The present study focused on thermal conductivity and viscosity of alumina nanoparticles, at low volume concentrations of 0.01–1.0 % dispersed in the mixture of ethylene glycol and water (mass ratio, ...60:40). Sodium dodeobcylbenzene sulfonate (SDBS) was applied for better dispersion and stability of alumina nanoparticles and study of its influence on both thermal conductivity and viscosity. The thermal conductivity established polynomial enhancement pattern with increase of volume concentration up to 0.1 % while linear enhancement was obtained at higher concentrations. In addition, thermal conductivity was enhanced with the rise of temperature. However, the augmentation was negligible compared to that obtained with increase of volume concentration. In contrast, viscosity data showed remarkable reduction with increase of temperature. Meanwhile, viscosity of nanofluids enhanced with loading of alumina nanoparticles. Thermal conductivity and viscosity measurements showed higher values over theoretical predictions. Results showed SDBS at different concentrations has distinct influence on thermal conductivity and viscosity of nanofluid.
The problem of short term load forecasting (STLF) for power grids using the dynamic mode decomposition with control (DMDc) is considered. A forecasting model is discovered from time-series data based ...on the dynamic mode decomposition algorithm in which the effect of climatic factors on electric power consumption is considered. An input selection method is also proposed to provide more informative dataset that efficiently reflects the load pattern changes. The meteorological data are processed through a hierarchical clustering method and is used by the DMDc algorithm as the inputs. The forecasting results with three datasets from Electric Reliability Council of Texas, ISO New England, and Australian Energy Market Operator show the effective performance of the proposed method compared to several other well-known forecasting methods within the literature of STLF such as ARIMAX, SVR, and DMD. Specifically, the average daily load forecasting errors are 4.78%, 7.6%, and 3.94% for the load datasets of three companies which indicates an improvement of 21.64%, 15.55% and 10.45%, respectively, compared to the DMD method without considering the effect of the climatic factors.
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•Short term load forecasting using dynamic mode decomposition with control (DMDc) is studied.•Climatic data such as humidity are used to calculate the average real feel temperature.•The time-series load/temperature data are classified using hierarchical clustering technique to facilitate the input selection step.
Bell’s palsy is an idiopathic peripheral nerve palsy involving the facial nerve. It accounts for 60 to 75% of all cases of unilateral facial paralysis. The main mechanisms to induce BP remain ...unclear, but infection, ischemic condition and immunodeficiency may contribute to the development of Bell’s palsy. Accumulating evidence has shown several factors can trigger the reactivation of latent HSV including psychological stressors, physical stressors and immunosuppression. Ionization and non-ionization radiations are of importance of physical stressors. Some data have shown radiation can reactivate HSVs. Based on preliminary studies showing radiation reactivation of HSVs, we aimed to hypothesize radiation (in both forms of ionization and non-ionization) may cause Bell’s palsy. In the future, the role of radiotherapy, radiofrequency radiation from mobile phones and wireless devices in HSV reactivation and Bell’s palsy should be investigated.
The performance improvement of 905 nm InGaAs/AlGaAs/GaAs Single Quantum Well Separate-Confinement Heterostructure Laser Diode (SQW-SCH-LD) in consequence of three-step procedure for facet passivation ...and protection was demonstrated. Initially, processed InGaAs/AlGaAs/GaAs SQW-SCH LD wafer was scribed and cleaved in ambient atmosphere. Secondly, the air-exposed bar facets were cleaned and impurities were removed with Ar + irradiation and bombardment. Finally, after simulation, mirrors consist of single-layer Al2O3 as Low-Reflection (LR) and multilayer |(Al2O3/Si)4| as High-Reflection (HR) coatings were deposited on front and back facets, respectively. Mirror's surface and interface properties were investigated by UV-Vis-NIR Spectroscopy, Atomic Force Microscopy (AFM), Field Emission Scanning Electron Microscopy (FESEM), Burn-in test, Life-time test and Thermography. Spectrophotometer results of coated mirrors were in appropriate adaptation with the simulation results. High magnification FESEM images reveal the precise repeatability stacked Al2O3/Si 8-layers with amorphous structure on GaAs substrate. Thermographic image of front facet after life-time reveals that front mirror retains initial quality. In the case of coated front mirror and in Continues-Wave laser mode, laser induce damage threshold (LIDT) improved and increased up to >> 45.75 kW/cm2. Improvement in mirror coating process results in enhancement laser reliability and operational parameters such as increasing output power and power efficiency, decreasing degradation rate without any catastrophic optical mirror damage.
•A 3-step procedure was used to improve 905 nm high power laser diode reliability.•LR Al2O3 monolayer and HR (Al2O3/Si)4 multilayer mirrors simulated, coated and tested.•98.2% front mirror transmittance and 97.9% back mirror reflectance obtained at 905 nm.•CS-packaged LD show about 3000 h in ACC-mode life time without any COMD event.•250 W CW-laser at ~800 μm beam spot didn't damage front mirror (LIDT>> 45.75 KW/cm2).
Design of an optimal fuzzy scheme for a fuel cell/battery vehicle to control the power flow between the main components, i.e. the fuel cell, electric motor, and battery, under various driving ...conditions, is considered in this paper. For this purpose, firstly, the optimum sizes of the main components are calculated by means of a Particle Swarm Optimization (PSO) algorithm. Subsequently, a Fuzzy Logic Controller (FLC) is devised for the control of the power flow. Finally, the FLC is optimized for various driving patterns and an optimal control scheme, based on PSO application, is proposed for energy management of the Fuel Cell Vehicle (FCV) under various traffic conditions. In each one of the mentioned stages, the same optimization process is conducted by applying a Genetic Algorithm (GA) for comparison with the result of the PSO. The results of the computer simulation are compared over diverse driving conditions. The results give an acceptable indication of progress in fuel economy for various driving patterns, using the proposed optimal fuzzy controller.
High-stress Si\(_3\)N\(_4\) nanoresonators have become an attractive choice for electro- and optomechanical devices. Membrane resonators can achieve quality factor (\(Q\)) - frequency (\(f\)) ...products exceeding \(10^{13}\) Hz, enabling (in principle) quantum coherent operation at room temperature. String-like beam resonators possess conventionally 10 times smaller \(Q\cdot f\) products; however, on account of their much larger \(Q\)-to-mass ratio and reduced mode density, they remain a canonical choice for precision force, mass, and charge sensing, and have recently enabled Heisenberg-limited position measurements at cryogenic temperatures. Here we explore two techniques to enhance the \(Q\)-factor of a nanomechanical beam. The techniques relate to two main loss mechanisms: internal loss, which dominates for large aspect ratios and \(f\lesssim100\) MHz, and radiation loss, which dominates for small aspect ratios and \(f\gtrsim100\) MHz. First we show that by embedding a nanobeam in a 1D phononic crystal, it is possible to localize its flexural motion and shield it against radiation loss. Using this method, we realize \(f>100\) MHz modes with \(Q\sim 10^4\), consistent with internal loss and contrasting sharply with unshielded beams of similar dimensions. We then study the \(Q\cdot f\) products of high-order modes of mm-long nanobeams. Taking advantage of the mode-shape dependence of stress-induced `loss-dilution', we realize a \(f\approx 4\) MHz mode with \(Q\cdot f\approx9\cdot 10^{12}\) Hz. Our results can extend room temperature quantum coherent operation to ultra-low-mass 1D nanomechanical oscillators.
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