Comparative Study on the Optical Properties of Sm3+ Doped Glasses with Shell-Based and Commercial Calcium Oxide Modifiers

Sun, 22 Feb 2026 00:00:00 +0700

This study focuses on the optical and basic physical properties of samarium (Sm³⁺)-doped glasses prepared using calcium oxide (CaO) derived from mussel and cockle shells as glass network modifiers, and compares them with commercial CaO. X-ray fluorescence (XRF) analysis showed that the shell-derived CaO possessed high purity, with CaO content exceeding 99% after calcination at 900°C for 5 hours. X-ray diffraction (XRD) results revealed that prior to calcination, the primary phase in the shells was calcium carbonate (CaCO₃), while after heat treatment, the dominant phase transformed into calcium oxide (CaO). This indicates successful thermal decomposition of CaCO₃ and effective phase transition under the given conditions. In terms of optical properties, the shell-derived glass samples exhibited higher emission intensity and longer lifetimes compared to the commercial CaO sample. The density, refractive index, and molar volume values were comparable across all samples, suggesting that the use of shell-derived CaO does not significantly alter the physical properties of the glass. These results demonstrate the potential of shell-derived CaO as a sustainable alternative raw material for the production of luminescent glasses, contributing to environmentally friendly and cost-effective materials development.

Human Fecal Contamination of Toilet Doors and Food Preparation Surfaces in Households with Poor-Quality Sanitation Facilities in Ibule-Soro, Nigeria

Timileyin Olanrewaju, Adewale Olalemi , Jumoke Olaleye — Mon, 23 Mar 2026 00:00:00 +0700

Contaminated surfaces are potential breeding habitats for pathogenic organisms. Toilet doors and food preparation surfaces may serve as fomites in the indirect transmission of pathogens as a result of fecal contamination. This study set out to determine the bacterial communities and levels of enteric bacteria on toilet doors and food preparation surfaces in households with poor-quality toilet facilities in Ibule-Soro, Nigeria. 24 Swab samples from toilet doors and food preparation surfaces were collected from each of the five households over a period of six months within 12 sampling events. The abundance and identity of bacteria in the samples were determined using both culture-based and molecular methods (16S rRNA gene sequencing). Risks factors of fecal contamination were also assessed. Results revealed that the concentration of Escherichia coli ranged from 2.15 to 2.64 log₁₀ CFU/ml) while Salmonella ranged from 1.07 to 2.15 log₁₀CFU/ml. The common bacterial phyla detected were Proteobacteria, Actinobacteria and Firmicutes while Proteobacteria was the most abundant (42.45%) phylum. Risk factors such as toilet facilities, most especially ‘No toilet’ and ‘Manageable access to soap’ exhibited high significant association with the presence and load of Enterobacter, Klebsiella, Proteus. Toilet doors had higher frequency of occurrence of enteric bacteria than food preparation surfaces but food preparation surfaces had higher load of enteric bacteria than toilet doors. Isolates from toilet doors had higher normal distribution pattern than isolates from food preparation surfaces. In order to protect human health from infections, the quality of the toilet facilities in the households must be improved, adequate hygiene practices must be encouraged and food preparation surfaces must be cleaned and sanitized regularly.

Suan Sunandha Science and Technology Journal

Comparative Study on the Optical Properties of Sm3+ Doped Glasses with Shell-Based and Commercial Calcium Oxide Modifiers

Human Fecal Contamination of Toilet Doors and Food Preparation Surfaces in Households with Poor-Quality Sanitation Facilities in Ibule-Soro, Nigeria