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Tackling toxicity and stability using eco-friendly metal-halide ion substituted perovskite nanocrystals for advanced display color conversion
No full textIn recent years organic–inorganic hybrid halide perovskites nanocrystals have made a remarkable impact in
display color converting layer application. However, lead toxicity and stability issues always pose arduous
challenges. In this regard, the incorporation of a suitable metal ion to reduce toxicity and enhance stability is a
widely tested method. In this study, we used a simple ligand-assisted reprecipitation (LARP) technique to
simultaneously introduce metal ion and halide ion substitution by synthesizing MAPb1-xZnxBr3-2xCl2x nano-
crystals (NCs). Being eco-friendly with a smaller ionic radius than lead ion, zinc metal ion was chosen as a
substitute. With the variation of Zn2+ concentration, the highest quantum yield of 95 % was recorded with an
emission width of 21 nm. Temperature-dependent photoluminescence (PL) studies revealed the higher optical
phonon-exciton interaction after Zn2+ incorporation leading to radiative transition in NCs. Variation of PL peak
energy with temperature revealed the reduced thermal chromaticity of Zn2+ incorporated NCs making them
suitable for display application. Further, these NCs maintained a stable cubic structure and luminescence up to
150 ◦ C, indicating higher thermal stability. The MAPb0.9Zn0.1Br2.8Cl0.2 (x = 0.1 or 10 mol%) NCs embedded in
PMMA (poly (methyl methacrylate) polymer matrix coated LED emits narrow width, green light with color
coordinate (0.15, 0.79), which is closer to green coordinate (0.17, 0.79) in Rec.2020. This helps to reproduce
close to 97 % color gamut of Rec.2020. This research paves the way for finding less toxic and stable green light-
emitting materials instead of cadmium-based molecules
Experimental investigation, non-isothermal kinetic study and optimization of oil shale pyrolysis using two-step reaction network: Maximization of shale oil and shale gas production
No full textProduction of petroleum from pyrolysis of oil shale could offer a solution to meet the current high energy demands. In this respect, optimizing reaction-dependent parameters during pyrolysis kinetics is crucial for achieving this goal commercially. Thus, in this study, experimental pyrolysis of oil shale samples was conducted in the temperature range of 270–495 °C, with the reaction time of 10–235 min, and a heating rate of 2 °C/min in a fixed bed reactor. Composition and weight of different hydrocarbon fractions (bitumen, shale oil, shale gas, water, and char) based on the reaction pathways were measured. Desired reaction conditions to achieve the maximum petroleum production from the pyrolysis reactions were specified based on the design of the experiment (DOE) following response surface methodology (RSM). Empirical correlations were developed for the prediction of the amount of shale oil and gas, by considering the reaction time, reaction temperature and the char amount as the main governing factors. For the first time, multi-objective optimization was applied to determine the optimal operational parameters, with the aim of maximizing petroleum production. Finally, mass balance equations coupled with second order reactions based on two-step pyrolysis reaction pathway (intermediate bitumen as the transition fraction) were implemented for kinetic modeling. Statistical and graphical evaluations of the kinetic model as well as the proposed correlation, verified an excellent agreement between the models and the experimental composition of pyrolysis products. Moreover, multi-objective optimization revealed that a concurrent maximum shale oil (1.92 gr) and gas (5.72 gr) production from the oil shale (20 gr), reaction temperature, reaction time, and char amount of 457.34, 198.356, and 16.385, would be the optimized reaction-dependent factors. Interactive plots indicated that interactions between time and temperature are not significant for pyrolysis reaction; however, there is a single intersection point between the reaction temperature-char weight and the reaction time-char weight. This, delineated that reaction time (t > 190 min), reaction temperature (T > 440 °C) and higher values of char amount (24.4 gr) would be more favorable to attain higher oil production. Optimal reaction temperature, time, char amount for the maximum oil (5.72 %) and gas (1.92 %) production would be 457.34 °C, 198.35 min, 16.38 %, respectively, while conversion of kerogen to intermediate bitumen (preliminary step) followed by the oil production from the intermediate bitumen (secondary step) were found to be the most significant reactions taking place during pyrolysis. Finally, reaction temperature and time would have a positive relationship with the production of desired yield, while char amount has an inverse relationship with these outputs. Overall, this study should provide specific guidelines for implementing in-situ pyrolysis operations underground in immature organic-rich shale and coal beds
Experimental and molecular simulation of carbon dioxide solubility in hexadecane at varying pressures and temperatures
No full textCO2-EOR can make underground storage efforts possible, addressing both energy demands and climate issues. This study establishes an in-situ method to measure the degree of CO2 solubility in hexadecane in a wide range of P-T conditions. CO2 and hexadecane with known volumes were mixed in silica capillaries and examined by Raman spectroscopy after reaching an equilibrium at certain P-T condition to establish a relationship between mole fraction of CO2 in hexadecane and ratio of Raman peak area. Results showed that solubility of CO2 decreases with increasing temperature and increases with pressure. Complementing the experimental data, hybrid grand canonical Monte Carlo/molecular dynamics (GCMC/MD) simulations were performed to study the swelling effect of CO2/hexadecane system and the diffusion of CO2 within hexadecane. Simulation results were validated against Raman spectroscopy and previously published CO2 solubility data, as well as a genetic algorithm-based (GA) predictive model, all matching with high accuracy and conforming each other. Based on molecular simulation results, the necessity of accounting for volumetric changes in solubility calculations to enhance the accuracy of predictive models in similar systems was revealed. Additionally, in contrast to temperature, the effect of pressure on the diffusion coefficient remains relatively minimal. Ultimately, this study provides solutions for in-situ probing techniques to determine the solubility of various fluids in a wide range of P-T conditions, processes supporting CO2-EOR and carbon storage operations underground
Infusion of fly ash in alkali salt promoted MgO-based sorbent for CO2 capture at elevated temperatures
No full textCarbon capture at elevated temperatures (200-450°C) using MgO-based solid sorbents, typically suffers from slow kinetics and premature saturation lowering the overall uptake performance. A key factor responsible for this is the agglomeration of MgCO3 during carbonation, which could be potentially overcome by the addition of inert along with promoters. In this context, this work systematically investigates the infusion of Fly ash (FA) as inert in pure MgO and alkali-salt-promoted MgO-based sorbents prepared by the sol–gel method. The study includes characterizing the prepared sorbents based on morphological and textural properties and investigating the uptake kinetics along with cyclic performance based on thermogravimetric analysis under conditions of 250°C and 300°C for 45 mins. Among all tested modified sorbents, MgO_10NaNO3_5FA exhibited the highest uptake capacity of 14.56 mmol/g (MgO basis) followed by MgO_15NaNO3 (14.27 mmol/g) at 300°C. Cyclic studies over 10 cycles reveal higher conversion of FA-infused sorbent (MgO_10NaNO3_5FA: 59.76 %) over non-FA-infused sorbent (MgO_10NaNO3: 54.50 %) showing higher stability of the former. The results establish minimal FA infusion (5 %) in alkali nitrates promoted sorbent favorable for CO2 capture at moderate temperature while elucidating physicochemical aspects during uptake
A comprehensive review on phytoremediation of fly ash and red mud: exploring environmental impacts and biotechnological innovations
No full textFly ash (FA) and red mud (RM) are industrial byproducts generated by thermal power plants and the aluminum industry, respectively. The huge generation of FA and RM is a significant global issue, and finding a safe and sustainable disposal method remains a challenge. These dumps contain harmful trace elements that have a significant impact on the environment and human health. It contributes to air, water, and soil pollution, disrupting the delicate balance of the ecosystems. It also introduces toxins into the food chain through biomagnification. Utilizing a vegetation cover can assist in addressing environmental health concerns associated with FA and RM dumps. Nevertheless, the presence of alkaline pH, toxic metals, the absence of soil microbes, and the pozzolanic properties of both FA and RM pose challenges to plant growth. Taking a comprehensive approach to the ecological restoration of these dumps through phytoremediation is crucial. This review examines the role of various factors in the ecological restoration of FA and RM dumps, specifically the use of naturally occurring plants. However, the issue of slow plant growth due to a lack of nutrients and microbial activities is being resolved through various advances, such as amendments in conjunction with organic matter, microbial inoculants, and the use of genetically modified plants. Research has demonstrated the benefits of using amendments to stimulate vegetation growth on FA and RM dumps. In this review, we explore various approaches to restoring FA and RM dumps and transforming them into productive sites that enhance the ecosystem services
Assessing the effects of early and timely sowing on wheat cultivar HD 2967 under current and future tropospheric ozone scenarios
No full textThis study investigates the impact of elevated ozone (eO3) levels on the growth and yield of the wheat cultivar HD 2967 under different sowing dates in open-top chambers. Wheat was sown early on November 1st and timely on November 20th, 2017, under ambient and elevated O3 (ambient + 20 ppb), resulting in four treatment groups: AT (ambient + timely), ET (elevated + timely), AE (ambient + early), and EE (elevated + early). Results showed significant reductions in morphological traits and gas-exchange parameters, including photosynthetic rate, stomatal conductance, and water use efficiency under eO3. The most notable decreases were observed 40 days after germination (DAG) compared to 80 DAG. Interestingly, while a higher percentage reduction was observed under ET at 80 DAG, a reversal in the trend of percentage reduction between the two stages was noted, suggesting a dynamic response of the wheat cultivar to stress across the growth stage. However, compared with ET's results, early sowing mitigated these negative effects under a futuristic O3 level scenario, showing no significant impact on grain yield and productivity factors. This resilience is attributed to the extended growth period, enhancing photosynthesis and biomass accumulation while avoiding high eO3 concentrations during critical reproductive stages. Furthermore, a trade-off in ET plants suggests resources are allocated towards defense (enzymatic and non-enzymatic antioxidants) at the expense of growth, while EE conditions favor growth at later stages, maintaining reproductive fitness despite eO3 levels. Under conventional timely sowing, wheat may suffer yield declines of up to 30 % amidst rising eO3 levels. Early sowing emerges as a proactive strategy to maintain wheat productivity under increasing O3 stress. Future studies should explore the effectiveness of early sowing across multiple wheat cultivars and climatic conditions to inform sustainable agricultural practices in high O3 areas
Dump truck activity recognition using vibration signal and convolutional neural network automation in construction
No full textUtilization of Natural Zeolite (Scolecite) to Reduce Arsenic Contamination of Water in Relation to Machine Learning Approach
No full textAmong heavy metals, arsenic contamination in water resources is a major concern due to its harmful effects on human health as slow poison behaviour affecting many states of India and at global level. The present study is about efficiency of Scolecite (CaAl2Si3O10.3H2O), a natural zeolite mineral, to remove arsenic contamination from water. The arsenic-contaminated water samples were collected from both industrial areas and non-industrial areas which include Singrauli industrial sites of Madhya Pradesh/Uttar Pradesh, Jalangi Block and various thermal power station areas of West Bengal, Kaudikasa-Rajnandgaon district of Chhattisgarh and Kakching area of Manipur. After conducting rigorous experimental studies, it was observed that the collected water samples had been reduced up to below 10 ppb within the permissible limit of WHO in 7 days with different quantities of scolecite (as 0.5 g/50 ml, 2.5 g/50 ml, 5 g/50 ml and 10 g/100 ml). The reduction of arsenic and the absorbing properties were identified as negative charge developed on the crystal face of Si3Al3 in scolecite. The XRD analysis of filtrate, which remained after filtration of samples prior to chemical analysis for arsenic concentration, is that specific hkl faces (i.e. 111, 040, 132, 400 and 240) are more affected in increase of pH in scolecite-treated water samples and hence play a major role in arsenic removal. The adsorption efficiency of arsenic (As) from water samples was predicted in the present study using an artificial neural network (ANN) model and perceived that the smallest quantity of scolecite may reduce higher amount of As in proportionate water samples
Highly efficient and stable NiSe2-rGO composite-based room temperature hydrogen gas sensor
No full textThe widespread consumption of hydrogen in commercial and industrial applications has resulted in the devel-
opment of different hydrogen gas sensors. However, their practical application is restricted due to their non-cost
efficiency, low sensitivity, poor selectivity and high temperature sensing properties. Thus, the development of a
sensor capable of overcoming the aforementioned limitations is critical for commercial deployment. As a result, a
NiSe2-rGO composite-based H2 gas sensor has been prepared for the first time using a simple hydrothermal
technique. The developed material has been systematically characterized for its morphological properties and
thoroughly investigated for H2 gas sensing applications. The findings show that the developed NiSe2-rGO
composite exhibited enhanced H2 gas sensing properties, besides possessing appreciable selectivity, repeatability
as well as long-term stability. Furthermore, the results demonstrate a stable sensor response of 254% within 43 s
and 13 s of response and recovery time respectively at a hydrogen concentration of 500 ppm which is 8 and 500
times higher than that of its individual counterparts (NiSe2 and rGO) over a wide relative humidity range,
indicating the material’s potential for application in industrial environments. Thus, this work paves the way for
the development of stable, effective, fast-responding, and selective hydrogen gas sensors that are functional at
room temperature
Study on sequence stratigraphy in the Permian sediments of terrestrial sequences within the Chintalapudi sub-basin, Godavari Coalfield, Southern India: insight from palynology and geochemistry
No full textThe opening of Neo-Tethys within Gondwanaland during the Guadalupian (transition signified a pivotal transgressive event) in the Permian Period. Consequently, an attempt has been undertaken to elucidate the sequence stratigraphy and palaeodepositional settings of fluvial sedimentary deposits encompassing coal and shale sediments within the Godavari Valley Coalfield, South India. The Total Organic Carbon (TOC) content across the examined samples exhibits a discernible range from 0.07 to 65.53 wt%, with reactive carbon, measured as Pyrolyzable Carbon (PC), displaying variations from 0.02 to 15.93 wt% and non-reactive carbon, characterized, as Residual Carbon (RC), spans a percentage range of 0–66.86 wt% within the selected samples. The predominant organic matter manifests as type III kerogen, except Sh-47, where type II kerogen is identified. The combination of Rock–Eval pyrolysis alongside palynofacies analysis facilitates the differentiation of significant system tracts arising from relative sea level fluctuations within the deposited terrestrial sequences. These tracts include swampy and flooded palaeomires settings. Terminologies denoting system tracts within the sequences are indicted as T-lst, T-hst, T-tst and T-mfs corresponding to the Low Stand System Tract (LST), High Stand System Tract (HST), Transgressive System Tract (TST) and Maximum Flooding Surface (MFS) respectively. A noteworthy one and half cycles are discerned within the sequence, predicted on Amorphous Organic Matter (AOM), TOC, Hydrogen Index (HI), PC and Gelification Index (GI) values. In the initial cycle, T-mfs is identified based on the preponderance of fluorescent AOM, coupled with the highest value of HI and PC. The ratio of opaque/translucent phytoclasts serves as a discriminant in delineating the boundaries of T-lst, T-tst and T-hst within the sequences, corroborating the aforementioned observation. This research serves as a preliminary assessment of the system tracts within fluvial environments. A more intricate, high-resolution exploration of deeper sequences holds the potential to furnish comprehensive insights for subsequent studies