.svg)
Recent Submissions
Explore the latest submissions in the repository.
Geospatial analysis of unplanned urbanization: impact on land surface temperature and habitat suitability in Cuttack, India
(Springer Science and Business Media LLC, 2025-02-19)
Unplanned urbanization causes an increase in land surface temperature (LST) and adversely affects the climate and environment within cities. Cuttack City, India, is experiencing rapid urbanization at an alarming rate, facing particular environmental challenges and hosting critical ecosystems that require protection. This study uses the Urban Growth Suitability Index (UGSI) to determine which parts of the city are Suitable and which are unsuitable for habitation based on the geographic distribution of heat vulnerability surrounding Cuttack City from 1990 to 2020. Using a mono window method, the LST for 1990, 2000, 2010, and 2020 is derived from the Landsat 5, Landsat 7, and Landsat 8 satellite data. A simple linear regression model has been used to establish a trend in the relationship between LST and land use/land cover (LULC), similar to UGSI with LST. Finally, the most Suitable and Unsuitable regions for habitation in Cuttack City are marked using UGSI. The findings indicate that the highest temperature in the city was 32.07 °C in 1990 and increased to 38.67 °C in 2020. This is due to the decrease in city vegetation area by 51.39% and the expansion of the urban area by 58.19%. The core region of the city shows higher temperatures than the urban fringes, where vegetation cover is scanty or has no greenery. Out of 59 administrative wards (Municipal administrative regions) in Cuttack City, 27 experienced acute temperatures due to sparse vegetation cover and an intense built environment. A total area of 15.99 km2 of Cuttack City facing this heat vulnerability accounts for 19.61% of the total City area, which is highly unsuitable for habitation, and 10.77 km2 of Cuttack City, which accounts for only 13.21% of the city area are Suitable for habitation. This study will help city planners by guiding actions to protect residents from the adverse effects of extreme heat. By combining thermal and land use analyses with the UGSI framework, this study offers a novel approach to spatially mapping heat vulnerability and urban growth suitability, enhancing urban planning strategies in rapidly urbanizing regions. However, the lack of high-resolution satellite data and the exclusion of socio-economic factors highlight the need for further research. Integrating finer-scale data could offer more robust insights for urban sustainability planning. © The Author(s) 2025.
Unveiling the healing properties of 2,3-dehydrosilychristin: a potential silymarin-derived flavonolignan from Vitex negundo
(Taylor and Francis Ltd., 2025)
The compound 2,3-dehydrosilychristin, a flavonolignan linked to silychristin and silymarin, remains intriguing due to its challenging isolation from silymarin. While silymarin has been the exclusive source of flavonolignans–silybin, silychristin and silydianin − 2,3-dehydrosilychristin is reported in this study from Vitex negundo Linn. leaves. 2,3-Dehydrosilychristin (7) and 14 other compounds were isolated through focused extraction. Its subsequent pharmacological evaluation demonstrated potent antioxidant and in-vitro anti-inflammatory effects, notably inhibiting cytokines TNF-α, IL-6, IL-8 and VEGF. In in-vivo assessments, 2,3-dehydrosilychristin (7) revealed remarkable hepatoprotective potential by reducing liver enzyme levels AST and ALT. These findings expand the potential of 2,3-dehydrosilychristin and suggest bioprospecting Vitex species as alternate sources of bioactive flavonolignans. © 2024 Informa UK Limited, trading as Taylor & Francis Group.
Fabrication of an In2O3 NP-based high-performance low-operating voltage phototransistor and tuning of its photosensitivity from UV to blue region
(Royal Society of Chemistry, 2025)
In this work, a visible-blind low-operating voltage phototransistor was fabricated using colloidal In2O3 nanoparticles (NPs) via a solution process technique, and its photosensitivity was tuned to the blue region by adding a PbI2 layer to the channel. The low-voltage operation of this thin-film transistor (TFT) was achieved by employing an LiInSnO4 gate dielectric with high areal capacitance, which originated from the mobile Li+ ions inside the dielectric thin film. Furthermore, the photosensitivity of the low-voltage TFT was improved through the implementation of an asymmetric source-drain (S-D) electrode of TFT with different work functions, which worked as a driving voltage for photo-generated carriers. Specifically, LiF/Al and MoO3/Ag were used as source and drain electrodes, respectively, which exhibited a work-function difference of ∼−1.16 eV. Incorporating these asymmetric S-D electrodes markedly improved the performance of the In2O3 NP TFT, reducing the subthreshold swing (SS) from 682 to 160 mV per decade, representing a fourfold decrease, and enhancing the on/off current ratio by an order of magnitude. As the band gap of In2O3 NP was ∼3.7 eV, the device was sensitive only towards deep UV region, making it a visible-blind device. The photosensitivity of the device under UV illumination was enhanced by twenty times using the asymmetric S-D electrodes. The photo-response band of this TFT was further tuned to the blue region by adding a PbI2 layer on the In2O3 channel of the TFT. The photosensitivity of the asymmetric electrode-based PbI2/In2O3 heterojunction TFT in the deep UV (∼395 nm) and blue (∼445 nm) regions was 492 and 152, respectively. © 2025 The Royal Society of Chemistry.
Evidence of Spin Reorientation from Γ4 to Γ2 and Sign Reversal Exchange Bias in CeCrO3 Nanoparticles
(John Wiley and Sons Inc, 2025)
Herein, the temperature-dependent magnetic structure and sign reversal exchange bias in CeCrO3 using magnetization data and time-of-flight neutron diffraction data which is given less attention among RCrO3 are investigated. While nuclear structural analysis using Rietveld refinement exhibits distorted orthorhombic structure within Pnma space group, temperature dependence of the magnetic structure using neutron diffraction reveals possible spin configurations, namely, Γ4, Γ2, and Γ1, within the temperature range of 6–300 K. Temperature-dependent magnetization shows compensation temperature, Tcomp, at 58 K, spin reorientation temperature, TSR, at 15 K along with a Neel temperature, TN, at 260 K which is the outcome of the competition between canted antiferromagnetic ordering of Cr3+ ions and Ce3+ ions in CeCrO3. Furthermore, the magnetization versus magnetic field (M vs H) measurements indicate transition of the Γ4 spin structure to Γ2 spin structure around TSR which is further supported by reversible-to-irreversible changes observed in temperature-dependent MFCC and MFCW. Moreover, a temperature-driven sign reversal of exchange bias in CeCrO3 is observed, resulting from the competition between antiferromagnetic coupling between chromium moment (MCr) and cerium moment (MCe) in these nanoparticles. This intriguing behavior holds significant potential for the development of thermally assisted magnetic random access memory. © 2024 Wiley-VCH GmbH.
Optically/electrically controlled Ag+metallization in solution-processed oxide memtransistors for neuromorphic computing
(Royal Society of Chemistry, 2025)
In this work, a solution-processable oxide-based memtransistor is designed for neuromorphic computing, incorporating LiInSnO4as the gate dielectric, SnO2as the semiconducting channel, and Ag+-exchanged LiV3O8as the resistive switching medium. The device demonstrates dual tunability in its channel conductance through both gate voltage and light modulation, enabling precise control over its switching characteristics. Operating at low voltages, the memtransistor achieves an LRS/HRS ratio of up to 103, with stable performance across 103switching cycles, over 106pulse cycles, and retention up to 105seconds. The device effectively replicates essential synaptic functions such as paired-pulse facilitation and short- and long-term plasticity, with ultra-low energy consumption: 193 pJ (0.1 fJ μm−2) optically and 540 pJ (0.3 fJ μm−2) electrically. It also shows low non-linearity in potentiation/depression events, 0.49/3.47 (optical) and 0.03/5.67 (electrical), facilitating accurate synaptic weight modulation. Light-driven logic operations and cognitive functions, learning, forgetting, and relearning are successfully demonstrated, along with Pavlovian classical conditioning. Neural network simulations confirm 98% and 95% recognition accuracy for optical and electrical synapses, while autoencoder-based denoising and data reconstruction further validate the applicability of the device in brain-inspired computing. This journal is © The Royal Society of Chemistry, 2025
Self-biased silicon transistor with a piezoelectric gate for an efficient mechanical energy harvesting device
(Royal Society of Chemistry, 2025)
In this study, a piezo potential gated self-biased transistor was fabricated on a heavily doped silicon (p+-Si) (111) substrate and used for efficient mechanical energy harvesting applications. The drain and source (S-D) electrode of this top gated transistor was made of LiF(5 nm)/Al(65 nm) and MoO3(5 nm)/Ag(65 nm), respectively, whereas piezoelectric poly (vinylidene fluoride-co-hexapropelene) (PVDF-HFP) thin film was used as the gate dielectric. Drain bias (VDS), which was required to transport the hole carrier through the channel, was developed from the work function difference of the S-D electrodes, whereas the piezopotential, which worked as the gate bias of this transistor, was developed from the external force applied on the PVDF-HFP thin film. Consequently, this device efficiently converted mechanical energy into electrical energy. For an applied pressure of 4 bar for ∼5 s, the extracted electrical power per cycle of this device was 1.6 × 10−9 watts with a conversion efficiency of ∼75%, which was an exceptionally high value compared with conventional energy harvesting devices. Besides, the electrical characterization showed its transistor-like behavior, and the extracted device parameters, including threshold force, on-off ratio, and subthreshold swing (SS), were 0.5 N, 4.56 × 102, and 3.16 N A−1, respectively. © 2025 The Royal Society of Chemistry.
Communities in DSpace
Select a community to browse its collections.