Possible power increase in a natural circulation Soluble-Boron-Free Small Modular Reactor using the Truly Optimized PWR lattice

wijaya steven,NGUYENXUANHA,김용희 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.1

In this study, impacts of an enhanced-moderation Fuel Assembly (FA) named Truly Optimized PWR (TOP) lattice, which is modified based on the standard 17 17 PWR FA, are investigated in a natural circulation Soluble-Boron-Free (SBF) Small Modular Reactor (SMR). Two different TOP lattice designs are considered for the analysis; one is with 1.26 cm pin pitch and 0.38 cm fuel pellet radius, and the other is with 1.40 cm pin pitch and 0.41 cm fuel pellet radius. The NuScale core design is utilized as the base model and assumed to be successfully converted to an SBF core. The analysis is performed following the primary coolant circulation loop, and the reactor is modelled as a single channel for thermal-hydraulic analyses. It is assumed that the ratio of the core pressure drop to the total system pressure drop is around 0.3. The results showed that the reactor power could be increased by 2.5% and 9.8% utilizing 1.26/0.38 cm and 1.40/0.41 cm TOP designs, respectively, under the identical coolant inlet and outlet temperatures as the constraints.

Two Verification Phases in Multimedia Authoring Modeling

Wijaya, Marvin Chandra,Maksom, Zulisman,Abdullah, Muhammad Haziq Lim The Korea Institute of Information and Commucation 2021 Journal of information and communication convergen Vol.19 No.1

Multimedia Authoring Tool is a tool for creating multimedia presentations. With this tool, a user can produce playable multimedia documents. A Multimedia Authoring Tool requires input in the form of a spatial layout and a temporal layout. Users can make many mistakes in creating multimedia presentations and verification is required in the Multimedia Authoring process in order to produce multimedia documents. In this study, two verification phases are proposed: Time Computation and Spatiotemporal Conflict Verification. In the experiment conducted for this study, two kinds of verification were carried out: The use of single-phase verification and the use of double-phase verifications. By using these two types of verification, it became easier to successfully detect errors in the spatial and temporal layouts, and the types of verification have also been successful in increasing the success of error detection.

Metal nanocrystal-based sensing platform for the quantification of water in water-ethanol mixtures

Wijaya, Yosia Nico,Kim, Jinwoo,Hur, Seung Hyun,Park, Sung Hwan,Kim, Mun Ho Elsevier 2018 Sensors and actuators. B Chemical Vol.263 No.-

<P><B>Abstract</B></P> <P>Triangular silver (Ag) nanoplates with sharp corners exhibit fascinating optical properties, but their triangular shapes make them thermodynamically unstable. In the current work, we used this intrinsic instability as the basis for a novel sensing platform for the quantification of water in water-ethanol mixtures. Specifically, we designed a system that uses the color and spectral changes associated with the spontaneous rounding of the sharp corners of triangular Ag nanoplates exposed to bromide ions (Br<SUP>−</SUP>) to quantify the water fraction in water-ethanol mixtures. The rate of change of the color and spectral features of a water-ethanol mixture containing Ag nanoplates resulting from the introduction of KBr was found to be strongly correlated with the volume fraction of water in the mixture. This relationship, which was attributed to the dependence of the solubility of KBr on the volume fraction of water in water-ethanol mixtures, allowed the quantification of water in water-ethanol mixtures having any water volume fraction (from 0 to 1.0). The proposed colorimetric sensing platform exhibited reliable sensing results in two real products containing water and ethanol (an alcoholic beverage and an ethanol-based hand sanitizer). It was also successfully applied to determining the relative amount of water in water-isopropyl alcohol mixtures, suggesting that it can be applied to mixtures of water and other alcohols. The present findings suggest that the proposed nanocrystal-based sensing platform holds great potential for use as a point-of-care analytical tool for the quantification of water in the fine chemical, pharmaceutical, and food and beverage industries.</P> <P><B>Highlights</B></P> <P> <UL> <LI> New platform for water sensing in water-ethanol mixtures is proposed. </LI> <LI> New sensing platform can operate for the mixtures having any water concentration. </LI> <LI> Mixtures of water and other alcohols can be applied to the sensing platform. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Effect of Sulfation on Physicochemical Properties of ZrO₂ and TiO₂ Nanoparticles

Wijaya, Karna,Pratika, Remi Ayu,Fitri, Edhita Rahmawati,Prabani, Prisnu Fadilah,Candrasasi, Yufinta,Saputri, Wahyu Dita,Mulijani, Sri,Patah, Aep,Wibowo, Arief Cahyo Materials Research Society of Korea 2022 한국재료학회지 Vol.32 No.3

Effect of sulfation processes on the physicochemical properties of ZrO₂ and TiO₂ nanoparticles were thoroughly investigated. SO₄/ZrO₂ and SO₄/TiO₂ catalysts were synthesized to identify the acidity character of each. The wet impregnation method of ZrO₂ and TiO₂ nanoparticles was employed using H2SO₄ with various concentrations of 0.5, 0.75, and 1 M, followed by calcination at 400, 500, and 600 ℃ to obtain optimum conditions of the catalyst synthesis process. The highest total acidity was found when using 1 M SO₄/ZrO₂-500 and 1 M SO₄/TiO₂-500 catalysts, with total acidity values of 2.642 and 6.920 mmol/g, respectively. Sulfation increases titania particles via agglomeration. In contrast, sulfation did not practically change the size of zirconia particles. The sulfation process causes color of both catalyst particles to brighten due to the presence of sulfate. There was a decrease in surface area and pore volume of catalysts after sulfation; the materials' mesoporous structural properties were confirmed. The 1 M SO₄/ZrO₂ and 1 M SO₄/TiO₂ catalysts calcined at 500 ℃ are the best candidate heterogeneous acid catalysts synthesized in thus work.

Multi-batch core design study for innovative small modular reactor based on centrally-shielded burnable absorber

wijaya steven,Nguyen Xuan Ha,정윤석,김용희 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.3

Various core designs with multi-batch fuel management (FM) are proposed and optimized for an innovative small modular reactor (iSMR), focusing on enhancing the inherent safety and neutronic performance. To achieve soluble-boron-free (SBF) operation, cylindrical centrally-shielded burnable absorbers (CSBAs) are utilized, reducing the burnup reactivity swing in both two- and three-batch FMs. All 69 fuel assemblies (FAs) are loaded with 2-cylindrical CSBA. Furthermore, the neutron economy is improved by deploying a truly-optimized PWR (TOP) lattice with a smaller fuel radius, optimized for neutron moderation under the SBF condition. The fuel shuffling and CSBA loading patterns are proposed for both 2- and 3-batch FM with the aim to lower the core leakage and achieve favorable power profiles. Numerical results show that both FM configurations achieve a small reactivity swing of about 1000 pcm and the power distributions are within the design criteria. The average discharge burnup in the two-batch core is comparable to three-batch commercial PWR like APR-1400. The proposed checker-board CR pattern with extended fingers effectively assures cold shutdown in the two-batch FM scenario, while in the three-batch FM, three N-1 scenarios are failed. The whole evaluation process is conducted using Monte Carlo Serpent 2 code in conjunction with ENDF/B-VII.1 nuclear library.

Antiplatelet Aggregation Potencies of some Allium spp. Grown in Indonesia

Wijaya, C. Hanny,Muchtadi, Deddy,Lalel, Herianus J.,Zakaria, Fransiska,Koswara, Sutrisno The Korean Society of Pharmacognosy 1996 Natural Product Sciences Vol.2 No.1

Several species and varieties of Allium spp. grown in Indonesia were screened for their in vitro antiplatelet aggregation activities. The extracts were also analyzed by GC for their volatile sulfur-containing compounds, and measured for their Volatile Reducing Substances (VRS) contents. Antiplatelet aggregation potencies of Allium spp. were varied among the species and varieties studied. Garlic extracts showed the greatest ability to inhibit platelet aggregation followed by extract of shallot, chive, yellow onion, and green onion. The 'Jawi' and 'local Padang' variety of garlic showed high activities with $IC_{50}$ values of 9.1 and $9.8\;{\mu}g/ml$, respectively. The local Kupang variety of shallot showed the highest antiplatelet activity among the shallot varieties evaluated, with an $IC_{50}$ value of $111\;{\mu}g/ml$. Antiplatelet aggregation activities of Allium extracts showed a positive correlation with the level of volatile compounds.

A systematic study of triangular silver nanoplates: one-pot green synthesis, chemical stability, and sensing application

Wijaya, Y.,Kim, J.,Choi, W.,Park, S.,Kim, M. Royal Society of Chemistry 2017 Nanoscale Vol.9 No.32

Triangular Silver Nanoplates: Green Synthesis and Sensing Application

Yosia Wijaya,김진우,김문호 한국고분자학회 2018 한국고분자학회 학술대회 연구논문 초록집 Vol.43 No.1

The Effects of Cognitive Grammar-grounded Instruction and Formal- Traditional Grammar Instruction on Learning Simple Past and Past Perfect

David Wijaya,Anderson Hidarto 아시아테플 2018 The Journal of Asia TEFL Vol.15 No.4

The English tense and aspect system has long posed great difficulty to second language (L2) learners due to their underlying complex concepts. This difficulty is compounded by oversimplified grammatical descriptions found in many ELT textbooks. Cognitive Grammar (CG) offers comprehensive accounts of tenses that could be useful for learners. This paper reports a quasiexperimental study investigating the differential effects of CG-informed form-focused instruction and formalist-traditional form-focused instruction on the acquisition of two English tenses, namely the simple past and the past perfect. Secondary school EFL learners (final pool: N = 36) were assigned to two groups (CG and Traditional). Learners in the CG group were exposed to CG-grounded grammatical descriptions of the tenses while learners in the traditional group received traditional accounts. Both groups performed awareness-raising tasks to enhance learning. Data were gathered from the learners’ performance in a cloze narrative task. Results from an immediate post-test revealed that CG-based descriptions helped learners improve significantly and outperform learners in the traditional group. These findings indicate the superiority of a CG approach to a formalist approach to teaching the tenses and lend support to the applicability and efficacy of CG-grounded form-focused instruction in the classroom.

Nutritional Status of Indonesian Children in Low-Income Households with Fathers that Smoke

Maria Wijaya-Erhardt 질병관리본부 2019 Osong Public Health and Research Persptectives Vol.10 No.2

Objectives: This study compared the nutritional status of children in low-income households in Indonesia whose fathers were either cigarette smokers or non-smokers. Methods: A cross sectional study of 482 children aged 2-6 years was conducted, stratified by whether the fathers were non-smoking (n = 138) or smoking (n = 340). Mothers and smoking fathers were interviewed about socioeconomic status and cigarette expenditure, respectively. The nutritional status of children was defined by weight-for-age, height-for-age and weight-for-height. Results: Both groups had similar income. Households with a father that smoked, spent 16.6% of their income on cigarettes. Children whose fathers did not smoke had higher height-for-age (-1.99 vs. -2.25 Z-score, p = 0.02) than children whose fathers smoked. Weight-for-age in children with fathers that did not smoke was greater (-1.49 vs. -1.64 Z-score) but not statistically significantly different to those children with fathers that smoked, nor was child weight-for-height (-0.46 vs. -0.45 Z-score). The prevalence of stunted growth was higher in the children with a father that smoked compared with those that had a father did not smoke (62.2 vs. 49.6%, p = 0.07, respectively). There were 28.3% of children underweight in homes where the fathers did not smoke, and 35.6% in households where the father smoked (p = 0.11). Wasting was observed in 4.4% children where fathers did not smoke and 4.7% where fathers did smoke. Conclusion: With similar income constraints, the degree of height growth faltering was less in children whose fathers did not smoke, compared to those whose fathers did smoke.