Evaluation of spectral vegetation indices as an indicator of crop coefficient and evapotranspiration under full and deficit irrigation conditions

Two separate field experiments were conducted with sugar beet and green bean, at Ankara, Turkey during the 2005 growing season. Different amounts of irrigation water were applied, and various levels of water stress and vegetation occurred. Spectral reflectance, infrared canopy temperature, and some parameters related to crop evapotranspiration (ET _c) were observed. Daily ET _c values were calculated based on energy balance and soil water balance residual. The fraction of reference ET (ETrF), which is essentially the same with the crop coefficient (K _c), was determined, and relationships between spectral vegetation indices (SVIs) were analysed. Under water stress conditions, the ET _c and ETrF values estimated by means of energy balance were relatively high. In order to improve the correlation between ETrF and SVIs and for correction of ET _c for water‐stressed irrigation treatments, a modification ratio was calculated based on SVIs. Although all three SVIs have a significant relationship with ETrF, the correctness of the modification with a Simple Ratio (SR) was higher. As a consequence, ETrF or crop coefficient (K _c) could be estimated by SR, and this information could be used for irrigation water management of large‐scale agricultural lands.     

Improved mechanical stability of indium zinc tin oxide based flexible transparent electrode through interlayer treatment

Due to the significant growth of the market for numerous flexible electronic devices, demand for mechanically stable indium zinc tin oxide (IZTO) based flexible transparent electrodes has recently expanded substantially. So, we have attempted to increase the mechanical stability of an IZTO based flexible transparent electrode by forming an ultrathin interlayer of an organic semiconductor polystyrene sulfonate doped polyaniline (PANI:PSS). According to the results of the systematic investigation, the PANI:PSS treated IZTO film can preserve 97.50% of its initial average transmittance (AVT) value (83.07%) after 20,000 bending cycles, but the bare IZTO film can retain only 89.00% of its initial AVT value (86.40%) after the same treatment. Furthermore, the PANI:PSS treatment has benefited in the reduction of IZTO film sheet resistance from 17.38 to 16.91 Ω/sq. Scanning electron microscopy images have indicated that the presence of a PANI:PSS interlayer on the IZTO film prevents the formation of fractures on the inorganic IZTO layer when mechanical stress is applied.     

A novel color labeled student modeling approach using e-learning activities for data mining

Universal Access in the Information Society - Student modeling approaches are important to identify students’ needs, learning styles, and to monitor their improvements for individual modules....     

Classification of tea grains based upon image texture feature analysis under different illumination conditions

This paper discusses the role of illumination in discrimination of tea samples based upon textural features of tea granules. The images of tea granules were acquired using 3CCD color camera under Dual Ring light which consists of both Darkfield as well as Brightfield type of illumination. Ten graded tea samples were analyzed. Five textural features were ‘entropy’, ‘contrast’, ‘homogeneity’, ‘correlation’ and ‘energy’ obtained under both illuminations. The acquired textural features were subjected to principal component analysis (PCA). The results showed that best discrimination was obtained with Darkfield illumination with a variance of 96% whereas Brightfield illumination showed low discrimination with only 83% variance. Analysis of PCA biplot indicated correlations among graded tea samples and textural features. The study concludes that textural features may be used to estimate tea quality under Darkfield illumination being non-destructive and quick technique.     

MXene/Fluoropolymer-Derived Laser-Carbonaceous All-Fibrous Nanohybrid Patch for Soft Wearable Bioelectronics

While state-of-the-art skin-adhering fibrous electrodes have distinct benefits in personal wearable bioelectronics, considerable challenges persist in the production of fibrous-based soft conductive biosensing nanomaterials and their integration into efficient multisensing platforms. Here, an electrochemical-electrophysiological multimodal biosensing patch based on MXene/fluoropolymer nanofiber-derived hierarchical porous TiO₂ nanocatalyst interconnected 3D fibrous carbon nanohybrid electrodes is reported. The nanohybrid electrode is produced via a one-step laser carbonaceous thermal oxidation, resulting in excellent elctroconductivity (sheet resistance = 15.6 Ω sq⁻¹), rich active edges for effective electron transmission, and abundant support for enzyme immobilization. The features are attributed to three synergistic effects: i) conductivity of the interior, unoxidized MXene layers, ii) quick heterogeneous electron transmission of the exterior TiO₂ nanoparticles, and iii) the porous disordered carbon's electron “bridge” effects. Based on the foregoing, the nanohybrid modified biosensing patch integrated into textile is demonstrated to be capable of simultaneously and precisely monitoring sweat glucose with pH adjustment (sensitivity of 77.12 µA mm ⁻¹ cm⁻² within physiological concentrations of 0.01–2 × 10⁻³ m ) and electrocardiogram signals (signal-to-noise ratio = 37.63 dB). This novel approach paves the way for controlled investigations of the nanohybrid, for several functionalization and design options, and for the mass manufacturing capabilities required in real-world applications.