• Progress in Superconductivity and Cryogenics
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• v.25 no.2
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• pp.5-9
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• 2023

The effect of La_0.7Sr_0.3MnO₃ (LSMO) addition on the superconducting property of Bi_1.6Pb_0.4Sr₂Ca₂Cu₃O_10+δ ((Bi, Pb)-2223) polycrystalline samples was studied. LSMO (0.3 wt.% to 2.0 wt.%) added (Bi, Pb)-2223 samples were prepared by using a solid-state reaction method. The XRD analyses show that as the LSMO addition increases, the volume fraction of the Bi-2223 phase is gradually decreased. The critical temperature (T_c) exhibits a gradual decrease with a single transition as the LSMO amount increases up to 1.0 wt.%, but a further addition of LSMO induces an abrupt decrease of T_c with a dual transition. The analyses on the local structure of the CuO₂ plane from the X-ray absorption fine structure (EXAFS) measurements showed that for the samples with low concentration of LSMO up to 1.0 wt.%, the Cu-O bond length and the CuO₂ plane ordering do not degrade from the values of pure (Bi, Pb)-2223, while they get worsen with a further increase of LSMO addition. These results open up the possibility of LSMO as artificial pinning centers of the (Bi, Pb)-2223 system for power application.

• Current Optics and Photonics
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• v.7 no.6
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• pp.721-731
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• 2023

This paper studies various roughness parameters, besides waviness, texture, and nonlinear parameters of Bismarck brown Y (BBY)-doped Poly(methyl methacrylate) (PMMA) films based on the computed values of optical limiting (OL) threshold power and nonlinear refractive index. The films' morphology, grain size, and absorption spectra were investigated using atomic force microscopy in conjunction with ultraviolet-visible (UV-Vis) spectrophotometer. The particle size of the films ranged between 4.11-4.51 mm and polymer films showed good homogeneity and medium roughness, ranging from 1.11-4.58 mm. A polymer film's third-order nonlinear optical features were carried out using the Z-scan methodology. The measurements were obtained by a continuous wave produced from a solid-state laser with a 532 nm wavelength. According to the results, BBY has a nonlinear refractive index of 10^-6 cm²/W that is significantly negative and nonlinear. The optical limiting thresholds are roughly 10.29, 13.52, and 18.71 mW, respectively. The shift of nonlinear optical features with the film's concentration was found throughout the experiment Additionally, we found that the polymer samples have outstanding capabilities for restricting the amount of optical power that may be transmitted through them. We propose that these films have the potential to be used in a wide variety of optoelectronic applications, including optical photodetectors and optical switching.

• Animal Bioscience
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• v.37 no.6
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• pp.1031-1040
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• 2024

Objective: This study aimed to evaluate the effect of feeding milk replacer (MR) with varying levels of lactose and the increased supply of total solids (from 750 to 960 g/d) on performance, blood metabolites, and health of Holstein male calves during the preweaning period. Methods: Forty newborn Holstein calves (10 per treatment) were blocked according to birth weight and date of birth and distributed in a randomized block design to different liquid diets: Whole milk powder (WMP) diluted to 125 g/L solids; MR with 48% lactose (48L), diluted to 125 g/L solids; MR with 53% lactose (53L), diluted to 125 g/L solids; 53L MR corrected to 160 g/L solids (16TS) by the inclusion of a solid corrector. Calves were individually housed in wood hutches, fed 6 L/d of the liquid diet, and had free water and starter concentrate access. The study lasted 56 days. Results: Liquid diet intake was higher for calves fed 16TS than for other treatments. Calves fed 16TS presented higher protein and fat intake, followed by those fed WMP and the 48L or 53L MRs. Lactose intake was higher for 16TS-fed calves, followed by 53L, 48L, and WMP-fed calves. Starter and total dry matter intake did not differ among liquid diets. The average daily gain was higher for 16TS than 48L-fed calves, with the other treatments being intermediary. The lowest feed efficiency was observed for calves fed 48L. No effects on health were observed, as well as on selected blood metabolites, except for albumin concentration, which was higher for calves fed 16TS and WMP. Conclusion: Higher total solids content (160 g/L) in MR increases nutrient intake and consequently improves the performance of dairy calves. Feeding MRs with levels of lactose up to 53% of the DM had no deleterious effect on the performance or health of the calves.

• Advances in nano research
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• v.16 no.4
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• pp.341-352
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• 2024

This study investigates the heat and mass transfer characteristics of a MoS₂ nanoparticle suspension in ethylene glycol over a porous stretching sheet. MoS₂ nanoparticles are known for their exceptional thermal and chemical stability which makes it convenient for enhancing the energy and mass transport properties of base fluids. Ethylene glycol, a common coolant in various industrial applications is utilized as the suspending medium due to its superior heat transfer properties. The effects of variable thermal conductivity, variable mass diffusivity, thermal radiation and thermophoresis which are crucial parameters in affecting the transport phenomena of nanofluids are taken into consideration. The governing partial differential equations representing the conservation of momentum, energy, and concentration are reduced to a set of nonlinear ordinary differential equations using appropriate similarity transformations. R software and MATLAB-bvp5c are used to compute the solutions. The impact of key parameters, including the nanoparticle volume fraction, magnetic field, Prandtl number, and thermophoresis parameter on the flow, heat and mass transfer rates is systematically examined. The study reveals that the presence of MoS₂ nanoparticles curbs the friction between the fluid and the solid boundary. Moreover, the variable thermal conductivity controls the rate of heat transfer and variable mass diffusivity regulates the rate of mass transfer. The numerical and statistical results computed are mutually justified via tables. The results obtained from this investigation provide valuable insights into the design and optimization of systems involving nanofluid-based heat and mass transfer processes, such as solar collectors, chemical reactors, and heat exchangers. Furthermore, the findings contribute to a deeper understanding of stretching sheet systems, such as in manufacturing processes involving continuous casting or polymer film production. The incorporation of MoS₂-C₂H₆O₂ nanofluids can potentially optimize temperature distribution and fluid dynamics.

• Food Science and Preservation
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• v.30 no.4
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• pp.549-561
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• 2023

Recently, consumers have gained an interest in natural and minimally processed foods, inciting the food industry to consider using of natural products as preservatives. Strawberries are a widely consumed fruit but are also highly perishable. Therefore, in this study, the physicochemical properties of strawberries (Fragaria×ananassa) were evaluated after a 12-h treatment with lemon essential oil (Citrus×limon) or cinnamon essential oil (Cinnamomum cassia) vapor during storage at 22℃ for 4 days in an accelerated shelf-life study and 4℃ for 18 days in a validation study. Weight loss was blunted in fruit treated with oil vapor during the first days of storage (p<0.05). Lemon essential oil delayed fruit darkening (p<0.05) but reduced the firmness of strawberries (p<0.05). Strawberries treated with cinnamon essential oil had a higher concentration of reducing sugars (p<0.05), and a decrease of 16.7% visible decay, although the difference was insignificant. Oil vapor treatment did not alter the pH, organic acid content, or soluble solid content during storage compared to the control. Since lemon and cinnamon essential oils have well-documented antimicrobial properties, they may be suitable for the natural preservation of fruit. This study provides new information on using essential oil vapor treatment to preserve fruits, and potentially decrease fruit loss and waste.

• Nuclear Engineering and Technology
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• v.56 no.1
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• pp.147-159
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• 2024

Plutonium-238 has always been considered as the one of the promising radioisotopes for space nuclear power supply, which has long half-life, low radiation protection level, high power density, and stable fuel form at high temperatures. The industrial-scale production of ²³⁸Pu mainly depends on irradiating solid ²³⁷NpO₂ target in high flux reactors, however the production process faces problems such as large fission loss and high requirements for product quality control. In this paper, a conceptual design study of producing ²³⁸Pu in a multi-purpose high flux reactor was evaluated and analyzed, which includes a sensitivity analysis on ²³⁸Pu production and a further study on the irradiation scheme. It demonstrated that the target structure and its location in the reactor, as well as the operation scheme has an impact on ²³⁸Pu amount and product quality. Furthermore, the production efficiency could be improved by optimizing target material concentration, target locations in the core and reflector. This work provides technical support for irradiation production of ²³⁸Pu in high flux reactors.

• Food Science of Animal Resources
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• v.44 no.4
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• pp.790-804
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• 2024

This study compared the physicochemical properties of edible insect oils from silkworm (Bombyx mori) pupa (SP), sago palm weevil (Rhynchophorus ferrugineus) larva (PW), and bamboo caterpillar (Omphisa fuscidentalis; BC) to oils from chicken skin (CK), beef back fat (BF), pork back fat (PF), salmon belly (SB), sea bass belly (BB), coconut (C), and peanut (P). The fatty acid profiles and thermal behaviors (crystallization and melting) of the extracted oils were evaluated. PW and BC oils had more saturated fatty acids (SFAs) than CK, PF, SB, BB, and P oils. SP oil had equivalent SFA content to CK and BB oils. Insect oils exhibited similar monounsaturated fatty acid concentrations in all samples, except C oils. PW and BC oils exhibited a higher content of palmitoleic acid than the other oils. SP oils contained polyunsaturated fatty acids similar to those in SB and BB oils, which were higher than those in PW, BC, CK, BF, and PF oils. SP oil also exhibited the highest concentration of α-linolenic acid (C18:3 n-3). Arachidonic acid (0.01-0.02 g/100 g) in all insect oils was lower level compared to CK, BF, PF, SB, and BB oils. SP oil (0.03 g/100 g) exhibited a slightly higher level of eicosapentaenoic acid compared to PW (0.01 g/100 g) and BC (0.01 g/100 g) oils. The insect oils were liquid at ambient temperature, solid below -15℃, and required less energy (∆H_m-max) for melting than other samples. This study indicated that insects, particularly SP, could serve as an alternative source of fat to meet its growing demand.

• Journal of Korean Society of Water and Wastewater
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• v.37 no.5
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• pp.253-259
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• 2023

Bioreactors are devices used by sewage treatment plants to process sewage and which produce active sludge, and sediments separated by solid-liquid are treated in anaerobic digestion tanks. In anaerobic digestion tanks, the volume of active sludge deposits is reduced and biogas is produced. After dehydrating the digestive sludge generated after anaerobic digestion, anaerobic digested wastewater, which features a high concentration of organic matters, is generated. In this study, the decomposition of organic carbon and nitrogen was studied by advanced oxidation process. Ozone-microbubble flotation process was used for oxidation pretreatment. During ozonation, the TOC decreased by 11.6%. After ozone treatment, the TOC decreased and the removal rate reached 80.4% as a result of the Ultra Violet-Advanced Oxidation Process (UV-AOP). The results with regard to organic substances before and after treatment differed depending on the organic carbon index, such as CODMn, CODCr, and TOC. Those indexes did not change significantly in ozone treatment, but decreased significantly after the UV-AOP process as the linkage treatment, and were removed by up to 39.1%, 15.2%, and 80.4%, respectively. It was confirmed that biodegradability was improved according to the ratio of CODMn to TOC. As for the nitrogen component, the ammonia nitrogen component showed a level of 3.2×10² mg/L or more, and the content was maintained at 80% even after treatment. Since most of the contaminants are removed from the treated water and its transparency is high, this water can be utilized as a resource that contains high concentrations of nitrogen.

• Journal of Microbiology and Biotechnology
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• v.34 no.5
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• pp.1135-1145
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• 2024

When cells are exposed to freezing temperatures, high concentrations of cryoprotective agents (CPA) prevent ice crystal formation, thus enhancing cell survival. However, high concentrations of CPAs can also cause cell toxicity. Exopolysaccharides (EPSs) from polar marine environments exhibit lower toxicity and display effects similar to traditional CPA. In this study, we sought to address these issues by i) selecting strains that produce EPS with novel cryoprotective activity, and ii) optimizing culture conditions for EPS production. Sixty-six bacteria producing mucous substances were isolated from the Ross Sea (Antarctic Ocean) using solid marine agar plates. Among them, Pseudoalteromonas sp. RosPo-2 was ultimately selected based on the rheological properties of the produced EPS (p-CY02). Cryoprotective activity experiments demonstrated that p-CY02 exhibited significantly cryoprotective activity at a concentration of 0.8% (w/v) on mammalian cells (HaCaT). This activity was further improved when combined with various concentrations of dimethyl sulfoxide (DMSO) compared to using DMSO alone. Moreover, the survival rate of HaCaT cells treated with 5% (v/v) DMSO and 0.8% (w/v) p-CY02 was measured at 87.9 ± 2.8% after freezing treatment. This suggests that p-CY02 may be developed as a more effective, less toxic, and novel non-permeating CPA. To enhance the production of EPS with cryoprotective activity, Response Surface Methodology (RSM) was implemented, resulting in a 1.64-fold increase in production of EPS with cryoprotective activity.

• Journal of Radiation Industry
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• v.17 no.2
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• pp.183-190
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• 2023

The global problem of handling radioactive materials is facing limitations. Eco-friendly bioremediation methods using microorganisms are being studied. This study was conducted to screen cesium-resistant microbial strains. M1 strain was selected from the soil sample by enriched culture in R2A medium containing 100 mM CsCl. In liquid medium containing above 40 mM of CsCl, the growth of M1 was inhibited in a concentration-dependent manner. Otherwise, M1 can survive up to 80mM CsCl in solid medium although the growth rate was slow and colony size was small. M1 strain was genetically identified as a strain of the genus Acinetobacter through 16S rRNA sequencing, and radiation resistance (D10 value) of M1 was found to be 0.307 kGy. These results showed that M1 strain is highly resistant to cesium and can grow in radiation environment. It was considered that M1 strain is useful in the field of biological decontamination of cesium.