Search for: All records

Abstract Washing crude epoxidized oil is an indispensable step for the removal of residual acetic acid and unreacted hydrogen peroxide after epoxidation. There are many studies on the epoxidation of vegetable oils but there are many discrepancies in the washing process which likely leads to water wastage, excess use of neutralizing agent, and additional processing time. Hence, this study aims to optimize the washing step by analyzing the quality of each washing step and developing a model that can predict the amount of acid removed. Soybean oil (1.5 kg) was epoxidized at 60°C for 5.5 h using Amberlite IR 120H as a heterogeneous catalyst. To determine the optimum water washing level, process parameters such as number of washing cycles (1–5), proportion of epoxidized oil to water volume (1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5), and water temperature (20, 40, and 60°C) were examined. The main responses were the residual acid value and pH of the washed epoxidized oil. Results revealed that 64% of the acid was removed after 5 washing cycles irrespective of the washing water temperature and proportion. In contrast, approximately 57% of the acid was removed in the first two washing cycles. Increasing the temperature of the water affected acid removal; with approximately 54% of acid removed at 20°C compared to 60% at 60°C. Doubling or tripling the amount of water needed above a 1:0.5 ratio did not significantly affect the amount of acid removed. The model developed was significant with a predictedR²of 96% and a root mean square error (RMSE) of 1.1 when the model was validated at different washing scenarios. Therefore, this study shows that it is possible to significantly reduce the amount of water used and processing time while maintaining resin qualities. 

A statistical water balance and time series modeling framework is developed to analyze and forecast the Missouri River’s monthly flow at Bismarck from 1954 to 2024. Integrating traditional hydrological components precipitation, evaporation, upstream inflow, tributaries with ARIMA and SARIMA models enable detection of long-term and seasonal trends. Model fit is rigorously assessed by AIC, AICc, BIC, Nash-Sutcliffe Efficiency, and visual diagnostics with credible intervals. Stationarity is evaluated through ADF and KPSS tests to guide model selection. The final SARIMA framework, incorporating Box-Cox transformation and outlier adjustment, produces reliable forecasts with quantified uncertainty for both typical and extreme hydrologic conditions. These forecasts are vital for river management and policy, demonstrating how statistical rigor and visual assessment underpin adaptive water management strategies. 

The application of oxygen-deficient perovskites (ODPs) has attracted interest as anode materials for lithium-ion batteries for their unique properties. One such material, CaSrFe0.75Co0.75Mn0.5O6-δ, has been studied extensively. The structure of CaSrFe0.75Co0.75Mn0.5O6-δ was investigated using various techniques, including Rietveld refinements with X-ray diffraction and neutron diffraction. Additionally, iodometric titration and X-ray photoelectron spectroscopy were employed to study the oxygen-deficiency amount and the transition metal’s oxidation states in the material. As an anode material, CaSrFe0.75Co0.75Mn0.5O6-δ exhibits promising performance. It delivers 393 mAhg−1 of discharge capacity at a current density of 25 mAg−1 after 100 cycles. Notably, this capacity surpasses both the theoretical graphite anode capacity (372 mAhg−1) and that of the calcium analog reported previously. Furthermore, the electrochemical performance of CaSrFe0.75Co0.75Mn0.5O6-δ remains highly reversible across various current densities ranging from 25 to 500 mAg−1. This suggests the material’s excellent stability and reversibility during charge–discharge cycles, showing its probable application as an anode for lithium-ion batteries. The mechanism of lithium intercalation and deintercalation within CaSrFe0.75Co0.75Mn0.5O6-δ has also been discussed. Understanding this mechanism is crucial for optimizing the battery’s performance and ensuring long-term stability. Overall, this study highlights the significant potential of oxygen-deficient perovskites, particularly CaSrFe0.75Co0.75Mn0.5O6-δ, for applications as an anode material for lithium-ion batteries, offering enhanced capacity and stability compared with traditional graphite-based anodes. 

The perovskite oxides CaMnO3-δ, Ca0.5Sr0.5MnO3-δ, and SrMnO3-δ were synthesized in air using a solid-state method, and their structural, electrical, and electrocatalytic properties were studied in relation to their oxygen evolution reaction (OER) performance. Iodometric titration showed δ values of 0.05, 0.05, and 0.0, respectively, indicating that Mn is predominantly in the 4+ oxidation state across all materials, consistent with prior reports. Detailed characterization was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), iodometric titration, and variable-temperature conductivity measurements. Four-point probe DC measurements revealed that CaMnO3-δ (δ = 0.05) has a semiconductive behavior over a temperature range from 25 °C to 300 °C, with its highest conductivity attributed to polaron activity. Cyclic voltammetry (CV) in 0.1 M KOH was employed to assess OER catalytic performance, which correlated with room-temperature conductivity. CaMnO3-δ exhibited superior catalytic activity, followed by Ca0.5Sr0.5MnO3-δ and SrMnO3-δ, demonstrating that increased conductivity enhances OER performance. The conductivity trend, CaMnO3-δ > Ca0.5Sr0.5MnO3-δ > SrMnO3-δ, aligns with OER activity, underscoring a direct link between electronic transport properties and catalytic efficiency within this series. 

This study presents a detailed investigation of the microstructure of the oxygen-deficient perovskite material Ca2FeGaO6-δ using Scanning Electron Microscopy (SEM). The material exhibits significant porosity and irregular grain morphology, with variations in grain size and growth. Unlike conventional perovskite structures, Ca2FeGaO6-δ shows non-uniform grain development, which can be attributed to the presence of oxygen vacancies (δ ). SEM analysis reveals that the irregularities in grain size and shape, coupled with the porous nature of the material, are likely to influence its functional properties. These findings provide valuable insights into the structural features of Ca2FeGaO6-δ , offering a foundation for understanding its potential applications in catalysis, sensors, and other technologies. The study highlights the critical role of microstructural characteristics in determining the material’s performance. 

This study investigates the thermoelectric properties of Ca2Fe2O5 over a temperature range of 7˚C to 50˚C. The experiment measured the voltage generated by temperature differences across two sides of the material, with a focus on the voltage response at temperatures both below and above room temperature. Results indicate that at lower temperatures (7˚C to 15˚C), the voltage generated by the temperature difference was higher, though not directly proportional to the magnitude of the temperature gradient. The highest voltage recorded for the smallest temperature difference in this range was 109 mV, observed between 14.6˚C and 17.6˚C (smallest temperature difference, 3˚C). Similarly, at temperatures above room temperature, the voltage generated was relatively lower, peaking at 125 mV between 9˚C and 44˚C (higher temperature difference). These results suggest complex behavior of Ca2Fe2O5’s thermoelectric response, with non-linear relationships between voltage and temperature differences at both low and high temperatures. 

This study presents a novel and facile technique for the rapid and sensitive detection of zinc (Zn) in foods and drinking water. The need for a reliable method to monitor Zn levels in consumables is crucial due to its significance in both nutritional assessment and environmental safety. The proposed technique integrates state-of-the-art sensing technology with an easy-to-implement approach, aiming to provide an efficient solution for Zn detection. The methodology involves the utilization of complexation of Zn2+ ion with resorcinol and use of UV-vis spectrophotometry, which demonstrates high sensitivity towards Zn2+ ions. It detected zinc up to 10-5M solution. 

In this study, we investigate the utility of Ca₂FeMnO_6-δand Sr₂FeMnO_6-δas materials with low thermal conductivity, finding potential applications in thermoelectrics, electronics, solar devices, and gas turbines for land and aerospace use. These compounds, characterized as oxygen-deficient perovskites, feature distinct vacancy arrangements. Ca₂FeMnO_6-δadopts a brownmillerite-type orthorhombic structure with ordered vacancy arrangement, while Sr₂FeMnO_6-δadopts a perovskite cubic structure with disordered vacancy distribution. Notably, both compounds exhibit remarkably low thermal conductivity, measuring below 0.50 Wm⁻¹K⁻¹. This places them among the materials with the lowest thermal conductivity reported for perovskites. The observed low thermal conductivity is attributed to oxygen vacancies and phonon scattering. Interestingly as SEM images show the smaller grain size, our findings suggest that creating vacancies and lowering the grain size or increasing the grain boundaries play a crucial role in achieving such low thermal conductivity values. This characteristic enhances the potential of these materials for applications where efficient heat dissipation, safety, and equipment longevity are paramount. 

The thermal conductivity of CaSrFe2O6-δ, an oxygen-deficient perovskite, is a critical parameter for understanding its thermal transport properties and potential applications in energy conversion and electronic devices. In this study, we present an investigation of the thermal conductivity of CaSrFe2O6-δ at room temperature for its thermal insulation property study. Experimental measurement was conducted using a state-of-the-art thermal characterization technique, Thermtest thermal conductivity meter. The thermal conductivity of CaSrFe2O6-δ was found to be 0.574W/m/K, exhibiting a notable thermal insulation property.