Soran University

The selection of an appropriate Sequential Excavation Method (SEM) strongly affects tunnel stability, costs, and project schedules. Existing predictive approaches often rely on parameters that are difficult and time-consuming to determine, particularly in small-scale projects, and their accuracy is limited compared with actual excavation practices worldwide. This study introduces a practical decision-making graph to support SEM selection. Two empirical correlations from laboratory and field studies were used to generate input parameters for numerical modeling, and 672 simulations were performed to construct the graph, which is based on tunnel span and the axial failure strain of the ground. The graph’s validity was evaluated using a confusion matrix for 96 tunnel projects, yielding 100

This study systematically examines the influence of glycerol (9-45 wt%) as a plasticizer on the structural, physicochemical, and electrochemical properties of chitosan-dextran-LiClO4-Al2O3 nanocomposite polymer electrolytes prepared by solution casting. Electrochemical impedance spectroscopy revealed a pronounced reduction in bulk resistance from 64,310 Omega to 160 Omega and an increase in ionic conductivity from 0.04 to 18.10 mu S cm-1 (over 450-fold). The relaxation time (tau) decreased from 1441.49 to 4.18 mu s, indicating accelerated ion reorientation and enhanced charge-carrier mobility at higher glycerol content. FTIR analysis evidences strong hydrogen-bonding interactions among polymer hydroxyl/amine groups, Li+ ions, and Al2O3 nanoparticles, which promote salt dissociation and complex formation. Increasing glycerol content also elevated the dielectric constant (epsilon ') and dielectric loss (epsilon ''), reflecting intensified dipolar and interfacial polarization and a higher mobile charge density. Glycerol augmented the amorphous fraction and segmental mobility, thereby facilitating ion transport. The optimized CS-Dextran-LiClO4-Al2O3-glycerol film demonstrates significantly improved ionic and dielectric performance, making it a promising solid polymer electrolyte for advanced electrochemical and energy-storage applications.

This study systematically investigates the role of glycerol concentration as a plasticizer in controlling structure–ion transport relationships in methylcellulose (MC)–dextran–sorbitol nanocomposite polymer electrolyte (NPE) films doped with lithium nitrate (LiNO3, 38 wt

This study evaluates the performance of self-compacting geopolymer concrete (SCGC) incorporating fly ash (FA), ground granulated blast furnace slag (GGBFS), and recycled concrete aggregates (RCA). Five SCGC mixtures with varying RCA content (0

In this study, hydroxyapatite (HAp) samples, co-doped with 0.44 at.% of zinc and different amount of quercetin (Zn/Que-HAp), were synthesised using a wet-chemical method and calcined at 900°C. XRD shows HAp as the primary phase with minor β-TCP. Compared to the Zn-doped sample without quercetin (Q1), quercetin co-doping induces clear structural changes (shifts of lattice parameters a from −0.0017 to +0.0006 nm and c from −0.0026 to −0.0005 nm), accompanied by changes in crystallinity (from −3.6% to +2.5%) and crystallite size (from −3.5 to +0.6 nm), evidencing a distinct co-doping effect. DTA/TGA reveal reduced total mass loss for the Que-containing compositions relative to the Zn-doped sample, indicating enhanced thermal stability of the co-doped lattice. SEM reveals granular morphologies with interconnected porosity, while EDX yields (Ca+Zn)/P ratios greater than 1.67, consistent with Ca-sufficient apatite and modified defect chemistry. DFT calculations resolve the site-specific effects of Zn substitution and predict a preference for perturbation at Ca2 sites. The electronic density of states retains a wide-gap, insulating character, with localised states sensitive to the dopant configuration. By correlating experiment and theory, we demonstrate that the organic-inorganic co-dopant pair offers an effective means to tune lattice metrics, phase balance, and thermal response without compromising the intrinsic insulating nature of HAp.