This work reports on the simulated neutron and self-emitted gamma attenuation of ultra-high-molecular-weight polyethylene (UHMWPE) composites containing varying Sm2O3 contents in the range 0–50 wt.%, using a simulation code, namely MCNP-PHITS. The neutron energy investigated was 0.025 eV (thermal neutrons), and the gamma energies were 0.334, 0.712, and 0.737 MeV. The results indicated that the abilities to attenuate thermal neutrons and gamma rays were noticeably enhanced with the addition of Sm2O3, as seen by the increases in µm and µ, and the decrease in HVL. By comparing the simulated neutron-shielding results from this work with those from a commercial 5%-borated PE, the recommended Sm2O3 content that attenuated thermal neutrons with equal efficiency to the commercial product was 11–13 wt.%. Furthermore, to practically improve surface compatibility between Sm2O3 and the UHMWPE matrix and, subsequently, the overall wear/mechanical properties of the composites, a silane coupling agent (KBE903) was used to treat the surfaces of Sm2O3 particles prior to the preparation of the Sm2O3/UHMWPE composites. The experimental results showed that the treatment of Sm2O3 particles with 5–10 pph KBE903 led to greater enhancements in the wear resistance and mechanical properties of the 25 wt.% Sm2O3/UHMWPE composites, evidenced by lower specific wear rates and lower coefficients of friction, as well as higher tensile strength, elongation at break, and surface hardness, compared to those without surface treatment and those treated with 20 pph KBE903. In conclusion, the overall results suggested that the addition of Sm2O3 in the UHMWPE composites enhanced abilities to attenuate not only thermal neutrons but also gamma rays emitted after the neutron absorption by Sm, while the silane surface treatment of Sm2O3, using KBE903, considerably improved the processability, wear resistance, and strength of the composites.

Ulva rigida C. Agardh (sea lettuce) is a marine green alga. It grows naturally near shorelines in areas with freshwater influence. It can also be cultivated easily on farms and can be developed into many healthy food products, which bring in revenue for Thailand. It is important to develop an effective way to cultivate the alga. In this research, the molecular biology of sea lettuce using the tufA gene for the identification of Ulva genus and morphological characters at different culturing periods of U. rigida thallus were investigated using a light microscope (LM), a scanning electron microscope (SEM) and a transmission electron microscope (TEM). The results revealed that the U. rigida alga consisted of various cell shapes including elliptic, irregular triangle, irregular quadrilateral, pentagonal and polygonal. The cell size increased with increasing periods of culture. However, when the alga was cultured for 28 days, the cell sizes were smaller than the original cells due to cell division during aging, resulting in an increase in cell numbers. U. rigida had grown rapidly in 14 days which was a relatively short period of cultivation. The results of this study indicate that U. rigida has a potential to be scaled up in pilot and commercial scales. HIGHLIGHTS The molecular analysis of sea lettuce from Phetchaburi Coastal Aquaculture Research and Development Center, Sub District: Bang Kaeo, District: Ban Laem at Phetchaburi Province, Thailand was found to be rigida The morphological and anatomical characters of rigida thalli were studied with light microscope, transmission electron microscope and scanning electron microscope techniques The cell sizes of rigida thalli changed with culturing days. They were the largest at 14 days in the surface view, and at 14 and 21 days in the transverse section GRAPHICAL ABSTRACT

Ulva rigida green seaweed is an abundant biomass consisting of polysaccharides and protein mixtures and a potential bioresource for bioplastic food packaging. This research prepared and characterized novel biodegradable films from Ulva rigida extracts. The water-soluble fraction of Ulva rigida was extracted and prepared into bioplastic films. 1H nuclear magnetic resonance indicated the presence of rhamnose, glucuronic and sulfate polysaccharides, while major amino acid components determined via high-performance liquid chromatography (HPLC) were aspartic acid, glutamic acid, alanine and glycine. Seaweed extracts were formulated with glycerol and triethyl citrate (20% and 30%) and prepared into films. Ulva rigida films showed non-homogeneous microstructures, as determined via scanning electron microscopy, due to immiscible crystalline component mixtures. X-ray diffraction also indicated modified crystalline morphology due to different plasticizers, while infrared spectra suggested interaction between plasticizers and Ulva rigida polymers via hydrogen bonding. The addition of glycerol decreased the glass transition temperature of the films from −36 °C for control films to −62 °C for films with 30% glycerol, indicating better plasticization. Water vapor and oxygen permeability were retained at up to 20% plasticizer content, and further addition of plasticizers increased the water permeability up to 6.5 g·mm/m2·day·KPa, while oxygen permeability decreased below 20 mL·mm/m2·day·atm when blending plasticizers at 30%. Adding glycerol efficiently improved tensile stress and strain by up to 4- and 3-fold, respectively. Glycerol-plasticized Ulva rigida extract films were produced as novel bio-based materials that supported sustainable food packaging.

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Sea lettuce (Ulva rigida) is an underutilized green macroalga. Scant knowledge and understanding exist regarding the optimal processing technologies to maximize seaweed nutrition. Pretreatment of sea lettuce before drying, either by blanching or steaming, induced diverse physical and biological property changes. Greenness increased, while lightness of the-sea lettuce reduced. Both drying processes reduced textural parameters and impacted sea lettuce bioactivity, with increased antioxidant capacity and phenolic compound content. Steaming followed by oven drying at 60 °C for 2.30 h maintained bioactivities during 4 months of storage. Food processing increased the ease of consumption and also maintained the nutritional value of the sea lettuce, thereby promoting the utilization of this seaweed as a beneficial food ingredient.