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An innovative hybrid hydrogen generator using photoelectrochemical and electrolysis processes: Experimental study
No full textHydrogen is widely recognized as a clean and sustainable energy carrier in response to the growing demand for sustainable energy sources. Photoelectrochemical (PEC) water splitting offers a promising method for directly generating waterfrom solar energy with minimal environmental impact. The present study introduces a newly designed hybrid version of PEC-conventional electrolysis system which uniquely manages the most beneficial features of both PEC and conventional electrolysis technologies, thereby offering an improved operational performance. The ability to continuously generate hydrogen, regardless of solar irradiation, is a significant benefit. The experimental examination of a hybrid hydrogen reactor for producing clean hydrogen is described. The experimental testing is conducted on two processes at three operating temperatures (25 °C, 40 °C, and 55 °C). Processes 1 and 2 are evaluated under two distinct illumination conditions: low (400 W/m2) and high (800 W/m2). The photocurrent production was determined to be 1.1 mA/cm2 under 800 W/m2 after conducting electrochemical experiments. The active electrode area of 49.2 cm2 of the hybrid system demonstrated an exergy efficiency of 3.74 % and an energy efficiency of 3.58 % at an operating temperature of 55 °C, respectively. The Cu2O photocathode achieved 0.78 % solar-to-hydrogen (STH) efficiency at 800 W/m2 and 55 °C, maintaining stability for 88 % of an hour
Period-3 Orbits of Sequential Dynamical Systems and Their Relationship to Error-Correcting Codes over Finite Fields
No full textA sequential dynamical system consists of the following data; a finite graph Y with vertex set v1,& mldr;,vn\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document}, a state set, local update functions, and an update ordering sigma\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document}. We study period-3 orbits of SDSs on the complete graph Kn\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document} with identical local functions. We prove that the maximum number theta n+1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document} of 3-cycles in the phase space equals A3(n,4)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document}, the largest size of a ternary code of length n with minimum Hamming distance at least 4. Our approach reduces the problem to a clique number computation in an explicit graph and yields a direct correspondence with optimal ternary (n, 4)-codes. We also give field-agnostic necessary conditions for prime period-p orbits and discuss extensions over Fp\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document}
Sustainable geopolymer composites incorporating waste volcanic tuff and recycled geopolymer concrete powder as base materials
No full textMicrofluidic-based electrochemical sensing platforms: From classical to advanced platforms for environmental monitoring and clinical diagnostics
No full textMicrofluidic sensing platforms have emerged as essential tools for addressing global needs across various sectors, including environmental monitoring and clinical diagnostics. These applications require devices with selective, sensitive, and portable capabilities that offer multifunctionality. This review focuses on microfluidic devices as an effective tool for environmental and clinical applications. We present the evolution of these platforms, examining their transition from classical to innovative designs and their critical roles in enabling precise measurements. Particular attention is given to various patterns featuring operational units, such as integrated valving systems for controlling fluid flow, reagent storage units, separation or delay zones, and detection units. In addition, the utilization of innovative materials, transitioning from polydimethylsiloxane-based devices to transparent film-based alternatives to overcome the limitations of traditional microfluidic systems, is covered. Here, heavy metals, pesticides, microorganisms, nutrients, polyfluoroalkyl substances, and gases are presented as target analytes for environmental analysis, whereas analyses of nucleic acids, proteins, antigens, and antibiotics are demonstrated for clinical diagnostics. Future perspectives and challenges in advancing microfluidic-based sensing platforms are also discussed
Hybrid meta-heuristic and non-dominated Sorting based optimization for DG and FCL placement considering long-term economic profitability
No full textThe increase in global electricity demand has revealed the limitations of traditional centralized power generation, such as transmission losses, degraded power quality and protection issues. Consequently, DG units have been increasingly integrated into power systems to mitigate these issues. However, higher DG penetration increases fault current levels, potentially exceeding the circuit breaker limits. This may lead to significant economic losses due to equipment damage during short-circuit faults. Therefore, to ensure both system reliability and economic viability, the placement and sizing FCLs must be performed alongside DG optimization. In this study, a multi-objective optimization algorithm is proposed to simultaneously optimize DG and FCL units. The proposed algorithm is validated on IEEE 118-Bus test system using PSO, GA, and GWO. The proposed single-objective optimization achieved 26 % reduction in total power losses and successfully limited fault currents below 25 kA circuit-breaker threshold. In the multi-objective cases, algorithms provide Pareto-optimal solutions spanning 27-29 % variation in power losses, 200-290 % range in FCL costs, and over 3900 % diversity in economic profit, demonstrating the trade-off between technical improvement and economic profitability. The results highlight the importance of a balanced optimization perspective in DG and FCL planning for both economic performance and system reliability
Mediating Role of Self-Efficacy in the Effect of Cognitive Flexibility on Academic Motivation
No full textMiddle school students are subject to considerable stress due to both adolescence and national high school entrance exam preparation in Turkiye. In this context, cognitive flexibility exerts a significant influence on both self-efficacy and academic motivation. This study examines the mediating role of self-efficacy in the relationship between cognitive flexibility and academic motivation. In this correlational study, a sample of 480 middle school students from Istanbul was selected using multistage sampling techniques. The mediation analyses revealed that cognitive flexibility significantly predicts academic, social, and emotional self-efficacy and all subdimensions of academic motivation. Notably, academic self-efficacy exhibits a full or partial mediation effect in the relationship between cognitive flexibility and all subdimensions of academic motivation. Emotional self-efficacy demonstrates partial mediation only in predicting identified regulation and amotivation. The present study is exploratory; consequently, it is anticipated that the results will provide a foundation for subsequent confirmatory studies
π-Conjugated fluorenyl-based phthalocyanines: Synthesis, photophysical, photochemical properties, and biological evaluation
No full textIn the current study, a new phthalonitrile derivative, 4-((9,9-bis(5-hydroxypentyl)-9H-fluoren-2-yl)ethynyl)phthalonitrile (4), was successfully synthesized. Fluorene units were introduced to improve solubility, expand π-conjugation, and tailor photophysical and photochemical properties relevant to PDT and biological applications. Dialkyl-substituted fluorene groups were incorporated into peripherally tetra-substituted zinc (ZnPc) and indium (InPc) phthalocyanines via an acetylene bridge. The fluorescence characteristics and singlet oxygen generation abilities of zinc (5) and indium phthalocyanines (6) were thoroughly examined. To the best of our knowledge, this is the first study to investigate the biological properties of bis(hydroxypentyl)-substituted fluorene-based phthalocyanines across multiple biological parameters. Both, ZnPc (5) and InPc (6) exhibited notable antioxidant, antidiabetic, and DNA cleavage activities. In antimicrobial tests, Enterococcus faecalis, Enterococcus hirae were found to be the most sensitive microorganisms for both compounds, with minimum inhibitory concentrations (MICs) of 8 mg/L. The antibiofilm activities of ZnPc (5) against Pseudomonas aeruginosa and Staphylococcus aureus were 73.1 % and 79.2 %, respectively, while those of InPc (6) were 65.1 % and 68.9 %, respectively. Additionally, ZnPc (5) and InPc (6) showed a concentration-dependent increase in the inhibition of Escherichia coli cell viability, reaching 89.9 % and 97.5 % at 15 mg/L, respectively. In the tests, an increase in antimicrobial and antibiofilm activities was observed under photodynamic antimicrobial therapy (PADT). The most effective MIC value (2 mg/L) was obtained against Enterococcus hirae under PADT conditions. Upon light irradiation, the antibiofilm inhibition rates of ZnPc (5) increased to 94.7 % for Pseudomonas aeruginosa and 91.6 % for Staphylococcus aureus, while InPc (6) exhibited 86.1 % and 86.2 % inhibition against the same pathogens. These results highlight the promising potential of ZnPc (5) and InPc (6) for biomedical applications, particularly in photodynamic therapy and antimicrobial treatments
Autonomous and Autogenous Self-Healing of Freeze-Thaw Cracks of Geopolymer Concrete Containing Colemanite/Red Mud
No full textThis study investigated autonomous and autogenous healing of metakaolin-based geopolymer concrete exposed to the freeze-thaw cycles. Sporosarcina pasteurii was used as a healing agent in the healing process. Samples with and without the S. pasteurii bacteria were produced and cured at 20°C±2°C for 28 days. Subsequently, these samples were exposed to freeze-thaw cycles. Then, the solutions with bacteria and bacteria-free medium were injected into the cracks. After the healing procedure, the ultrasonic pulse velocity, splitting tensile strength, mass change, capillary water absorption, and microstructure experiments were carried out on the samples. The results showed that after the autonomous and autogenous healing, the splitting tensile strength of samples containing bacteria was found to be up to 10.9% greater compared to samples without bacteria. Also, the highest ultrasonic pulse velocity and splitting tensile strength values were obtained from autogenous self-healing samples. Also, the microcomputed tomography found that the bacteria-based healing could heal 91.3% of the total porosity of the sample
Stability of single - layer cube armoured roundheads under wind and swell waves
No full textThis study investigates the stability of single-layer cube-armored breakwater roundheads under varying wave conditions, focusing on the influence of wave steepness, packing density, and cube material density. Experiments were conducted to assess the impact of different packing arrangements (62 % and 69 %) and unit weights (24 kN/m3 and 31.5 kN/m3) on the movement and displacement behavior of armor units. Wind and swell wave conditions were analyzed to evaluate sector-specific behavior across the roundhead. The results reveal that wave steepness plays a critical role in damage initiation, with wind waves causing earlier and more significant movement in the frontal sectors, while swell waves lead to delayed but widespread displacements toward the rear sectors due to enhanced diffraction effects. The roundhead exhibited non-uniform damage distribution, particularly in the second (45°–90°) and third (90°–135°) sectors, which emphasizes the importance of a sector-specific analysis in the design process. Furthermore, this study showed that packing density significantly influences the stability, with higher packing densities providing improved stability, irrespective of the block material density. High density (HD) cubes exhibited less movement compared to normal density cubes, highlighting the importance of geometric arrangement and lateral resistance in ensuring stability. Furthermore, a new formula has been derived based on the experimental data for the one - layer placement of normal density (ND) cubes. Overall, the findings underscore the need for a detailed sector-specific analyses in the design and evaluation of breakwater roundheads to enhance stability and resilience under varying wave conditions
A rare case of LORICRIN gene c.684dup mutation associated with Vohwinkel syndrome in a Turkish patient, in silico analysis and literature review
No full textBackground: Vohwinkel Syndrome (VS) is a rare autosomal dominant skin disorder with two main mutation types: the classic form caused by GJB2 gene mutations and loricrin keratoderma (LK) linked to LOR gene mutations. LK typically lacks hearing loss and often presents at birth as collodion baby syndrome. Methods: A 7-year-old male proband presenting with congenital thickening of the palms and soles was admitted to Başakşehir Çam and Sakura City Hospital. Whole-exome sequencing was performed from a whole blood sample using the MGI-400 platform, and common or benign mutations were excluded. Segregation analysis confirmed a pathogenic LOR mutation. Wild-type and mutant loricrin structures were modeled using I-TASSER and refined with ModRefiner. Protein interactions were analyzed via STRING, and docking with TGase 3 was performed using HDOCK. Structural visualization was completed using UCSF Chimera. Results: A specific LOR mutation [NM_000427.3 c.684dup p.(Ser229ValfsTer107)] was identified, associated with palmoplantar keratoderma, ichthyosis-like plaques on the elbows and knees, anhidrosis, and absence of dental abnormalities, consistent with typical loricrin keratoderma (LK) cases. In silico analysis revealed that wild-type loricrin binds transglutaminase 3 (Tgase 3) with a lower score, and serine interactions present in normal loricrin were absent in the mutant form. Frameshift mutations also reduced glycine motifs critical for epidermal protein organization and skin flexibility. Conclusion: Genetic testing is essential for accurate diagnosis and differentiation of LK from other VS types. This case highlights the importance of genetic screening for early diagnosis and improved management, ultimately enhancing patient care in rare populations