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Comfortable indoor lighting conditions for LEDlights evaluated from psychological and physiological responses
摘要： Comfortable light emitting diode (LED) lighting conditions were examined for psychological and physiological responses. Eight male and eight female subjects participated in a series of experiments. They were exposed to light emitted from LED lights of 3000 K in the ranges of 150–400 lux and 1500–5000 lux; 4000 K in the ranges of 140–640 lux and 2000–5000 lux; and 5000 K in the ranges of 70–270 lux and 2500–7000 lux. Illuminance at a given correlated color temperature was first maintained at the lowest value in the designated range and then increased in a stepwise manner. On reaching the highest value in the range, it was then decreased to the lowest value in a stepwise manner. The subjects were required to indicate their perception of brightness, glare, and comfort at the controlled illuminance levels. Electrocardiogram and electroencephalogram data were monitored continuously throughout exposure. The results showed that the boundary illuminances estimated from psychological and physiological responses did not significantly differ between male and female subjects, but differed markedly from those of fluorescent lights tested in a previous study. The high boundaries of the LED lights were higher than those of the fluorescent lights. The low boundaries of the LED lights at 3000 K and 4000 K were higher than those of the fluorescent lights, but the boundaries at 5000 K were lower than those of the fluorescent lights. These differences may be due to differences in the spectral distribution and luminance for a given illuminance between LED and fluorescent lights.
关键词： Electroencephalogram,Heart rate variability,Light intensity,Correlated color temperature
更新于2025-09-12 10:27:22
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Quantifying variabilities and impacts of massive photovoltaic integration in public power systems with PHS based on real measured data of Kyushu, Japan
摘要： Increasing renewable penetration will profoundly affect the grid balance scenario, such as thermal generator flexibility, storage utilization and renewable market value. This paper explores the variabilities and impacts of massive PV integrated into grid with hydro pump balance dispatch, based on real chronological order data of Kyushu. The PV feed-in and storage dispatch conditions are described and compared among seasons, PV integration can greatly shape the net grid load, analysis shows that pump solar energy will increase when its generation excesses around 35.0% ratio of residual load (subtracting nuclear constant output). Hydro pump storage effectively absorbs the excess solar production and maintains the grid flexibility. Further increasing integrated PV capacity will lead necessary output suppression due to limitation of grid flexibility and pump storage ability, the utilization frequency of storage system will be enhanced. When the PV penetration increases from 8.15% to 12.0%, the effective PV utilization per capacity will drop (8.0%) due to the pump cycle loss and output curtailment. The proposed approach and analysis result could extended and provide references for similar utilities with variable renewable energy expansion plan.
关键词： Hydro pump storage,PV,Variability,Grid load
更新于2025-09-12 10:27:22
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Characterization of temporal variations and feedback timescales of exhaust gas recirculation gas properties using high-speed diode laser absorption spectroscopy for next-cycle control of cyclic variability
摘要： Dilute combustion offers efficiency gains in boosted gasoline direct injection engines both through knock-limit extension and thermodynamic advantages (i.e. the effect of g on cycle efficiency), but is limited by cyclic variability at high dilution levels. Past studies have shown that the cycle-to-cycle dynamics are a combination of deterministic and stochastic effects. The deterministic causes of cyclic variations, which arise from feedback due to exhaust gas recirculation, imply the possibility of using active control strategies for dilution limit extension. While internal exhaust gas recirculation will largely provide a next-cycle effect (short-timescale feedback), the feedback of external exhaust gas recirculation will have an effect after a delay of several cycles (long timescale). Therefore, control strategies aiming to improve engine stability at dilution limit may have to account for both short- and long-timescale feedback pathways. This study shows the results of a study examining the extent to which variations in exhaust gas recirculation composition are preserved along the exhaust gas recirculation flow path and thus the relative importance and information content of the long-timescale feedback pathway. To characterize the filtering or retention of cycle-resolved feedback information, high-speed (1–5 kHz) CO2 concentration measurements were performed simultaneously at three different locations along the low-pressure external exhaust gas recirculation loop of a four-cylinder General Motors gasoline direct injection engine using a multiplexed two-color diode laser absorption spectroscopy sensor system during steady-state and transient engine operation at various exhaust gas recirculation levels. It was determined that cycle-resolved feedback propagates through internal residual gases but is filtered out by the low-pressure exhaust gas recirculation flow system and do not reach the intake manifold. Intermediate variations driven by flow rate and compositional changes are also distinguished and identified.
关键词： exhaust gas recirculation,cyclic variability,nonlinear dynamics,combustion stability,Dilute combustion
更新于2025-09-12 10:27:22
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Experimental Investigations To Optimize Process Parameters For CO2 Laser Welded Alloy Steel Automotive Gears
摘要： In the present research, CO2 laser welding process is successfully applied and optimized for joining automotive gears of 16MnCr5 Alloy Steel. The combinations of laser power and speed of welding are optimized with the aim to produce welded joint in automotive gear-synchro assembly with required weld depth, weld width and weld strength. Taguchi method of “Design of Experiments (DOE)” and ANOVA have been used as statistical design tools and techniques for optimizing the selected welding process parameters. Further, variation transmission analysis technique has also been applied to determine the range of input variable that gives least variability of the output. The result of this research effort indicates that the developed models are capable of predicting the responses with negligible errors.
关键词： ANOVA,Taguchi Method,Alloy Steel 16MnCr5,Variability Transmission,DOE,CO2 LASER
更新于2025-09-12 10:27:22
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Understanding the laser-induced aerosol ablation of sub-micron liquid particles <i>via</i> size-resolved spectral and image analyses
摘要： Laser-induced breakdown spectroscopy of aerosols is associated with large signal variability and lower sampling rates. In this study, aerosol ablation and signal variability associated with aerosol size were studied by size-resolved spectral and image analyses of submicron sized particles using a high-density stream of monodisperse liquid aerosols. The rise in the particle size from 0.16 mm to 0.96 mm for a similar aerosol mass concentration showed a size-dependent intensity increase. The initial increase in the analyte emission was due to the enhanced analyte concentration inside the plasma volume, whereas for larger aerosols, the stronger ablation of the larger liquid particles resulted in elevated emission intensity. The electron number density increased from 1.6 (cid:1) 1017 cm(cid:3)3 to 2.6 (cid:1) 1017 cm(cid:3)3 with an increase in the particle size; however, the temporal delay of number density was faster for the larger particles due to higher plasma–ambience interaction. The analyte signal variation reduced to 3%, calculated using ensemble averaging, for particles larger than 0.5 mm. Plasma image analysis showed that the signal variation stemmed from inhomogeneity in the initial breakdown process and grew with the increasing delay. The variation in the plasma image area increased from 8% to 16% for 0.16 mm particles and 12% to 28% for 0.96 mm particles at the respective delays of 0 and 3 ms. Thus, two di?erent sources of signal variability were determined. For smaller particles, the major source of variation was the variable sample scarcity inside the plasma, whereas for larger particles, plasma variation contributed more to the analyte signal variability from the beginning.
关键词： Laser-induced breakdown spectroscopy,plasma,submicron particles,aerosols,signal variability
更新于2025-09-12 10:27:22
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Dot size variability induced changes in the optical absorption spectra of interdiffused quantum dot systems
摘要： In this work, we have quantified the effects of dot size variability on the interband optical absorption spectra of interdiffused III–V quantum dot (QD) systems through analytical models which agree well with experimental data. The variability function induced due to inhomogeneous nature of dot size distribution has been considered to be Gaussian in nature, where individual dots have been assumed to be lens-shaped having inhomogeneous material composition inside the dot. This is necessary to consider any realistic interdiffused system. Such an assumption is not in line-up with the conventional methodologies reported earlier on the subject, where the QD composition was considered to be homogeneous, presenting an ideal or quasi-ideal situation which may be applicable only for dot structures in absence of interdiffusion. Moreover, for the first time, the effects of dot size variability and interdiffusion on the optical spectra of QD systems have been analysed in the same platform. The effects of dot size deviation, QD aspect ratio, core group III content inside the dot, standard deviation, and so on, on the optical absorption spectra have been demonstrated.
关键词： Dot size variability,III–V semiconductors,Optical absorption spectra,Interdiffusion,Quantum dots
更新于2025-09-11 14:15:04
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Resistive Switching and Charge Transport in Laser-Fabricated Graphene Oxide Memristors: A Time Series and Quantum Point Contact Modeling Approach
摘要： This work investigates the sources of resistive switching (RS) in recently reported laser-fabricated graphene oxide memristors by means of two numerical analysis tools linked to the Time Series Statistical Analysis and the use of the Quantum Point Contact Conduction model. The application of both numerical procedures points to the existence of a filament connecting the electrodes that may be interrupted at a precise point within the conductive path, resulting in resistive switching phenomena. These results support the existing model attributing the memristance of laser-fabricated graphene oxide memristors to the modification of a conductive path stoichiometry inside the graphene oxide.
关键词： graphene oxide,memristor,autocovariance,RRAM,variability,laser,time series modeling
更新于2025-09-11 14:15:04
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Influence of Quantum Dot Characteristics on the Performance of Hybrid SET-FET Circuits
摘要： Quantum dots (QDs) can be used as conductive islands to build-up single-electron transistors (SETs). The characteristics of the QDs define the functional performance of the SETs. In consequence, analyzing the influence of the variations of QD dimensions on the performance of hybrid SET-FET circuits is of high relevance. We employ a self-developed SET compact model which is calibrated to 3-D quantum-mechanics-based simulations in order to obtain realistic model parameters. A method to improve the circuit behavior, i.e., to increase the output current, is proposed. It is concluded that the variation of the QD size presents the largest influence on the overall circuit behavior.
关键词： variability,single-electron transistor (SET),quantum dot (QD),Nanowires
更新于2025-09-11 14:15:04
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Spectral data source effect on crop state estimation by vegetation indices
摘要： Spectral vegetation indices (VIs) are a well-known and widely used method for crop state estimation. The ability to monitor crop state by such indices is an important tool for agricultural management. Even though differences in imagery and point-based spectroscopy are obvious, their impact on crop state estimation by VIs is not well-studied. The aim of this study was to assess the performance level of the selected VIs calculated from spaceborne multispectral imagery and point-based field spectroscopy in application to crop state estimation. For this purpose, irrigated chickpea field was monitored by RapidEye satellite mission and additional measurements by field spectrometer were obtained. Estimated VIs average and coefficient of variation from each observation were compared with physical crop measurements: leaf water content, LAI and chlorophyll level. The results indicate that indices calculated from spaceborne spectral images regardless of the claimed response commonly react on phenology of the irrigated chickpea. This feature makes spaceborne spectral imagery an appropriate data source for monitoring crop development, crop water needs and yield prediction. VIs calculated from field spectrometer were sensitive for estimating pigment concentration and photosynthesis rate. Yet, a hypersensitivity of field spectral measures might lead to a very high variability (up to 69%) of the calculated values. Consequently, the high spatial variability of field spectral measurements depreciates the estimation agricultural field state by average mean only. Nevertheless, the spatial variability might have certain behavior trend, e.g., a significant increase in the active growth or stress and can be an independent feature for field state assessment.
关键词： Vegetation indices,Spatial variability,Agriculture management,Field spectroscopy,Spaceborne spectral imagery
更新于2025-09-11 14:15:04
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Computational Assessment of Silicon Quantum Gate Based on Detuning Mechanism for Quantum Computing
摘要： Silicon-based quantum computing has the potential advantages of low cost, high integration density, and compatibility with CMOS technologies. The detuning mechanism has been used to experimentally achieve silicon two-qubit quantum gates and programmable quantum processors. In this paper, the scaling behaviors and variability issues are explored by numerical device simulations of a model silicon quantum gate based on the detuning mechanism. The device physics of quantum gates modulation, tradeoff between device speed and quantum fidelity, and impact of variability on the implementation of a quantum algorithm are examined. The results indicate the attractive potential to achieve high speed and fidelity silicon quantum gates with a low operation voltage. To scale up, reducing the device variability and mitigating the variability effect are identified to be indispensable for reliable implementing a quantum computing algorithm with the silicon quantum gates based on the detuning mechanism. A scheme to use the control electronics for mitigating the variability of quantum gates is proposed.
关键词： variability,quantum gate,Detuning,device modeling
更新于2025-09-11 14:15:04