High-Torque-Density Low-Cost Magnetic Gear Utilizing Hybrid Magnets and Advanced Materials

Two major challenges of existing high-performance magnetic gears are: (i) High content of rare-earth permanent magnets which results in high cost as well as price fluctuation; (ii) Conflict between mechanical and electromagnetic performances, especially in the design of highspeed rotor. A magnetic gear using a blend of magnet types, i.e NdFeB, or Dy-free NdFeB and ferrites, is proposed in this paper. The goal is to bring down the cost while retaining comparable torque-transducing performance to a baseline magnetic gear only using rare-earth NdFeB magnets. A variety of topologies based on different combinations of magnet types and geometric shapes have been studied and compared. In addition, the potential impact of using an advanced dual-phase material is evaluated. The goal is to eliminate the well-known tradeoff between rotor mechanical integrity and PM flux leakage

A Novel ??-Negative Metamaterial with Enhanced Rejection Bandwidth

Published by and copyright of Science Publications. The definitive version of this article is available at: http://thescipub.com/abstract/10.3844/ajeassp.2013.137.144In this study, a novel planar ??-Negative (MNG) metamaterial structure based on Split Ring Resonators\ud (SRRs) with improved rejection bandwidth is presented. A bridging technique is used to connect two SRR\ud unit cells at the center to emulate a cascaded filter. The proposed structure achieved a -20 dB rejection\ud bandwidth of 15.5% compared to 4.5% for the conventional SRRs which makes it a good candidate for\ud integration with antennas and RF circuits that require large operational bandwidth

Decoupled and Descattered Monopole MIMO Antenna Array with Orthogonal Radiation Patterns

This chapter introduces a novel design concept to reduce mutual coupling among closely-spaced antenna elements of a MIMO array. This design concept significantly reduces the complexity of traditional/existing design approaches such as metamaterials, defected ground plane structures, soft electromagnetic surfaces, parasitic elements, matching and decoupling networks using a simple, yet a novel design alternative. The approach is based on a planar single decoupling element, consisting of a rectangular metallic ring resonator printed on one face of an ungrounded substrate. The decoupling structure surrounds a two-element vertical monopole antenna array fed by a coplanar waveguide structure. The design is shown both by simulations and measurements to reduce the mutual coupling by at least 20 dB, maintain the impedance bandwidth over which S11, is less than −10 dB, and reduce the envelope correlation coefficient to below 0.001. The boresight of the far-field radiation patterns of the two vertical monopole wire antennas operating at 2.4 GHz and separated by 8 mm (λo/16), where λo is the free-space wavelength at 2.45 GHz, is shown to be orthogonal and inclined by 45° with respect to the horizontal (azimuthal) plane while maintaining the shape of the isolated single antenna element

Hyponatremia in hospitalized patients with chronic kidney disease; aetiology, treatment, and outcome, in a tertiary care hospital, Dubai, UAE

Background: Hyponatremia is common among hospitalized patients. Unfortunately, articles describing the management of profound hyponatremia (serum sodium <125 mEq/l) in the background of kidney disease are scarce. This review focuses on the incidence, prevalence, patient characteristics, and clinical features among hospitalized chronic kidney disease (CKD) patients with particular attention to CKD stage 3 to 5.Methods: 71 adult patients with CKD stage 3 to 5 and had presented with profound hyponatremia (serum sodium <125 mEq/l) were included. Patient demographic data, laboratory parameters and treatment received were recorded. The primary endpoint was the development of central nervous syste (CNS) manifestations, while the secondary outcomes included early mortality (death within 30 days).Results: 97 episodes of hyponatremia were recorded in 71 patients. 35 patients (49%) were UAE national and 53.5% patients were females. 52% were in CKD stage-5 refusing dialysis. Diabetic nephropathy was the underlying cause in 66%. The initial Sodium level upon admission ranged from 107-125 mEq/l, with a mean±standard deviation (SD) value of 117.7±4.54 mEq/l. The correction of hyponatremia had ranged between 24 hours in 60% of the patients to 96 hours. Diuretics were used in conjunction with the saline in 85%. Hospital stay ranged between 2-58 days (average 11.7 days). No CNS symptoms were recorded in any of the treated patients. Three patients had died (within 30 days) of sepsis of different sources.Conclusions: Management of hyponatremia in CKD patients remains challenging and should be directed to the underlying cause. Yet, complex patients with advanced CKD particularly in concurrence with heart failure might represent a medical dilemma. Administering hypertonic saline in different mixed concentrations depending on the volume status of the patients appear to be safe, efficient, and suitable for high-risk CKD patients while monitoring Sodium level carefully

Catalytic Reductive Degradation of Methyl Orange Using Air Resilient Copper Nanostructures

The study describes the application of oxidation resistant copper nanostructures as an efficient heterogeneous catalyst for the treatment of organic dye containing waste waters. Copper nanostructures were synthesized in an aqueous environment using modified surfactant assisted chemical reduction route. The synthesized nanostructures have been characterized by UV-Vis, Fourier transform infrared spectroscopy FTIR spectroscopy, Atomic force microscopy (AFM), Scanning Electron Microscopy (SEM), and X-ray diffractometry (XRD). These surfactant capped Cu nanostructures have been used as a heterogeneous catalyst for the comparative reductive degradation of methyl orange (MO) in the presence of sodium borohydride (NaBH4) used as a potential reductant. Copper nanoparticles (Cu NPs) were found to be more efficient compared to copper nanorods (Cu NRds) with the degradation reaction obeying pseudofirst order reaction kinetics. Shape dependent catalytic efficiency was further evaluated from activation energy (EA) of reductive degradation reaction. The more efficient Cu NPs were further employed for reductive degradation of real waste water samples containing dyes collected from the drain of different local textile industries situated in Hyderabad region, Pakistan

If current inhibitor ivabradine in patients with idiopathic dilated cardiomyopathy: Impact on the exercise tolerance and quality of life

Background: Evidence supported a beneficial effect of ivabradine on clinical outcome of patients with systolic heart failure, and a sinus heart rate (HR) ≥ 70 bpm. We explored the effect of ivabradine, vs. placebo, added to evidence-based treatment on exercise tolerance and quality of life in patients with idiopathic dilated cardiomyopathy. Methods: We enrolled 43 consecutive patients with dilated cardiomyopathy of no apparent cause, a left ventricular ejection fraction (LVEF) &lt; 40%, New York Heart Association class ≥ II, sinus HR ≥ 70 bpm, and background evidence-based anti-failure medications. Ischemic heart disease was ruled out. Patients were randomized (1:1) to receive ivabradine or placebo. Ivabradine was titrated up gradually till 7.5 mg twice daily, or a HR &lt; 60 bpm, and continued for 3 months. Symptom-limited exercise tolerance test was performed, and quality of life was assessed by the Minnesota Living With Heart Failure Questionnaire at 0, and 3 months. Results: Forty-three patients were randomized to ivabradine (n = 20), or placebo (n = 23). Mean age was 50.8 ± 14.5 years (53.5% males). Mean HR was 85 ± 12 bpm, and mean LVEF was 32 ± 6%. Mean dose of carvedilol was 31.2% of the target dose. Baseline HR, blood pressure, exercise tolerance, Minnesota questionnaire score, and left ventricular systolic function were comparable between the two groups (p &gt; 0.05 for all). At 3 months, mean dose of ivabradine was 6.8 mg bid. Ivabradine-treated patients had a lower HR, and improved left ventricular dimensions and systolic function, versus placebo-treated ones (p &lt; 0.05 for all). HR dropped by a mean of 14 bpm in the ivabradine group, corrected for placebo. Both exercise tolerance, and Minnesota questionnaire score were better in the ivabradine group (p &lt; 0.05 both). Ivabradine was well-tolerated. Conclusions: In symptomatic patients with idiopathic dilated cardiomyopathy, the addition of ivabradine, vs. placebo, to evidence-based treatment, reduced HR, and improved functional capacity, at short-term follow-up

Multi-octave, CEP-stable source for high-energy field synthesis

The development of high-energy, high-power, multi-octave light transients is currently the subject of intense research driven by emerging applications in attosecond spectroscopy and coherent control. We report on a phase-stable, multi-octave source based on a Yb:YAG amplifier for light transient generation. We demonstrate the amplification of a two-octave spectrum to 25 mu J of energy in two broadband amplification channels and their temporal compression to 6 and 18 fs at 1 and 2 mu m, respectively. In this scheme, due to the intrinsic temporal synchronization between the pump and seed pulses, the temporal jitter is restricted to long-term drift. We show that the intrinsic stability of the synthesizer allows subcycle detection of an electric field at 0.15 PHz. The complex electric field of the 0.15-PHz pulses and their free induction decay after interaction with water molecules are resolved by electro-optic sampling over 2 ps. The scheme is scalable in peak and average power

Effect of slow-release nitrogenous fertilizers on dry matter accumulation, grain nutritional quality, water productivity and wheat yield under an arid environment

Slow release nitrogenous fertilizers can improve crops production and reduce the environmental challenges in agro-ecosystem. There is a need to test the efficiency and performance under arid climatic conditions. The study investigates the effect of slow-release fertilizers (urea, neem coated urea (NCU), sulfur coated urea (SCU) and bioactive sulfur coated urea (BSCU)) on the growth, productivity and grain nutritional qualities of wheat crop. Slow-release fertilizers (SRF) with nitrogen levels (130,117,104 and 94 kg ha−1) were applied with equal splits at sowing, 20 and 60 days after sowing (DAS). Research showed that the BSCU with 130 kg ha−1 increased dry matter accumulation (1989 kg ha−1) after anthesis and grain yield 4463 kg ha−1. The higher plant height (102 cm) was attained by 130 kg N ha−1 SCU while the minimum (77.67 cm) recorded for 94 kg N ha−1 as urea source. Maximum grain NPK concentrations (3.54, 0.66 and 1.07%) were recorded by BSCU 130 kg N ha−1 application. While, the minimum NPK (0.77, 0.19 and 0.35%) were observed by Urea 94 kg N ha−1. The high irrigation water use efficiency (WUE) recorded (20.92 kg ha−1 mm−1) and a crop index of 25.52% by BSCU 130 kg N ha−1 application. Research findings show that generally all SRF but particularly BSCU proved effective and can be recommended for wheat crop under arid environmen