Detection and spatial analysis of selective logging with geometrically corrected Landsat images

The Brazilian Amazonian rain forests are under imminent threat of serious degradation and ultimately deforestation. Human activities such as selective logging are an important cause. Selectively logged locations are difficult to detect from medium-resolution Landsat images, due to their relatively small sizes and subtle spatial patterns. Spectral linear unmixing provides an effective tool for the purpose. The orientation of geometrically corrected images, however, artificially introduces zero-reflectance background pixels. These change the variance–covariance structure of the image bands and hinder the identification of pure endmembers. In this study, we compare image cropping and image rotation as two alternative approaches. Selectively logged forests were detected in northern Rondônia state, north-western Mato Grosso state and south-eastern Amazonas state in Brazil by applying spectral unmixing. The study shows that image rotation is a better approach as it preserves the image extent and thus provides information on forest degradation over a wider region. Spatial statistical analysis of the detected locations shows strong clustering within the study area. We conclude that the endmembers used in this study represent basic components of a degraded forest environment. As spectral unmixing of remote-sensing images avoids collection of field data, it may broadly be applied towards other Amazonian regions as well.     

Modular multi-level converter-based DFIG wind power system with MMC-STATCOM

ABSTRACT

Transmission and distribution conversion operation, voltage, current magnitude variation and time-to-time power flow change through grid are the major issues in power system. Variable wind energy system is more popular for power generation through conventional converters and hence harmonic reduction is very less in these converters. In this paper, 9?MW modular multi-level converter-based DFIG wind energy power system parameters are compared with 9?MW DFIG systems using conventional converter. DFIG is operated in four mode condition with proper back-to-back power electronic converters and controllers. In power electronics, the modular multi-level converters are more advanced for reducing transients, peak response oscillations and improving the efficiency of the system. A five-level MMC has been applied in back-to-back converter with phase disposition (PD) PWM technique for DFIG wind system of the same rotor side controller and grid side controller. A conventional converter-based DFIG wind energy system is replaced with five-level MMC-based system with level shift PD-PWM technique. The impact of MMC on DFIG wind energy system is reduced voltage and current harmonics fast settling time compared to conventional converter-based DFIG system. The above MMC DFIG power system voltage is balanced at fault condition with MMC-STATCOM.     

Influence of hydrogen and carbon monoxide on reduction behavior of iron oxide at high temperature: Effect on reduction gas concentrations

The purposes of this study are to reduce Fe₂O₃ using hydrogen (H₂) and carbon monoxide (CO) gases at a high temperature zone (500 °C–900 °C) by focusing on the influence of reduction gas concentrations. Reduction behavior of hematite (Fe₂O₃) at high temperature was examined using temperature programmed reduction (TPR) under non-isothermal conditions with the presence of 10% H₂/N₂, 20% H₂/N₂, 10% CO/N₂, 20% CO/N₂ and 40% CO/N₂. The TPR_CO results indicated that the first and second reduction peaks of Fe₂O₃ at a temperature below 660 °C appeared rapidly when compared to TPR_H2. However, TPR_H2 exhibited a better reduction in which Fe₂O₃ entirely reduced to Fe at temperature 800 °C (20% H₂) without any remaining of wustite (FeO) whereas a temperature above 900 °C is needed for a complete reduction in 10% H₂/N₂, 10% and 20% CO/N₂. Furthermore, the reduction of hematite could be improved when increasing CO and H₂ concentrations since reduction profiles were shifted to a lower temperature. Thermodynamic calculation has shown that enthalpy change of reaction (ΔHr) for all phases transformation in CO atmosphere is significantly lower than in H₂. This disclosed that CO is the best reductant as it is a more exothermic, more spontaneous reaction and able to initiate the reduction at a much lower temperature than H₂ atmosphere. Nevertheless, the reduction of hematite using CO completed at a temperature slightly higher compared to H₂. It is due to the presence of an additional carburization reaction which is a phase transformation of wustite to iron carbide (FeO → Fe₃C). Carburization started at the end of the second stage reduction at 600 °C and 630 °C under 20% and 40% CO, respectively. Therefore, reduction by CO encouraged the formation of carbide, slower the reduction and completed at high temperature. XRD analysis disclosed the formation of austenite during the final stage of a reduction under further exposure with high CO concentration. Overall, less energy consumption needed during the first and second stages of reduction by CO, the formation of iron carbide and austenite were enhanced with the presence of higher CO concentration. Meanwhile, H₂ has stimulated the formation of pure metallic iron (Fe), completed the reduction faster, considered as the strongest reducing agent than CO and these are effective at a higher temperature. Proposed iron phase transformation under different reducing agent concentrations are as followed: (a) 10% H₂, 20% H₂ and 10% C; Fe₂O₃ → Fe₃O₄ → FeO → Fe, (b) 20% CO; Fe₂O₃ → Fe₃O₄ → FeO → Fe₃C → Fe and (c) 40% CO; Fe₂O₃ → Fe₃O₄ → FeO → Fe₃C → Fe → F,C (austenite).     

Optimizing electrochemical performance of sonochemically and hydrothermally synthesized cobalt phosphate for supercapattery devices

The supercapattery (hybrid energy storage device) has procured miraculous heed for their significant electrochemical performance, constitute combine features of supercapacitor (prodigious power density) and batteries (substantial energy density), still crave for electrode material with better electrochemical conduct. Here, cobalt phosphate ((Co₃(PO₄)₂) nanostructures were synthesized using sonochemical and hydrothermal approach. The SEM, XRD, and EDX were employed to explore surface morphology, crystal structure, and elemental analysis respectively of as synthesized nanomaterials. The electrochemical performance was evaluated in two and three electrode assembly. The maximum specific capacity of 285 C g^-1 at 3 mV/s and 221 C g^-1 at 4.1 A g^-1 has been obtained by sonochemically synthesized nanomaterial (S1). This electrode material with optimum electrochemical performance was further investigated for supercapattery application. Asymmetric device was fabricated, comprising activated carbon as negative and S1 as positive electrode material. The supercapattery device exhibits a specific capacity of 147.2 C g^-1 bearing an outstanding energy density of 34.8 Whkg^?1 with a power density of 425.0 W kg^-1 at 0.5 A g^-1. The device was found to have a remarkable power density of 6800.0 W kg^-1 while retaining an energy density of 10.0 Whkg^?1 with exceptional capacity preservation of 87.2% after 10,000 consecutive GCD cycles even at 8.0 A g^-1. The device performance was further explored in terms of capacitive and diffusion controlled processes and found to have a maximum capacitive contribution of 63.8% at 100 mV s^-1. The sonochemical method was found to be the optimal route to synthesize nanomaterials for energy storage applications.     

Radio interference challenges in a multiprotocol compact RF hardware platform for home and building automation applications

In the field of smart home and smart building, there is a wide range of products using various proprietary and open standards for their interconnection. However, the coexistence of those standards imposes serious constraints because of the inherent nature of the radio frequency propagation. A way to investigate this issue is to study the interferences in a compact hardware platform/box in which several radio transceivers work side by side, potentially causing interference and radio link degradation due to antennas coupling. To achieve this analysis and predict the radio issues, a simulation tool was developed, and several experimental tests were conducted indoors and outdoors to validate the simulation model. The compact platform investigated consists of multiprofile KNX‐RF modules for home automation and smart grid control, and a radio alarm module for security needs. Simulations were conducted using MATLAB/Simulink, which are based on a calculation of bit error rate according to the signal to noise ratio in order to deduce the radio coverage range in different interference scenarios. The simulation tool developed was optimized to match the behavior of a specific transceiver commonly used for KNX‐RF devices. Yet the tool can be adapted to simulate other kinds of transceivers. Furthermore, the methodology applied to evaluate the cross‐technology interference can be extended to other technologies like Wi‐Fi, ZigBee, and EnOcean.     

Physicochemical,Phytochemical and Mycological Characteristics of Italia Muscat Raisins Obtained Using Different Pre-treatments and Drying Techniques

Raisins represent an economically important grapevine by-product. However, their quality is largely dependent on drying techniques and processing conditions. In this context, two drying processes were monitored: hot air drying in a convective oven and greenhouse drying. Grape berries were previously subjected to two chemical pre-treatments (olive oil and K₂CO₃ emulsion dipping (I) and NaOH solution bleaching (II)). Pre-treated grapes processed using both methods were compared with sun-dried samples. The results show that oven drying was more efficient and rapid (5 days) as compared with greenhouse drying (13 days). The end moisture content of grapes varied from 16.12% to 22.25% on a wet basis in dried samples, respectively. Significant differences in the pH value (3.85–4), acidity (1172.5–2730 mg TA/100 g DW) and total sugars (31.5–49.7%) were also observed, between raisin samples subjected to both treatments and drying methods, whereas protein levels (1–1.25%) were not affected. The analysis of minerals indicates that greenhouse-dried raisins had high amounts of calcium (Ca), magnesium (Mg) and sodium (Na). The highest polyphenol (417.70 mg GAE/100 g DW), flavonoid (115.87 mg CE/100 g DW) and tannin (368.13 mg CE/100 g DW) contents were recorded in sun-dried samples, respectively. The distribution of fungal flora shows a noteworthy variability among raisin samples, with a marked abundance of ochratoxinogenic species such as Aspergillus ochraceus and Aspergillus carbonarius (15.56% and 10.41%, respectively). Italia Muscat raisins processed using oven drying could be an economically interesting alternative to manage the excessive grapes production and consequently solve related marketing issues.     

EQOWSN: Evolutionary-based query optimization over self-organized wireless sensor networks

In this paper, a new approach has been introduced that integrates an evolutionary-based mechanism with a distributed query sensor cover algorithm for optimal query execution in self-organized wireless sensor networks (WSN). An algorithm based on an evolutionary technique is proposed, with problem-specific genetic operators to improve computing efficiency. Redundancy within a sensor network can be exploited to reduce the communication cost incurred in execution of spatial queries. Any reduction in communication cost would result in an efficient use of battery energy, which is very limited in sensors. Our objective is to self-organize the network, in response to a query, into a topology that involves an optimal subset of sensors that is sufficient to process the query subject to connectivity, coverage, energy consumption, cover size and communication overhead constraints. Query processing must incorporate energy awareness into the system by reducing the total energy consumption and hence increasing the lifetime of the sensor cover, which is beneficial for large long running queries. Experiments have been carried out on networks with different sensors Transmission radius, different query sizes, and different network configurations. Through extensive simulations, we have shown that our designed technique result in substantial energy savings in a sensor network. Compared with other techniques, the results demonstrated a significant improvement of the proposed technique in terms of energy-efficient query cover with lower communication cost and lower size.     

Automatic detection and severity classification of diabetic retinopathy

Multimedia Tools and Applications - Diabetic retinopathy (DR) is a leading cause of preventable blindness caused by damaged blood vessels in the eye, if not treated early on. The aim of this...     

HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY DETERMINATION OF ANILINES WITH FLUORESCENT DETECTION AND PRE-COLUMN DERIVATIZATION

A simple, sensitive, and rapid reverse-phase high-performance liquid chromatography (RP-HPLC) method for the determination of anilines in water is proposed. The use of 2,7-diethylamino-2-oxo-2H-chromen-3-yl-benzothiazole-6-sulfonylchloride (coumarin 6-SO₂Cl) as a fluorigenic-labeling reagent was investigated. The label reacted with aniline within 30 min under mild conditions (ambient temperature, pH 9.0) to give sulfonamides that were separated by RP-HPLC employing fluorescence detection with an excitation wavelength of 470 nm and an emission wavelength of 520 nm. The optimum conditions for fluorescence, derivatization, and chromatographic separation were established. The calibration curves were linear for the range 0–800 ppb. The proposed method was applied for the determination of anilines in spiked drinking water samples and irrigation water samples with recoveries of 90.0–103.9% and relative standard deviations of 1.2–4.7%, respectively. This method showed good accuracy and repeatability that can be used for the quantification of aniline in real samples.