442 research outputs found
Online Optimal Neuro-Fuzzy Flux Controller for DTC Based Induction Motor Drives
In this paper a fast flux search controller based on the Neuro-fuzzy systems is proposed to achieve the best efficiency of a direct torque controlled induction motor at light load. In this method the reference flux value is determined through a minimization algorithm with stator current as objective function. This paper discusses and demonstrates the application of Neurofuzzy filtering to stator current estimation. Simulation and experimental results are presented to show the fast response of proposed controller
Mitigating the Inrush Current of V/V Transformers using Railway Conditioners
Inrush current is high-magnitude current drawn by power transformers upon energization. The severity of inrush current depends on factors such as the transformer’s residual flux and the voltage phase angle at the energization instant. This paper proposes a flux matching method for the energization of V/V traction transformers to mitigate inrush current. This is achieved by adjusting the residual flux of the core to an appropriate reference value and then obtaining the proper energization instant. To this end, the method only requires knowledge of nominal voltage and excitation current, eliminating the need to acquire transformer’s parameters/design information. The railway power conditioner, typically present at the low voltage side of the V/V transformer, is used as a current source to inject sinusoidal current into the transformer windings before its energization. The reference residual flux is calculated based on the circuit breaker operating characteristics. The energization instant is determined such that the adjusted flux density matches the steady-state flux expected with respect to the applied voltage. The proposed method is validated by conducting over 14,000 simulations under different conditions using PSCAD/EMTDC. The method is also implemented and successfully tested on a laboratory-scale test rig, which verifies its effectiveness in more realistic conditions
Bis(phenylsulfinyl)methane
Two independent molecules comprise the asymmetric unit of the title compound, C13H12O2S2, which differ in terms of minor variations in the relative orientations of the benzene rings [the O–S–C–C torsion angles for the first independent molecule are −6.66 (17) and −12.88 (19)° compared with −21.70 (18) and 4.83 (16)° for the second molecule]. Supramolecular chains sustained by C—H⋯O contacts and aligned along the a axis are found in the crystal structure. These are held in place in the three dimensional structure by C—H⋯π interactions
Synergistic Antibacterial Effects of Metallic Nanoparticle Combinations
© The Author(s) 2019.Metallic nanoparticles have unique antimicrobial properties that make them suitable for use within medical and pharmaceutical devices to prevent the spread of infection in healthcare. The use of nanoparticles in healthcare is on the increase with silver being used in many devices. However, not all metallic nanoparticles can target and kill all disease-causing bacteria. To overcome this, a combination of several different metallic nanoparticles were used in this study to compare effects of multiple metallic nanoparticles when in combination than when used singly, as single elemental nanoparticles (SENPs), against two common hospital acquired pathogens (Staphylococcus aureus and Pseudomonas. aeruginosa). Flow cytometry LIVE/DEAD assay was used to determine rates of cell death within a bacterial population when exposed to the nanoparticles. Results were analysed using linear models to compare effectiveness of three different metallic nanoparticles, tungsten carbide (WC), silver (Ag) and copper (Cu), in combination and separately. Results show that when the nanoparticles are placed in combination (NPCs), antimicrobial effects significantly increase than when compared with SENPs (P < 0.01). This study demonstrates that certain metallic nanoparticles can be used in combination to improve the antimicrobial efficiency in destroying morphologically distinct pathogens within the healthcare and pharmaceutical industry.Peer reviewe
Effect of aminophylline in preventing renal dysfunction among neonates with prenatal asphyxia: A clinical trial
Background: As there are different views on the effects of aminophylline on neonatal renal function, we intended to observe the effects of aminophylline on renal dysfunction in neonates with prenatal asphyxia. Methods: This randomized trial was conducted in the Obstetrics and Gynecology Hospital, Tehran, Iran, from June 2016 to May 2017, in neonates with moderate to severe asphyxia during birth. Fifty-six neonates were divided randomly into two groups. The intervention group received one dose of 5mg/kg slow intravenous aminophylline injection and the placebo group received 2 mL/kg of intravenous 10 solution of dextrose saline during the first hour of life. They were monitored and compared for renal functional indices, electrolytes, and complications of asphyxia during the three days of life. Results: The mean of Cr (37.9 ± 8.8 vs 38.5 ± 9.4 and 20.8 ± 4.8 vs 30.1 ± 5.2 μmol/L), GFR (21.55 ± 4.7 vs 20.25 ± 4.4 and 30.8 ± 7.1 vs 20.1 ± 6.5 mL/minute/1.73 m2), Na (135.1 ± 12.4 vs134.5 ± 11.2 and 128.9 ± 11.5 vs 134.2 ± 10.9 mEq/L), and urine output (98.2 ± 25 vs 96.8 ± 23 and 148.7 ± 35 vs 108.8 ± 20 cc) were in the aminophylline treated and placebo group on the 1st and 3rd days, respectively. The mean difference of Cr (-9.3 (-8.9; -9.7) μmol/L); (P = 0.02), GFR (10.7 (10.1; 11.3) mL/minute/1.73 m2) (P = 0.009), Na (-5.3 (-5.9; -4.7) mEq/L) (P = 0.002), and urine volume (39.9 (24.9; 54.9) cc) (P = 0.001) presented statistically significant differences on the third day between the intervention and placebo group. Conclusion: Aminophylline was effective in preventing renal dysfunction in neonates with asphyxia. Neonates who received aminophylline indicated a significant improvement in GFR and urine output on the first day of life. © 2020 The authors and IJLTER.ORG. All rights reserved
Correction: Disease-specific protein corona sensor arrays may have disease detection capacity
The DACAPO-PESO campaign: Dynamics, Aerosol, Cloud and Precipitation Observations in the Pristine Environment of the Southern Ocean: An overview
This article gives an overview of the DACAPO-PESO field experiment,
which has taken place in Punta Arenas, Chile, from November 2018 to November 2021,
and showcases first exciting research results that have already emerged from it.In diesem Artikel wird ein Überblick über das DACAPO-PESO
Experiment gegeben, welches von November 2018 bis November 2021 in Punta Arenas,
Chile, stattgefunden hat. Außerdem werden erste spannende Forschungsergebnisse
vorgestellt, die bereits daraus gewonnen wurden
Is salt intake reduction a universal intervention for both normotensive and hypertensive people: a case from Iran STEPS survey 2016
Purpose: There is a direct association between salt intake and blood pressure (BP), one of the main risk factors for CVDs. However, yet there has been a debate that how strong is this association in people with and without hypertension. This study was conducted to evaluate the magnitude of the association between salt intake and BP in hypertensive and normotensive population among a nationally representative population. Methods: The study was conducted on a nationally representative sample of 18,635 Iranian adults aged 25 years and older who participated in the STEPS survey 2016 and provided urine sample. Salt intake was estimated through spot urine sample and Tanaka equation. Multiple linear regression model in survey data analysis was used to assess the independent effect of salt intake on BP. Results: After adjusting for covariates, there was a significant association between salt intake and SBP in hypertensive (p ' 0.001) and normotensive people (p ' 0.001). In hypertensive people, with 1 g of increase in salt intake, the SBP and DBP increased 0.37 mmHg and 0.07 mmHg, respectively. Whereas in normotensive people, with 1 g of increase in salt intake, the SBP and DBP increased 0.26 mmHg and 0.05 mmHg, respectively. Moreover, there was a significant trend toward an increase of SBP across salt intake quartiles in both hypertensive (p ' 0.001) and normotensive people (p = 0.002), though the slope was steeper in hypertensive than in normotensive people. Conclusions: The present study demonstrated that salt intake significantly increased SBP in both hypertensive and normotensive people, though the magnitude of this increase was greater in hypertensive people as compared with normotensive people
Analytical protocols for separation and electron microscopy of nanoparticles interacting with bacterial cells
An important step toward understanding interactions between nanoparticles (NPs) and bacteria is the ability to directly observe NPs interacting with bacterial cells. NPbacteria mixtures typical in nanomedicine, however, are not yet amendable for direct imaging in solution. Instead, evidence of NPcell interactions must be preserved in derivative (usually dried) samples to be subsequently revealed in high-resolution images, e.g., via scanning electron microscopy (SEM). Here, this concept is realized for a mixed suspension of model NPs and Staphylococcus aureus bacteria. First, protocols for analyzing the relative colloidal stabilities of NPs and bacteria are developed and validated based on systematic centrifugation and comparison of colony forming unit (CFU) counting and optical density (OD) measurements. Rate-dependence of centrifugation efficiency for each component suggests differential sedimentation at a specific predicted rate as an effective method for removing free NPs after co-incubation; the remaining fraction comprises bacteria with any associated NPs and can be examined, e.g., by SEM, for evidence of NPbacteria interactions. These analytical protocols, validated by systematic control experiments and high-resolution SEM imaging, should be generally applicable for investigating NPbacteria interactions.financial support from the following sources:
grant SFRH/BPD/47693/2008 from the Portuguese Foundation for Science and Technology (FCT); FCT Strategic Project PEst-OE/EQB/LA0023/2013; project “BioHealth Biotechnology
and Bioengineering approaches to improve health quality”, Ref. NORTE-07-0124-FEDER-000027, cofunded by the Programa Operacional Regional do Norte (ON.2−O Novo
Norte), QREN, FEDER; project “Consolidating Research Expertise and Resources on Cellular and Molecular Biotechnology at CEB/IBB”, ref. FCOMP-01-0124-FEDER- 027462
An evaluation of three DoE-guided meta-heuristic-based solution methods for a three-echelon sustainable distribution network
This article evaluates the efficiency of three meta-heuristic optimiser (viz. MOGA-II, MOPSO and NSGA-II)-based solution methods for designing a sustainable three-echelon distribution network. The distribution network employs a bi-objective location-routing model. Due to the mathematically NP-hard nature of the model a multi-disciplinary optimisation commercial platform, modeFRONTIER®, is adopted to utilise the solution methods. The proposed Design of Experiment (DoE)-guided solution methods are of two phased that solve the NP-hard model to attain minimal total costs and total CO2 emission from transportation. Convergence of the optimisers are tested and compared. Ranking of the realistic results are examined using Pareto frontiers and the Technique for Order Preference by Similarity to Ideal Solution approach, followed by determination of the optimal transportation routes. A case of an Irish dairy processing industry’s three-echelon logistics network is considered to validate the solution methods. The results obtained through the proposed methods provide information on open/closed distribution centres (DCs), vehicle routing patterns connecting plants to DCs, open DCs to retailers and retailers to retailers, and number of trucks required in each route to transport the products. It is found that the DoE-guided NSGA-II optimiser based solution is more efficient when compared with the DoE-guided MOGA-II and MOPSO optimiser based solution methods in solving the bi-objective NP-hard three-echelon sustainable model. This efficient solution method enable managers to structure the physical distribution network on the demand side of a logistics network, minimising total cost and total CO2 emission from transportation while satisfying all operational constraints
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