Real Coded Mixed Integer Genetic Algorithm for Geometry Optimization of Flight Simulator Mechanism Based on Rotary Stewart Platform

Featured Application Low-cost flight simulators with electric rotary actuators and optimized geometry for flight simulation. Designing the motion platform for the flight simulator is closely coupled with the particular aircraft's flight envelope. While in training, the pilot on the motion platform has to experience the same feeling as in the aircraft. That means that flight simulators need to simulate all flight cases and forces acting upon the pilot during flight. Among many existing mechanisms, parallel mechanisms based on the Stewart platform are suitable because they have six degrees of freedom. In this paper, a real coded mixed integer genetic algorithm (RCMIGA) is applied for geometry optimization of the Stewart platform with rotary actuators (6-RUS) to design a mechanism with appropriate physical limitations of workspace and motion performances. The chosen algorithm proved that it can find the best global solution with all imposed constraints. At the same time, the obtained geometry can be manufactured because integer solutions can be mapped to available discrete values. Geometry is defined with a minimum number of parameters that fully define the mechanism with all constraints. These geometric parameters are then optimized to obtain custom-tailored geometry for aircraft flight simulation

High intensity interval training protects the heart during increased metabolic demand in patients with type 2 diabetes: a randomised controlled trial

AimThe present study assessed the effect of high intensity interval training on cardiac function during prolonged submaximal exercise in patients with type 2 diabetes.MethodsTwenty-six patients with type 2 diabetes were randomized to a 12 week of high intensity interval training (3 sessions/week) or standard care control group. All patients underwent prolonged (i.e. 60min) submaximal cardiopulmonary exercise testing (at 50% of previously assess maximal functional capacity) with non-invasive gas-exchange and haemodynamic measurements including cardiac output and stroke volume before and after the intervention.ResultsAt baseline (prior to intervention) there was no significant difference between the intervention and control group in peak exercise oxygen consumption (20.36.1 vs. 21.75.5ml/kg/min, p=0.21), and peak exercise heart rate (156.3 +/- 15.0 vs. 153.8 +/- 12.5 beats/min, p=0.28). During follow-up assessment both groups utilized similar amount of oxygen during prolonged submaximal exercise (15.0 +/- 2.4 vs. 15.2 +/- 2.2ml/min/kg, p=0.71). However, cardiac function i.e. cardiac output during submaximal exercise decreased significantly by 21% in exercise group (16.2 +/- 2.7-12.8 +/- 3.6L/min, p=0.03), but not in the control group (15.7 +/- 4.9-16.3 +/- 4.1L/min, p=0.12). Reduction in exercise cardiac output observed in the exercise group was due to a significant decrease in stroke volume by 13% (p=0.03) and heart rate by 9% (p=0.04).Conclusion Following high intensity interval training patients with type 2 diabetes demonstrate reduced cardiac output during prolonged submaximal cardiopulmonary exercise testing. Ability of patients to maintain prolonged increased metabolic demand but with reduced cardiac output suggests cardiac protective role of high intensity interval training in type 2 diabetes.Trial registration ISRCTN78698481. Registered 23 January 2013, retrospectively registered

Influence of Defects on the Stability and Hydrogen‐Sorption Behavior of Mg‐Based Hydrides

This review deals with the destabilization methods for improvement of storage properties of metal hydrides. Both theoretical and experimental approaches were used to point out the influence of various types of defects on structure and stability of hydrides. As a case study, Mg, and Ni based hydrides has been investigated. Theoretical studies, mainly carried out within various implementations of DFT, are a powerful tool to study mostly MgH 2 based materials. By providing an insight on metal-hydrogen bonding that governs both thermodynamics and hydrogen kinetics, they allow us to describe phenomena to which experimental methods have a limited access or do not have it at all: to follow the hydrogen sorption reaction on a specific metal surface and hydrogen induced phase transformations, to describe structure of phase boundaries or to explain the impact of defects or various additives on MgH 2 stability and hydrogen sorption kinetics. In several cases theoretical calculations reveal themselves as being able to predict new properties of materials, including the ways to modify Mg or MgH 2 that would lead to better characteristics in terms of hydrogen storage. The influence of ion irradiation and mechanical milling with and without additives has been discussed. Ion irradiation is the way to introduce a well-defined concentration of defects (Frankel pairs) at the surface and sub-surface layers of a material. Defects at the surface play the main role in sorption reaction since they enhance the dissociation of hydrogen. On the other hand, ball-milling introduce defects through the entire sample volume, refine the structure and thus decrease the path for hydrogen diffusion. Two Severe Plastic Deformation techniques were used to better understand the hydrogenation/dehydrogenation kinetics of Mg- and Mg 2 Ni-based alloys: Equal-Angular-Channel-Pressing and Fast-Forging. Successive ECAP passes leads to refinement of the microstructure of AZ31 ingots and to instalment therein of high densities of defects. Depending on mode, number and temperature of ECAP passes, the H-sorption kinetics have been improved satisfactorily without any additive for mass H-storage applications considering the relative speed of the shaping procedure. A qualitative understanding of the kinetic advanced principles has been built. Fast-Forging was used for a “quasi-instantaneous” synthesis of Mg/Mg 2 Ni-based composites. Hydrogenation of the as-received almost bi-phased materials remains rather slow as generally observed elsewhere, whatever are multiple and different techniques used to deliver the composite alloys. However, our preliminary results suggest that a synergic hydrogenation / dehydrogenation process should assist hydrogen transfers from Mg/Mg 2 Ni on one side to MgH 2 /Mg 2 NiH 4 on the other side via the rather stable a-Mg 2 NiH 0.3 , acting as in-situ catalyser. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, WeinheimThis is the peer reviewed version of the following article: Grbović Novaković, J., Novaković, N., Kurko, S., Milošević Govedarović, S., Pantić, T., Paskaš Mamula, B., ... & Skryabina, N. (2019). Influence of Defects on the Stability and Hydrogen‐Sorption Behavior of Mg‐Based Hydrides. ChemPhysChem., which has been published in final form at [http://dx.doi.org/10.1002/cphc.201801125]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions

LC/MS study of the UV filter hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]-benzoate (DHHB) aquatic chlorination with sodium hypochlorite.

International audienceThe fate of modern personal care products in the environment is becoming a matter of increasing concern because of the growing production and assortment of these compounds. More and more chemicals of this class are treated as emerging contaminants. Transformation of commercially available products in the environment may result in the formation of a wide array of their metabolites. Personal care products in swimming pools and in drinking water reservoirs may undergo oxidation or chlorination. There is much data on the formation of more toxic metabolites from original low toxicity commercial products. Therefore, reliable identification of all possible transformation products and a thorough study of their physicochemical and biological properties are of high priority. The present study deals with the identification of the products of the aquatic chlorination of the hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]-benzoate ultraviolet filter. High-performance liquid chromatography/mass spectrometry (HPLC/MS) and HPLC/MS/MS with accurate mass measurements were used for this purpose. As a result, three chlorinated transformation products were identified

Complex effect of Robinia pseudoacacia L. And ailanthus altissima (Mill.) Swingle growing on asbestos deposits: Allelopathy and biogeochemistry

© 2020 Serbian Chemical Society. All rights reserved. Asbestos is widely mined and used around the globe posing a great risk to environment and human health. The main objective of this study was to determine allelopathic potential of Robinia pseudoacacia L. and Ailanthus altissima (Mill.) Swingle growing on the asbestos deposits at abandoned mine Stragari in central Serbia. The pH, content of carbon, nitrogen, calcium carbonate, available phosphorous and potassium, content of Fe, Ni, Cu, Zn, Pb, Mn, and phenolics were analyzed in the control asbestos (zones without vegetation cover) and plant rhizospheric asbestos. Allelopathic activity of plant species was assessed by rhizosphere soil method, and Trifolium pratense L. and Medicago sativa L. were used as the indicator species. A. altissima showed higher allelopathic potential compared to R. pseudoacacia for T. pratense and M. sativa due to greater content of phenolics. Alleopathic activity of phenolics in rhizospheric asbestos was highly correlated with pH, content of carbon and nitrogen, available phosphate and potassium, and content of Ni, Cu, Zn, Pb and Mn. A. altissima increased phenolics content in rhizospheric asbestos inhibiting the plant growth. This woody plant in spite of high allelopathic potential is suitable for revegetation of distrurbed ecosystems because it initiates pedogenesis and affects the asbestos chemistry