In recent years, the dynamism of landscapes has drawn attention to scientific investigation, with geomorphological, sedimentological, hydrogeological, and erosion-based analyses conducted on a global scale. This study examines the geomorphological evolution of the Satluj Valley, Northwestern Himalaya, employing morphometric parameters comprising the stream length gradient index (SL-Index), steepness index (Ksn), hypsometric analysis, valley-floor width-to-height ratio (Vf), and Chi analysis (chi), knickpoint analysis and field investigations. Results reveal significantly elevated SL-Index and Ksn values (> 2000) in conjunction with low Vf ratios (< 1) near prominent tectonic discontinuities, that is, the Main Boundary Thrust (MBT), Main Central Thrust (MCT) and South Tibetan Detachment System (STDs). Basin hypsometry suggests a youth to mature stage, reflecting tectonic and erosional control on sediment mobility and valley evolution. Dynamic tectonics and landscape instability in the Satluj Valley are indicated by geomorphic features such as dammed-lake deposits, river ponding, deep gorges, high relief, fault scarps and widespread landslides. Terrestrial data link denudation rates, exhumation ages, and channel steepness along structural discontinuities to comprehend landscape evolution. The present findings highlight the evolving regional landscape and enhanced tectonic disturbances affecting the drainage network of the Satluj River basin. Widespread landslides on the valley's steep slopes trigger drainage migration and sediment movement, which form hanging paleolake topography, deep gorges, strath terraces, and kilometre-scale debris fans. The enhanced erosion rates generate complex multi-hazard conditions in the valley. The geomorphological framework of the Satluj Valley emphasises that the coupling of tectonic activity and climatic forces is responsible in shaping the valley's topography.

The progradation of the deltaic sequences within the Pangong Lake (Bangong Co), Ladakh Himalaya, has been studied using sedimentological, geomorphological, optically stimulated luminescence (OSL) chronology and geophysical investigations. This study advances the understanding of lake-delta processes in high-altitude arid regions by documenting how deltaic systems in small basins encode millennial to sub-millennial scale hydro-climate variability. The deltaic evolution of Pangong Tso reflects temporal variations in accommodation and fluvial sediment supply, consistent with independently inferred lake-level fluctuations. Five facies associations (FA) representing bottomset, foreset, topset, beach, and distributary channel environments are identified, defining a typical Gilbert-type delta architecture. Spatio-temporal correlation among these facies indicates that deltaic depocenters migrated in response to changes in accommodation space, expressed through shifts in shoreline position. The phases of relatively reduced accommodation are consistent with relatively lower lake levels in the late Pleistocene–early Holocene. During these phases, the subaerial exposure of the basin margins promoted fluvial incision and delta progradation. Subsequent increases in accommodation, possibly associated with relatively higher lake levels during the mid-Holocene, led to aggradational to retrogradational stacking and the development of delta-front deposits. Episodes of lake-level fall were associated with the reactivation of distributary channels and renewed progradation. The lake level has declined rapidly since 1.1 ka, resulting in an abrupt shift in sediment accommodation space lakeward. Overall, the Pangong Tso system demonstrates strong source-to-sink connectivity, where sediment supply and accommodation space respond rapidly to hydroclimatic forcing with minimal temporal lag. Our findings contribute to broader models of delta evolution and stratigraphic response in closed-basin settings and provide insights into the interaction between hydroclimatic variability, accommodation space, and sediment supply in short-routing fluvial systems.

The Himalaya and its foreland, a thrust fold belt, is one of the most geomorphically dynamic and populous regions on Earth. The tectonic forces and climate driven surface processes persistently shape the landscape of the region. The river systems draining through this mountain range actively respond to neotectonic deformation and climatic changes, recording the long-term history of mountain building and erosion. In this paper, we review the chronologically constrained fluvial archives such as river fills, strath terraces, and alluvial fans from the Indus, Ganga, Gandaki, and Brahmaputra systems. Together, these rivers capture the full range of climatic and tectonic conditions across the Himalaya. Building on these studies, we propose an integrated view of how climate and tectonics have jointly influenced the region's landscape evolution. Aggradation and incision in these rivers are controlled by the balance between sediment supply and stream power, which are linked to the changes in monsoon intensity and tectonic uplift. Chronological data reveal three main aggradational phases in the Indus (49-39, 30-20, and 13-5 ka) and Ganga (46-36, 29-23, and 16-8 ka), and two in the eastern Himalaya (32-22, and 18-8 ka), corresponding to glacial-interglacial transitions. Periods of climatic recovery from cold-dry to warm-humid conditions favored valley filling and fan formation, while strong monsoon phases triggered river incision and terrace development. Extreme monsoon-driven floods during 39-31ka and 13-5 ka left widespread sedimentary imprints across the mountain belt. Fluvial archives across the Himalaya-Ganga Plain system shows a time-lagged response of 3-4 ka between incision in the mountains and in the foreland. The pattern reflects tight coupling between tectonic deformation and climate-driven erosion. Neotectonic deformation in the NW Himalaya is expressed through active nature of south-vergent frontal thrusts and north-vergent backthrusts, forming a bivergent wedge. Rivers in this region record deformation in the form of strath terraces, which reflect alternating phases of uplift, incision, and stability, with incision rates ranging from similar to 1 to 15 mm/yr with highest rates near the Himalayan Frontal Thrust. Spatial variations in the bedrock uplift and erosion reveal strong tectono-geomorphic coupling-rapid deformation at the frontal wedge, out-of-sequence uplift in the Lesser Himalaya, and active extensional faulting in the Tethyan sector. Together, these features demonstrate that the Himalaya is a critically tapered, asymmetric bivergent wedge, where both frontal thrusting and hinterland faulting actively shape uplift, erosion, and landscape evolution. The Ganga foreland basin also remains tectonically active, influenced by Himalayan thrusting, reactivated basement faults, and flexural movements along the peripheral bulge. These forces have shaped its river systems, sedimentation, and characteristic landforms such as ravines, unconformities, and uplifted surfaces. Together, these insights highlight how deeply intertwined tectonics and climate are in sculpting the dynamic Himalayan landscape.

Weathering is a key exogenic process that supplies sediments to rivers and drives global biogeochemical cycles. This study quantifies the impact of water availability on rock weathering using U-series isotopes from two granite weathering profiles in the climatically distinct Himalayan regions: the humid Lesser Himalaya and the semi-arid Higher Himalaya. The humid conditions in the Lesser Himalaya have accelerated weathering rates by up to 3.5 times compared to the semi-arid Higher Himalaya, with at least a twofold increase in element flux. The similar to 60 ka weathering record in the Higher Himalaya corresponds to the deglaciation period, and due to low residence time, the profile here is thinner and weathering intensity is less than that of the Lesser Himalayan weathering profile. The metagenomics-based study on the Lesser Himalayan weathering profile provides further insights into biogenic mediation in weathering. Microbes disintegrate primary minerals in fresh rock to utilize mineral-bound nutrients and reprecipitate secondary carbonate in the soil. In contrast, in the nutrient-depleted, highly weathered zone, microbes rely on carbon sources, produce organic acids, and disintegrate K-feldspar to release potassium for plant uptake. Additionally, they capture soil CO2 and convert it into bicarbonates, highlighting the importance of quantifying biological carbon capture. The datasets produced in this study represent granite weathering fluxes across the climate gradient in the Himalaya. Further, by providing the first in-situ U-series-based weathering timescales, the research bridges a critical gap in understanding weathering dynamics in one of the world's most tectonically active mountain belts.

Understanding sediment provenance is crucial for reconstructing past environmental conditions and deciphering erosion patterns in rapidly evolving mountain belts such as the Himalaya. The Yarlung–Tsangpo–Brahmaputra system, one of the world’s most dynamic sediment-routing networks, provides a key setting to examine how extreme hydrological events mobilize material from distinct source terranes. In this study, we analyse five well-dated paleoflood deposits from the Siang River using an integrated suite of provenance tools—sand petrography, U–Pb zircon geochronology, and Sr–Nd isotope geochemistry—to evaluate their relative strengths and interpretive limitations.Petrographic data show quartz–feldspar-rich compositions and heavy-mineral assemblages pointing to contributions from the Higher Himalayan Crystallines (HHC) and Tethyan Sedimentary Sequence (TSS), although long-distance transport, weathering, and hydraulic sorting obscure lithologic specificity. Zircon age spectra reveal diverse age populations sourced from the Namche Barwa syntaxis, Tibetan Plateau, and Lhasa Terrane; however, zircon recycling and overlapping age groups introduce ambiguity in resolving discrete source areas. Sr–Nd isotopic signatures provide a more integrated and transport-insensitive signal, indicating dominant TSS influence with enhanced erosion of the Namche Barwa region during high-magnitude flood events. Together, these proxies demonstrate that each method captures a different scale of sediment input—petrography reflecting local lithologic contributions, zircon ages tracing distal and recycled sources, and Sr–Nd isotopes integrating basin-scale signatures. The multi-proxy approach underscores the need to combine complementary datasets to accurately reconstruct sediment routing, identify erosional hotspots, and comprehend megaflood-driven landscape evolution in the eastern Himalayas.

Globally, people are using more energy, which has led to research into more sustainable energy sources. This research is the investigation of the structural and photometric properties of CaGd1−xAl3O7: xTb3+ (x = 0.03, 0.04, 0.05, 0.06, and 0.07 mol) nanophosphors, with the purpose of economically designing wLEDs. Here, the nanophosphor was created by the solution combustion method, and then its morphological characteristics and crystallite size were thoroughly examined using high-resolution transmission electron microscopy (HR-TEM) and X-ray diffraction techniques. The distinctive green emissions of Tb3+ ions were observed in all samples under 310 nm near ultraviolet light stimulation, which was caused by the 5D4 → 7F5 (543 nm) transition. Investigations into the relationship between PL emission intensity and Tb3+ doping concentration revealed that 4 mol

Weathering is a key driver of global biogeochemical cycles, seawater element flux, and long-term climate regulation via CO2 sequestration, making the understand of in-situ weathering dynamics essential. In thick weathering profiles, tectonic or weathering-induced fractures enhance fluid circulation by increasing permeability and reactive surface area, thereby accelerating mineral breakdown and weathering kinetics. The study highlights the impact of a strike-slip Kaliasaur fault on metabasic rock weathering in the tectonically active Himalaya. The slip behavior and associated shear planes of the fault were traced, and two metabasic weathering profiles were analysed: one developed on the highly fractured rock in the fault damage zone (Bhaldiyana Weathering Profile, BWP) and the other located farther from the fault influence (Pailgaon Weathering Profile, PWP). The dense fracture system associated with the fault has facilitated deep fluid circulation leading to chemical alteration extending to the base of the weathering profile and increasing weathering rates by up to three times. The element loss rates in the BWP are nearly double of those in the PWP, further reinforcing accelerated weathering kinetics due to tectonic fracturing. Notably, the maximum weathering age in BWP (similar to 91 ka from the top 4 m zone) aligns with the published neotectonic activity along the fault, signifying the mixing of exiting strata during faulting, followed by the regime shift to dense fracture system developing rest of the weathering profile. The study shows that the fault has significantly altered the weathering regime by enhancing fracture-driven fluid flow and highlights the importance of integrating structural geology into weathering research in the tectonically active regions like the Himalaya. This study also provides the first in-situ U-series weathering timescales from the Himalaya, bridging a key gap in understanding tectonic-climate-geochemical interactions with implications for other mountain systems.

The climate-tectonic-sea level relationship in an active mountain belt, like the Himalayas and its foreland, can be better understood by delving into the sedimentary stratigraphy of the alluvial tracts developed in the foreland basins. Alluvial fans, in particular, operate as a natural depository of sediments that can be utilized to assess the role of geological processes working between the source and sink. The physiography of these fans, including channel patterns, aggradation, and incision, is influenced by tectonics, sea level variations, and local factors like precipitation and slope, impacting the availability of eroded materials. This study based on geomorphic mapping, detailed sedimentological analysis, lithofacies analysis, and geochemical (Sr-Nd analysis) provenance characterization, as well as optically stimulated luminescence (OSL) ages of a relict alluvial fan, provides a dated sedimentation framework for the western Assam lowland areas. The fan surface lies ~40 m above mean sea level, is incised, and forms a regional valley terrace T1 composed of meandering channel deposits. Modern braided rivers flow on the T0 surface. The findings suggest that the alluvial fan is composed of three distinct lithofacies associations and aggraded during 27 to 3 ka. The bottom-most cross-bedded gravelly-sandy facies (Phase-1) indicate progradation of the fan during LGM, owing to the increased gradient of the Himalaya-bound rivers. Sheet flood deposits (Phase-2) in the middle facies formed during the Late Pleistocene-early Holocene with rising sea levels and increased precipitation. In the Mid-Late Holocene, the uppermost facies (Phase-3) deposited as rivers, responding to elevated sea levels, lost their gradient, leading to inland sedimentation within muddy meandering channels. Modern-day Gravel Sand transition zone lies much upstream of the transverse rivers in comparison to the gravel sand transition zone of the paleofan. This indicates that alluvial fan was prograding in response of increased gradient of the transverse Himalayan Rivers due to lowered sea level during LGM. Our analysis found that falling sea level during the late Holocene was associated with greater precipitation and allowed the river to incise, to form gullies over the fan surface and form the valley terrace T1. The gravel units found in borehole stratigraphy of Upper Bengal Delta (located ~100 m below msl) relate to progradation of alluvial fans in response to lowered sea-level rather than an extreme flood events in axial channel of Brahmaputra as envisaged in earlier study. The provenance fingerprinting using Sr-Nd isotopic composition suggest that the deposits of phase-1 and phase-2 were equally sourced from the Higher and lesser Himalaya while the phase-3 deposit along with the sediments of the meander scroll deposit mimicked the composition of the modern-day bed-load which are dominated by Higher Himalayan sediments.

Provenance fingerprinting of sediments plays a crucial role in identifying erosion hotspots associated with large flood events. In this study, we apply three commonly used source tracing methods-sand petrography, U-Pb zircon geochronology, and Sr-Nd isotopic analysis-to five well-dated sediment samples from a previously studied Holocene paleoflood sequences of the Siang River in the northeastern Himalaya. We compare the outcomes of these methods to evaluate their effectiveness in tracing sediment sources and to discuss their respective strengths and limitations in reconstructing provenance under high-energy flood conditions. Petrographic analysis of quartz, feldspar, and heavy mineral assemblages, suggests sediment input from the Higher Himalayan Crystallines (HHC) and Tethyan Sedimentary Sequence (TSS). However, mineral sorting, weathering biases, and hydrodynamic effects challenge its reliability for long-distance transport tracing. U-Pb zircon chronology reveals distinct age populations, linking sediments to the Namche Barwa syntaxis, Tibetan Plateau, and Lhasa terrain. Yet, zircon recycling, overlapping age distributions, and downstream dilution introduce uncertainties in precise source attribution. Sr-Nd geochemistry provides a cumulative isotopic signature, confirming dominant TSS inputs with significant contributions from Namche Barwa during extreme flood events. Unlike petrography and zircon chronology, Sr-Nd isotopes remain unaffected by mineral sorting and preferential preservation, making them more reliable for large-scale provenance analysis. The discrepancies between methods highlight how each technique captures different aspects of sediment transport: petrography for local, short-term sources, zircon dating for long-distance tracing with potential biases, and Sr-Nd geochemistry for integrated source signals. This study underscores the necessity of a multi-proxy approach to resolve inconsistencies and accurately reconstruct sediment dynamics in megaflood events, providing new insights into erosion patterns in the eastern Himalaya.

Wildfire is an integral component of the terrestrial ecosystem that plays a significant role in regulating the vegetation cover. The paleofire records stored in lacustrine, peat, or marine sedimentary deposits along with environmental proxy records provide temporal information on fire activity and contemporary climatic conditions on a regional scale. A ~2.8m long peat sedimentary profile from Stagmo, Indus Valley, Ladakh Himalaya was examined for sedimentology and charcoal microfossil contents to investigate fire characteristics and reconstruct wildfires which are compared with paleoclimatic changes and past human activities to assess their significance in biomass burning. Charcoal count (CC) analysis provides a suitable method for investigating climatic and vegetation changes with human intervention when no direct evidence is available in the Late-Holocene Trans Himalaya records. The results bring new insight into the interaction between vegetation, fire, and human activity in the Ladakh Himalaya during the past ~2.8 cal kyr BP. An event characterized by high CC at ~2.8 cal kyr BP is distinct from the whole sequence and cannot easily be explained as only the result of a climatic event. This first high charcoal count phase (2.81–2.55 cal kyr BP) could be a natural response to the expansion of forest and dense vegetation with human management interruption. This paleo wildfire event likely corresponds with the time of the Tibetan Plateau’s immediate human occupation. In the second phase, a relatively low charcoal count (1.65–1.54 cal kyr BP) is supported by the high fuel availability during a transitional phase. The third phase of wildfire reconstruction in Ladakh Himalaya is identified at ~1.38 cal kyr BP. This phase can be correlated with the intensified Indian Summer Monsoon (ISM) advancing to Trans-Himalaya leading to increased human settlement in the region.

Variations in lake-levels and hydrology are connected to climatic dynamics over the Trans-Himalaya and Tibetan Plateau (TP). Pangong Tso, a ~140 km long hypersaline lake, is sensitive to changes in air temperature, precipitation and snow-glacier melt over the southwestern TP. The incised tributaries entering the lake expose deltaic sequences constituting topset, foreset and bottomset. Sedimentology, chronology and diatom analysis of delta sediments; and stable isotopic and sclerochronological analysis of gastropods helped delineate the Late-Holocene variation in lake levels, surface temperature and salinity. The elevation of the topsets is considered as representing past lake high-stands from where molluscs were also recovered. Three phased lake level changes are observed during the past 3 ka. The first high-stand (+1.4–3.0 m) was at ~2.8–2.0 ka when lake surface salinity and temperature were 4.67–6.01 ppt (parts per thousand) and 5°C–7°C, respectively, against the modern average values of 7.7 ± 0.09 ppt and 16.1°C ± 2.0°C. Followed by a brief decline, another high-stand (+3.0–3.6 m) is observed at 1.1 ka when the salinity is reduced to 4.03–5.72 ppt and lake surface temperature to 5°C–8°C. A corresponding increase in freshwater diatom concentration is also observed here. The third phase over the past 1 ka witnessed a fall of ~3.6–6 m in lake level that is attributed to an abrupt rise in aridity over the TP. We demonstrate that lake level variation in the region is a function of the variability of the Indian Summer Monsoon (ISM) and the westerlies, however during the high-stand, the hydrology of the lake was dominated by ISM precipitation.

The terrestrial carbon in the forest system endures in multitude form such as organic and inorganic carbon. The carbon pools in the forest ecosystem exist as the below-ground, above-ground biomass and dead organic matter and play a critical function in maintaining carbon cycle and carbon budget of the terrestrial sphere. The Indian Himalayan Forest Ecosystem (IHFE) stores a significant amount of carbon, which is being affected day by day as a result of mismanaged overexploitation. Therefore, the biomass accumulation potential and carbon sequestration capacity of the forest ecosystem are reducing, and it is a key concern as it may contribute the global warming. Consequently, the current breakdown highlights the fragmented information on carbon sequestration potential in the Indian Himalayan Region (IHR). Previous research has also confirmed a significant contribution of terrestrial carbon pools and potential carbon sinks in the IHR. Nonetheless, this deconstruction also has covered the ecological outlook for conservation and guidelines for estimating the IHR's carbon stock potential in forest-based mitigation movements in the Himalayan forest ecosystem.

Packages of fluvial systems in the Lower Ganga plains (LGP) archive the changes in stratigraphic architecture induced by perturbations in the climatic system. In some parts of this landscape, where the fluvial sequences predominate, the role of climate in landsculpting is strongly indicated by the presence of sediment architecture. The present study is focused on the formation of alluvial plains of the Ajay River in the Rarh region that represent a region's environmental templates for understanding the landscape of LGP. The sedimentological, geomorphological, and optically stimulated luminescence (OSL) chronological investigations were attempted to document sedimentation patterns and the timing of deposition. The stratigraphic data from two exposed cliff sections and three boreholes are compared with proxy records to understand the Indian Summer Monsoon (ISM) controls on alluvial sedimentation for the last ~2.4 ka. The fluvial packages in the study area correspond to two significant channel phases: Period‐I (2.4–1.3 ka) and Period‐II (800–200 years ago). Period‐I is characterized by the episodes of floodplain development and lateral migration of the trunk river during Marine Isotope Stage (MIS) I, especially around 2 ka corresponding to the Roman Warm (RW) period in the Indian subcontinent. The sediment filling was high during ~2.4 ka due to ISM intensification, but in the later stage, the sedimentation was at a fairly steady rate. Conversely, Period‐II is characterized by flooding phenomena and aggradation of channel bodies across much of the present valley area during the last 800 years. The distinct flood events occurred during the times of significant shifts in ISM, from fluvial dormancy to sudden outbursts of monsoons (end of Little Ice Age [LIA] ~ 19th century), indicating that climatic patterns can be associated with the occurrences of abrupt flood events. The alluvial records fit well with the historical, instrumental, and published proxy data on the ISM validating the chronology and the potential of sedimentary archives for further studies related to the palaeoenvironment and palaeogeography.

The biomarkers presented in the human breath can lead to the detection of underlying diseases and alcohol detection. The semiconductor-based sensors are well suited for detection of volatile organic compounds (VOCs). The Wolkenstein-based numerical model is used to compute the sensor response of Cu2O-based sensor towards VOCs. The adsorption–desorption equilibrium has been used to compute the sensor response for different concentrations of target gas analytes. The model has been simulated for various temperature range to obtain the optimized operating range of the sensor device. The plot between the normalized electrical conductance and the frequency provided the cut-off frequency (108–109 Hz). This cut-off frequency was further used to analyze the variations in sensor response. The presented design model of the gas sensor device exhibits improved sensor response towards 0.05 atm partial pressure in the operating temperature range of 360–380 K. Further, the operating temperature range of sensor device was found ~ 375 K.

The purpose of this study was to identify the geographic variability and mapping of different soil properties using geospatial techniques at DDUCE-OF Farm. For this purpose, surface soil samples (0-15 cm depth) were collected with the help of GPS at definite locations of research farm area at DDUCE-OF, CCSHAU, Hisar during rabi, 2021. These samples were analyzed in the laboratory for various physico-chemical and biological properties. Soil properties of DDUCE-OF farm revealed that soils are sandy loam to loam in texture having pH ranged from 7.15 to 8.65 and electrical conductivity (EC) ranged from 0.30 to 2.75 dS/m. The soil organic carbon (SOC) content was observed medium to high (0.41 to 0.94%).The available N was low (126 to 196 kg/ha), P ranged from 8.50 to 23.5 kg/ha (from low to high in content) and available K was found medium to high and ranged from 128.5 to 554.0 kg/ha. The available S ranged between 60 to 725 mg/kg and was observed sufficient. The soil microbiological bacterial count status ranged between 4.6x103-9.8x109 CFU count per g of soil in various blocks of organic farm. The DTPA-extractable micronutrients Zn (1.00-4.47 mg/kg), Fe (7.26-19.92 mg/kg), Mn (3.88-17.77 mg/kg) and Cu (0.93-4.64 mg/kg) were sufficient in amount and heavy metal contents (Ni, Pb, Cd, Cr, As) were found below their permissible limit. The study concluded that the soil mapping and survey is significant because it aids in the evaluation of soil qualities and their application in organic farming.

Geomorphic processes coupled with tectonics are responsible for a higher rate of sediment flux and landscape evolution. In this context, the widely used Revised Universal Soil Loss Equation (RUSLE) model has been applied in the upper Shyok river basin, a tributary of the Indus river, which covers an area of ~14 156 km 2 . Rainfall erosivity has been calculated from Center for Hydrometeorology and Remote Sensing rainfall data, soil texture maps from National Bureau of Soil Survey and Land Use Planning (NBSS and LUP) for soil erodibility, Advanced Land Observing Satellite- Phased Array type L-band Synthetic Aperture Radar (ALOS-PALSAR) Digital Elevation Model for slope length and steepness, crop management from pre-post Normalized Difference Vegetation Index in the Google Earth Engine, and support practice through landuse landcover (LULC) classes derived from the European Space Agency. The result indicates that ~21.24 t/ha/year mean soil loss rate has been observed in the Shyok river basin, highest (28.32 t/ha/yr) in bareland LULC classes and lowest in the forest (2.09 t/ha/yr) LULC classes. 11.89% of the study area indicates no erosion since the RUSLE model cannot be used in glacier and snow cover areas. This high rate of erosion is due to the increase in the exhumation rate because of an increase in twofold in Mio-Pliocene in the margin of Tibetan. The geomorphic parameters (e.g. slope, relief) with long-term exhumation rate in the Trans-Himalayan region of India show a statistical correlation.

The gas sensor response of the tin oxide (SnO2) semiconductor toward carbon monoxide (CO) gas has been simulated using the noise spectroscopy technique. The Wolkenstein gas adsorption model is used to calculate the surface coverage of environmental oxygen ions and target gas molecules. The interaction of CO gas molecules with the negatively charged oxygen ions has been incorporated in the numerical model. The equilibrium charge neutrality condition of the semiconductor material has been solved as a function of gas adsorption parameters like surface coverage, temperature, pressure and surface potential. Eventually, the power density spectrum (PDS) of the electrical conductance of the sensing layer was calculated before and after the gas adsorption conditions. It has been observed that the semiconductor band bending increases sharply at a certain concentration of environmental oxygen gas concentration (10-4 to 10-3 atm). At a temperature of 480 K, a steep decrease in surface potential was observed. This temperature range of maximum sensor response was optimized for calculating noise spectrum of electrical conductivity fluctuations at equilibrium condition of adsorption-desorption. The cutoff frequency (109 Hz) was calculated using normalized PDS of electrical conductance. The gas sensor response was calculated as a ratio of film conductance before and after the gas adsorption as a function of gas pressure and surface temperature at the calculated cutoff frequency. The increase in sensor response was observed with the increase in CO partial pressure as a function of temperature for a specific cut off frequency. The comparison of sensor response of the presented model has been demonstrated with another published numerical model. The presented model shows improved sensor response for higher (>10-8 atm) CO partial pressure.

Continent-continent collision between Eurasian and the Indian plate during the Cenozoic period lead to the formation of the Himalayan Mountain chain and the development of the Indus-Ganga-Brahmaputra foreland basin to the south. Complex climate-tectonic interactions in this orogenic belt are responsible for the rapid erosion and filling of the Indus-Ganga-Brahmaputra foreland basin with the eroded materials. This study based on geomorphic mapping, lithofacies analysis, and geochemical (Strontium-Neodymium i.e., Sr-Nd analysis) provenance characterization, as well as optically stimulated luminescence (OSL) ages, provides a dated sedimentation framework for the western Assam lowland areas. The dated relict fan surface lies similar to 40 m above mean sea level (msl), is incised and forms a regional valley terrace T-1 composed of meandering channel deposits. Modern braided rivers flow on the T-0 surface. The findings suggest that the alluvial fan is composed of three distinct lithofacies associations and aggraded during 27 to 3 ka. The bottom-most gravelly-sandy fades indicates progradation of the fan during the last glacial maximum (LGM), owing to the increased gradient of the Himalaya bound rivers. The middle fades is a sheet flood deposit which formed during the Latest Pleostocene-early Holocene period with rising sea level and increasing precipitation. During the Mid-Late Holocene, the uppermost fades is deposited as rivers lost their gradient in response to high sea level stand, resulting in inland sedimentation within muddy meandering channels. Our analysis found that falling sea level during the late Holocene was associated with greater precipitation and allowed the river to incise, to form gullies over the fan surface and form the valley terrace T-1. The Sr-Nd isotope fingerprints have been used to identify varying fan sediment sources in the Himalaya's southern front (i.e., Lesser and Higher Himalaya) as a function of changing monsoon conditions. (C) 2022 Elsevier B.V. All rights reserved.