Validating second-order model for economic welfare scale: evidence from Nigeria

PurposeThe goal of this paper is to validate the second-order model for the economic welfare scale in the context of violence. This study also aims to assess the relationship between the dimensions of the economic welfare scale’ declining food consumption and loss of income and the overall latent construct and assess the second-order model’s goodness of fit using appropriate fit indices.Design/methodology/approachThe study is cross-sectional with a sample of 600 households from the violent zone, Northwest Nigeria. The data collected was used for confirmatory factor analysis, second-order model evaluation and model fit evaluation.FindingsThe second-order model for the economic welfare scale is valid and reliable; the dimensions significantly affect the formation of the overall construct. The model’s goodness of fit fulfilled the relevant fit indices.Research limitations/implicationsThe study offers researchers and policymakers practical insights into how each dimension influences the latent operational construct. It, therefore, encompasses replication in all the remaining modules.Practical implicationsThe findings offer practical insight to policymakers in designing policies for promoting long-term peace structures and developing mechanisms to assist those who have suffered the greatest economic welfare losses due to violence in Nigeria.Social implicationsThe findings form an essential tool to assess the economic welfare effect in violently affected territories at the micro-level.Originality/valueThe outcomes are ground-breaking by validating the second-order model for the economic welfare scale. And established dimension influences over the overall latent variable.

Green Synthesis of Nanostructure CeO2 Using Tea Extract: Characterization and Adsorption of Dye from Aqueous Phase

Nanostructure CeO2 powders were synthesized using tea waste extract as gel precursor. The as-prepared samples were characterized by thermogravimetric analyzer (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Based on the TGA/DTG analysis, the intermediates of cerium chloride hydrates (CeCl3.4H2O and CeCl3.H2O) and cerium anhydrous (CeCl3) were produced, and the formation temperature of CeO2 was estimated to be 773 K. The cubic fluorite structure of CeO2 was detected to be the predominant species and was completely formed at the calcination temperature of 773K–1073 K with a crystal size between 8.8 and 11.4 nm based on the XRD measurement. Moreover, the main chemical state of ceria on the surface of the synthesized samples was confirmed to be tetravalent ceria by XPS. All samples show a strong Raman signal at a well-defined chemical shift of 463 cm−1 and a significant symmetry feature was observed, suggesting that the tetravalent ceria is the dominant species throughout the bulk sample. All the synthesized CeO2 calcined at different temperatures showed higher adsorption efficiency for Congo red (CR) compared with commercial CeO2. The adsorption efficiency maintained a steady state of more than 95% when the concentration of CR and adsorption temperature were varied in this study. The kinetic analysis showed that the second-order model was the appropriate model to interpret the adsorption behavior of synthesized CeO2. The calculated adsorption capacity derived from the second-order model is in good agreement with the experimental data. The isotherm analysis revealed that the Freundlich and D-R models fit well for the synthesized CeO2 and represent physisorption with a multilayer mechanism. The thermodynamic parameters, including the changes in Gibb’s free energy, enthalpy, and entropy, suggested that the adsorption of CR on the synthesized CeO2 sample was a spontaneous and endothermic process.

Performance evaluation and substrate removal kinetics in a thermophilic anaerobic moving bed biofilm reactor for starch degradation

A laboratory-scale anaerobic moving bed biofilm reactor (AnMBBR) was installed and operated at various hydraulic retention times (HRTs) of 20 to 1.5 d with surface area loading rate (SALR) of 0.86 to 11.43 gCOD/m2/d. Synthetic starch containing desizing wastewater with chemical oxygen demand (COD) of 12.75 g/L was prepared and fed into the reactor. Monod, modified Stover-Kincannon, Grau second-order and First-order substrate removal models were used to evaluate the results of AnMBBR. COD removal efficiency of bioreactor was dwindled by increasing the SALR or reducing the HRT. Decay coefficient (Kd) and yield coefficient (Y) for Monod model were 0.027 1/d and 1.01 mgVSS/mgCOD, respectively. Maximum substrate utilization rate (Umax) and kinetic constant (Kb) for Modified Stover-Kincannon model were estimated as 12.57 and 15.22 g/L/d, respectively. The constants (a and b) for Grau second-order model were found to be 1.09 and 1.31 whilst kinetic coefficient for Second-order model and First-order substrate removal model were 1.62 and 1.55 1/d, respectively. Modified Stover-Kincannon model and Grau second-order model were found to be the best fit for experimental data with R2 value of 0.99. The findings suggest that these models can be applied to predict the behaviour of AnMBBR on various scales.

Characterization of Cr(III) interaction with kaolinite – Effect of the presence of Cr(VI)

In the present study, experiments were performed to characterize the effectiveness of kaolinite in Cr(III) removal from water in the absence and in the presence of Cr(VI). The results of batch experiments, show that the efficiency of Cr(III) removal by kaolinite increases with the increase of pH and temperature in both cases. The effect of the presence of Cr(VI) on the adsorption of Cr(III) by kaolinite depends on the solution pH and on the concentrations of the two ions. Whatever the system, the removal kinetic of Cr(III) is well described by the pseudo-second order model. Spectroscopic analyses reveal that Cr(III) interaction with kaolinite is mainly electrostatic.

Overshoot of D-dot sensor in measurement of electric field

This paper analyzes the cause of the overshot of the signal measured by D-dot sensor, and points out that the second-order RLC equivalent circuit model can explain the overshot Taking the asymptotic conical antenna as an example, the inductance L of the second-order model is obtained by using CST simulation and Pspice parameter scanning method. The first-order model and the second-order model are used to calculate the electric field waveform. Under the given conditions, the first-order model is used to obtain the electric field waveform, the waveform overshot is serious, the maximum overshoot reaches 27%, while the second-order model is used to improve the ringing phenomenon, And the maximum overshoot is reduced to 5%.The results show that the second-order model is more accurate than the first-order model and can improve the precision of electric field measurement using D-dot sensor.

Utilization of Macadamia Nutshell Residue for the Synthesis of Magnetic Activated Carbon toward Zinc (II) Ion Removal

In this study, macadamia nutshell residue, a prevalent leftover and green agricultural waste in Vietnam, was utilized to prepare a magnetic activated carbon adsorbent. The obtained material was characterized by its surface functionalities, elemental composition, crystalline structure, and magnetic properties. The characterization results revealed that the composite comprised Fe3O4 nanoparticles attached to the carbon matrix. The saturation magnetization (Ms) of the composite was found to be 38.2 emu g−1, indicating a convenient separation of the solid adsorbent from aqueous media using an external magnetic field. The feasibility of removing zinc (II) ion from an aqueous solution of the activated carbon/Fe3O4 (AC/Fe3O4) composite was examined. The adsorption kinetics were best explained by the Elovich model and the pseudo-second-order model. The adsorption capacity at equilibrium and the initial rate of Zn2+ adsorption determined by the pseudo-second-order model were 22.73 mg g−1 and 4.18 mg g−1 min−1, respectively. The implications of this study are that a low-cost, green, and magnetically separable material prepared by a large-scale available solid waste can be a promising adsorbent for the elimination of heavy metals.

Comparison of Non-Linear and Linear Ho Models Applied for Copper Ions Sorption on Geopolymer

The Ho pseudo-second-order model is the best fitting model in describing the sorption of copper ions on synthesized geopolymer for the selected experimental conditions (particle size 0.071–0.090 mm at agitation speed of 240 rpm). For that reason, a comparison of one non-linear and five linear forms of the Ho pseudo-second-order model was made in the present study in order to obtain the optimum sorption kinetic parameters using the experimental kinetic data obtained for the copper ions sorption process on the synthesized geopolymer. Taking all the results into consideration, the non-linear Ho model proved to be more consistent in describing the copper ions sorption on geopolymer for various initial concentrations of sorbent, as well as for various temperatures.

Removal of Congo Red by Silver Carp (Hypophthalmichthys molitrix) Fish Bone Powder: Kinetics, Equilibrium, and Thermodynamic Study

Powdered form of bones of silver carp fish, an available species in Bangladesh, was investigated as a prominent bioadsorbent for the removal of Congo red from synthetic solution. Experiments were conducted in batch process, and a number of influencing parameters, such as solution pH, adsorbent dosage, contact time, and initial Congo red concentration, were thoroughly investigated for optimization. Kinetic and equilibrium data were well described by pseudo-second-order model and Langmuir isotherm, respectively. Suitability of pseudo-second-order model to best fit with the adsorption process was corroborated by squared sum of errors analysis. Mass transfer mechanism was confirmed by intraparticle pore diffusion and Bangham’s diffusion models. Maximum sorption capacity of fish bone powder was found to be 666.67 mg·g−1. The optimum condition (adsorbent dose: 5 g·L−1; pH: 2.0; operating time: 4 h) for maximum sorption was determined as well. The increasing negative value of Gibbs free energy (ΔG) with temperature rise indicated spontaneous nature and feasibility of adsorption. The positive values of ΔH and ΔS suggested that the adsorption reaction is endothermic and random (at the solid/liquid interface) in nature. The activation energy (29.84 kJ·mol−1) indicated that the sorption process was of physisorption type. A considerably high adsorption capacity pointed towards utilization of this apparently useless biomaterial as an effective adsorbent.