The electrochemical oxidation of olive oil mill wastewaters over a titanium-tantalum-platinum-iridium anode was investigated. Batch experiments were conducted in a flow-through electrolytic cell with internal recycle at voltage of 5, 7 and 9 V, NaCl concentrations of 1%, 2% and 4%, recirculation rates of 0.4 and 0.62 L/s and initial chemical oxygen demand (COD) concentrations of 1475, 3060, 5180 and 6545 mg/L. The conversion of total phenols and COD as well as the extent of decolorization generally increased with increasing voltage, salinity and recirculation rate and decreasing initial concentration. In most cases, nearly complete degradation of phenols and decolorization were achieved at short treatment times up to 60 min; this was accompanied by a relatively low COD removal that never exceeded 40% even after prolonged (up to 240 min) times. The consumption of energy per unit mass of COD removed after 120 min of treatment was found to be a strong function of the operating conditions and was generally low at high initial concentrations and/or reduced salinity. The acute toxicity to marine bacteria Vibrio fischeri decreased slightly during the early stages of the reaction and this was attributed to the removal of phenols. However, as the reaction proceeded toxicity increased due to the formation of organochlorinated by-products as confirmed by GC/MS analysis. The toxicity to Daphnia magna increased sharply at short treatment times and remained quite high even after prolonged oxidation. 相似文献
Moderate Resolution Imaging Spectroradiometer (MODIS), land surface temperature data, during daytime (LSTday) or night-time (LSTnight), were employed for predicting maximum (Tmax) or minimum (Tmin) air temperature measured at ground stations, respectively, in order to be used as alternative inputs in minimum data-based reference evapotranspiration (ET) models in 28 stations in Greece during the growing season (May–October). The deviations between daily LSTnight and Tmin were found to be small, but they were greater between LSTday and Tmax. Furthermore, the temperature vegetation index (TVX) method was employed for achieving more accurate Tmax values from LSTday, after determining the normalized difference vegetation index of a full canopy (NDVImax). The TVX method was validated on ‘temporal’ basis, but when the method was tested spatially, the improvement on the Tmax estimates from LSTday was not encouraging, for being used operationally over Greece. Thus, LSTday or LSTnight MODIS data were used as inputs in three ET models [Hargreaves–Samani, Droogers–Allen, and Reference Evapotranspiration Model for Complex Terrains (REMCT)] and their estimations, as compared with ground-based Penman–Monteith estimates, indicated that the REMCT model achieved the most accurate ET predictions (r = 0.93, mean bias error = 0.44 mm day–1 and root mean square error = 0.74 mm day–1), which can allow the spatial analysis of ET at higher spatial resolutions in areas with lack of ground temperature data. 相似文献
Elastic optical networks (EON) have emerged as a solution to the growing needs of the future internet, by allowing for greater flexibility, spectrum efficiency, and scalability, when compared to WDM solutions. EONs achieve those improvements through finer spectrum allocation granularity. However, due to the continuity and contiguity constrains, distant connections that are routed through multiple hops suffer from increased bandwidth blocking probability (BBP), while more direct connections are easier to form. This paper proposes HopWindows, a novel method that strategically allocates bandwidth to connections based on their hop distance. This new algorithm applies masks that control the range of frequency slots (FSs) allocated to each n‐hop connection. Furthermore, a new network metric is introduced, the normalized bandwidth blocking probability (normalized BBP). Utilization of this metric ensures increased fairness to distant connections. Extended simulation results are presented which indicate that the proposed HopWindows method achieves a superior performance over the well‐known FirstFit algorithm. The proposed algorithm may achieve a decrease in bandwidth blocking probability of up to 50%. 相似文献
AbstractBrain processes responsible for the error-related negativity (ERN) evoked response potential (ERP) have historically been studied in highly controlled laboratory experiments through presentation of simple visual stimuli. The present work describes the first time the ERN has been evoked and successfully detected in visual search of complex stimuli. A letter flanker task and a motorcycle conspicuity task were presented to participants during electroencephalographic (EEG) recording. Direct visual inspection and subsequent statistical analysis of the resultant time-locked ERP data clearly indicated that the ERN was detectable in both groups. Further, the ERN pattern did not differ between groups. Such results show that the ERN can be successfully elicited and detected in visual search of complex static images, opening the door to applied neuroergonomic use. Harnessing the brain’s error detection system presents significant opportunities and complex challenges, and implication of such are discussed in the context of human-machine systems.Practitioner Summary: For the first time, error-related negativity (ERN) has been successfully elicited and detected in a visually complex applied search task. Brain-process-based error detection in human-machine systems presents unique challenges, but promises broad neuroergonomic applications. 相似文献
In this paper, the method of tuning the resonant frequency of a micro-resonant clamped–clamped beam has been successfully applied to a MEMS capacitive magnetometer. The resonant structure frequency, which presents the vital component of the sensor, was tuned by applying a bias voltage between the interdigitated capacitive comb-fingers in order to control its spring constant. It has been proved that an applied DC voltage increases the structure stiffness and as a result the resonance frequency to higher values, especially for low motion magnitude. The shifting causes were described through an accurate analytic analysis using the generated electrostatic force between movable and fixed combs, and thereafter have been proved by characterization. The measured resonance frequency of the clamped–clamped beam structure was changed by up to 38 % from the original value (around 18.2 kHz) when a bias voltage of 52 V was applied. Tuning the resonant frequency of the resonating structure has many advantages for the magnetometer since it can serve as a feedback mechanism for error compensation.
The effects of Ni(II) and Co(II) on the activated sludge growth rate have been assessed for a batch growth system, for a range of concentrations between 0 and 320 mg L(-1). The activated sludge was not acclimatized to the above metallic species, while a synthetic rich growth medium was used as substrate throughout out the experimental trials. Ni(II) and Co(II) have been found to stimulate microbial growth at concentrations approximately below 27 and 19 mg L(-1), with maximum stimulation concentrations 10 and 5 mg L(-1), respectively. The lethal concentrations (zero growth) for both species have been found to lie between 160 and 320 mg L(-1), with Co(II) identified as more potent growth inhibitor compared to Ni(II). The behaviour of activated sludge was also tested at the presence of three Ni(II) and Co(II) quotas, at various concentrations (75%Ni-25%Co (w/w), 50%Ni-50%Co (w/w) and 25%Ni-75%Co (w/w)). All the mixtures stimulated more drastically the activated sludge growth at relatively small concentrations, compared with the stimulation of equal concentrations of single species, whilst they also acted as more potent inhibitors at relatively high concentrations. Based on the isobole method, the data indicated that Ni(II) and Co(II) acted synergistically at the increasing stimulation and at the intoxication zones, whilst an antagonistic relation determined at the decreasing stimulation zone. Under the light of the present study, it is obvious that interactions (particularly synergism) between different metallic species should be taken into account in the methodologies used to establish criteria for tolerance levels in the environment. 相似文献
In areas lacking substantial freshwater resources, the utilisation of alternative water sources, such as desalinated seawater and reclaimed water, is a sustainable alternative option. This paper presents an optimisation approach for the integrated management of water resources, including desalinated seawater, wastewater and reclaimed water, for insular water deficient areas. The proposed mixed integer linear programming (MILP) model takes into account the subdivided regions on the island, the subsequent localised needs for water use (including water quality) and wastewater production, as well as geographical aspects. In addition, the integration of potable and non-potable water systems is considered. The optimal water management decisions, including the location of desalination, wastewater treatment, and reclamation plants, as well as the conveyance infrastructure for desalinated water, wastewater and reclaimed water, are obtained by minimising the annualised total capital and operating costs. Finally, the proposed approach is applied to two Greek islands: Syros and Paros-Antiparos, for case study and scenario analysis. 相似文献
To evaluate simultaneous multislice (sms) accelerated diffusion-weighted imaging (DWI) of the liver in comparison to conventional sequences.
Materials and methods
Ten volunteers underwent DWI of the liver at 1.5 T. Four different sms-accelerated sequences with monopolar and bipolar gradient preparation (MP, BP) and acceleration factors 2 and 3 (sms2-DWI, sms3-DWI) were compared to conventional DWI (c-DWI). Image quality criteria rated on a 5-point Likert scale (5 = excellent), image quality sum scores (maximum 120), and ADC were compared using Friedman test and Dunn-Bonferroni post hoc test. Bland–Altman plots were calculated for ADC comparison. p values <0.05 were considered significant.
Results
Sms2-DWI offered scan time minimization of 67 % without significant difference in image quality (sum score: sms2-DWI MP/BP: 97 ± 8/92 ± 9; c-DWI MP/BP: 99 ± 8/97 ± 8). Sms3-DWI offered slight additional scan time minimization with significantly inferior image quality (sum score: sms3-DWI MP/BP: 75 ± 14/69 ± 14; p < 0.001). MP preparation provided slightly higher image quality in sms-DWI without statistical significance. ADC in sms-DWI were significantly lower (sms2-DWI MP 1.01 × 10?3 mm2/s; c-DWI MP 1.20 × 10?3 mm2/s; p < 0.001).
Conclusion
Sms2-DWI provides considerable scan time minimization without significant shortcomings in image quality. Sms3-DWI provides significantly inferior image quality without further scan time minimization. Potentially lower ADC in sms-DWI should be considered in clinical routine.
The objective of the study was to establish a validated kinetic model for growth of spoilage bacteria on vacuum packed tuna slices in the temperature range of 0 to 15 degrees C and to evaluate the applicability of the TTI (Time Temperature Integrators) based SMAS (Safety Monitoring and Assurance System) system to improve tuna product quality at the time of consumption in comparison to the conventional First In First Out (FIFO) approach. The overall measurements of total flora and lactic acid bacteria (LAB) on the tuna samples used in a laboratory simulated field test were in close agreement with the predictions of the developed kinetic model. The spoilage profile of the TTI bearing products, handled with SMAS, was improved. Three out of the thirty products that were handled randomly, according to the FIFO approach, were already spoiled at the time of consumption (logN(LAB)>6.5) compared to no spoiled products when handled with the SMAS approach. 相似文献