, suggesting an osteoinductible effect of the CaP bioceramic on hGMSCs. Remarkably, CaP bioceramic aggregations were obtained through hGMSCs bridges, suggesting the in vitro potential of macrostructures formation. We conclude that hGMSCs and CaP bioceramics with micro and macropores support hGMSC adhesion, proliferation and osteogenic differentiation. Our results suggest that investigations focused on the interface cells-biomaterials are essential for bone tissue regenerative therapies

    Pedal underwater motion triggers highly-peaked resonance on water waves

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    Pedal wavemakers that generate surface gravity waves through bed orbital motion have been shown to produce particle-excursion patterns that mimic deep-water wave behaviour but in finite-depth channels. In this article, we report that gravity waves in a general viscous fluid can resonate through the action of pedal wavemakers. We analyse the linear response of waves in an infinite channel in terms of the displacement amplitude, frequency, and wavelength of the bottom action. We show that the system behaves as a long-pass filter in space and a high-pass filter in time with a sharp resonance affected by viscosity. Furthermore, we propose a protocol to design deep gravity waves with an on-demand wavelength in a finite-depth water channel. Our theoretical framework agrees with numerical simulations using Smoothed Particle Hydrodynamics. Our results thus quantify the performance of pedal wavemakers and provide essential formulas for industrial and computational applications of the pedal wavemaking technique, useful both in hydraulics and coastal engineering problems.Comment: 17 pages, 5 figure

    Mice with a Heterozygous Lrp6 Deletion Have Impaired Fracture Healing

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    Bone fracture non-unions, the failure of a fracture to heal, occur in 10%–20% of fractures and are a costly and debilitating clinical problem. The Wnt/ÎČ-catenin pathway is critical in bone development and fracture healing. Polymorphisms of linking low-density lipoprotein receptor-related protein 6 (LRP6), a Wnt-binding receptor, have been associated with decreased bone mineral density and fragility fractures, although this remains controversial. Mice with a homozygous deletion of Lrp6 have severe skeletal abnormalities and are not viable, whereas mice with a heterozygous deletion have a combinatory effect with Lrp5 to decrease bone mineral density. As fracture healing closely models embryonic skeletal development, we investigated the process of fracture healing in mice heterozygous for Lrp6 (Lrp6+/−) and hypothesized that the heterozygous deletion of Lrp6 would impair fracture healing. Mid-diaphyseal femur fractures were induced in Lrp6+/− mice and wild-type controls (Lrp6+/+). Fractures were analyzed using micro-computed tomography (ÎŒCT) scans, biomechanical testing, and histological analysis. Lrp6+/− mice had significantly decreased stiffness and strength at 28 days post fracture (PF) and significantly decreased BV/TV, total density, immature bone density, and mature area within the callus on day-14 and -21 PF; they had significantly increased empty callus area at days 14 and 21 PF. Our results demonstrate that the heterozygous deletion of Lrp6 impairs fracture healing, which suggests that Lrp6 has a role in fracture healing

    Neutronic design for ESS-Bilbao neutron source

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    The European Spallation Source-Bilbao (ESS-Bilbao) project plans to build an accelerator facility compliant with the ESS-AB requirements which will be able to drive several experimental stations for research purposes involving intense proton beams with currents up to 75 mA, 50 MeV of final energy, 1.5 ms of pulse length and up to 50 Hz repetition rate. The accelerator will also drive a compact neutron source which will provide useful neutron beams to carry out experiments on moderator optimization, neutron optics devices and general neutron instrumentation as well as preparation work for experiments to be carried out by neutron beam users at the large facilities

    Conceptual design of the beryllium rotating target for the ESS-Bilbao facility

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    The ESS-Bilbao facility, hosted by the University of the Basque Country (UPV/EHU), envisages the operation of a high-current proton accelerator delivering beams with energies up to 50 MeV. The time-averaged proton current will be 2.25 mA, delivered by 1.5 ms proton pulses with a repetition rate of 20 Hz. This beam will feed a neutron source based upon the Be (p,n) reaction, which will enable the provision of relevant neutron experimentation capabilities. The neutron source baseline concept consists in a rotating beryllium target cooled by water. The target structure will comprise a rotatable disk made of 6061-T6 aluminium alloy holding 20 beryllium plates. Heat dissipation from the target relies upon a distribution of coolant-flow channels. The practical implementation of such a concept is here described with emphasis put on the beryllium plates thermo-mechanical optimization, the chosen coolant distribution system as well as the mechanical behavior of the assembly

    Neutronic analysis of the bi-spectral moderator such as that proposed for ESS

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    This paper reports on design studies concerning a moderator concept which aims to maximize the time averaged flux. The idea is to provide neutron spectra showing two clear maxima, with peaks at View the MathML source and View the MathML source arising from leakage from both cryogenic and thermal moderators. Such a concept known as a bi-spectral moderator (Mezei, 2006 [1]) while proven on a reactor source has only been examined for the ESS 2003 proposal. Filges et al. (2003 [2]), which featured a different design than the current ESS. This paper thus reports on a baseline design for such a moderator concept and shows that it can provide substantial gains in count rates for those applications not requiring high resolution in time-of-flight

    Association between long term exposure to particulate matter and incident hypertension in Spain

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    Exposure to air particulate matter has been linked with hypertension and blood pressure levels. The metabolic risks of air pollution could vary according to the specific characteristics of each area, and has not been sufficiently evaluated in Spain. We analyzed 1103 individuals, participants in a Spanish nationwide population based cohort study ([email protected]), who were free of hypertension at baseline (2008-2010) and completed a follow-up exam of the cohort (2016-2017). Cohort participants were assigned air pollution concentrations for particulate matter < 10 mu m (PM10) and < 2.5 mu m (PM2.5) during follow-up (2008-2016) obtained through modeling combined with measurements taken at air quality stations (CHIMERE chemistry-transport model). Mean and SD concentrations of PM10 and PM2.5 were 20.17 +/- 3.91 mu g/m(3) and 10.83 +/- 2.08 mu g/m(3) respectively. During follow-up 282 cases of incident hypertension were recorded. In the fully adjusted model, compared with the lowest quartile of PM10, the multivariate weighted ORs (95% CIs) for developing hypertension with increasing PM10 exposures were 0.82 (0.59-1.14), 1.28 (0.93-1.78) and 1.45 (1.05-2.01) in quartile 2, 3 and 4 respectively (p for a trend of 0.003). The corresponding weighted ORs according to PM2.5 exposures were 0.80 (0.57-1.13), 1.11 (0.80-1.53) and 1.48 (1.09-2.00) (p for trend 0.004). For each 5-mu g/m(3) increment in PM10 and PM2.5 concentrations, the odds for incident hypertension increased 1.22 (1.06-1.41) p = 0.007 and 1.39 (1.07-1.81) p = 0.02 respectively. In conclusion, our study contributes to assessing the impact of particulate pollution on the incidence of hypertension in Spain, reinforcing the need for improving air quality as much as possible in order to decrease the risk of cardiometabolic disease in the population

    Association between exposure to air pollution and blood lipids in the general population of Spain.

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    Background and Aims: We aimed to assess the associations of exposure to air pollutants and standard and advanced lipoprotein measures, in a nationwide sample representative of the adult population of Spain.Methods: We included 4647 adults (>18 years), participants in the national, cross- sectional, population- based [email protected] study, conducted in 2008– 2010. Standard lipid measurements were analysed on an Architect C8000 Analyzer (Abbott Laboratories SA). Lipoprotein analysis was made by an advanced 1H- NMR lipoprotein test (LiposcaleÂź). Participants were assigned air pollution con-centrations for particulate matter <10 ÎŒm (PM10), <2.5 ÎŒm (PM2.5) and nitrogen dioxide (NO2), corresponding to the health examination year, obtained by mod-elling combined with measurements taken at air quality stations (CHIMERE chemistry- transport model).Results: In multivariate linear regression models, each IQR increase in PM10, PM2.5 and NO2 was associated with 3.3%, 3.3% and 3% lower levels of HDL- c and 1.3%, 1.4% and 1.1% lower HDL particle (HDL- p) concentrations (p< .001 for all associations). In multivariate logistic regression, there was a significant associa-tion between PM10, PM2.5 and NO2 concentrations and the odds of presenting low HDL- c (<40 mg/dL), low HDL- p (<p25) and higher LDL particle (LDL- p) concentrations (≄p75). In subgroup analyses there were stronger associations be-tween PM10 and NO2 and low HDL- p in men (p for interaction .008 and .034), and between NO2 and low HDL- p in individuals with obesity (p for interaction .015).Conclusions: Our study shows an association between the exposure to air pol-lutants and blood lipids in the general population of Spain, suggesting a link to atherosclerosisFunding for open access charge: Universidad de MĂĄlaga / CBU
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