Atomic Energy Research Articles

LONG-TERM ENERGY DEMAND THROUGH BOTTOM-UP ANALYSIS AND PROJECTION FOR KUWAIT

In this study, an energy demand projection and analysis were conducted for the State of Kuwait, which has an oil-based economy. A bottom-up approach was used to conduct energy demand projection and analysis by utilizing the Model for Energy Demand Analysis (MAED), which is a software package developed by the International Atomic Energy Agency (IAEA). The energy demand projection was conducted until 2050, with 2019 as the base year. The total demand is expected to grow from 210.9 TWh in 2019 to 373.07 TWh in 2050. The industrial sector dominates final energy demand, with a percentage of 45.1% in 2019 and is expected to reach 55.8% by 2050. Reliance on fossil fuels for energy demand will persist with an annual growth rate of 4% throughout the projection period. The electricity demand in the household and service sectors has the highest share of space cooling during the long summer months. Policy implications in response to energy demand consumption patterns are discussed to achieve national sustainable economic growth and environmental requirements. The implementation of rules and regulations to deploy and use equipment and machinery with high energy efficiency ratings will assist in energy savings in the industrial sector. Providing incentives to use building materials with high insulation can significantly reduce the energy demand for space cooling. Setting high-efficiency rating standards for engine specifications for vehicles imported to Kuwait will help reduce the consumption of motor fuels in the transportation sector.

Quantification of natural uranium and its risk evaluation in groundwater of Chikkaballapur district in Karnataka, India.

The present study focused on the distribution of uranium in groundwater samples collected from various sources in the Chikkaballapur district and its associated risk in humans. Seventy-five groundwater samples were collected during pre-monsoon and post-monsoon seasons and were analysed for uranium concentration along with different water quality parameters. The uranium concentration ranged from 0.23 to 285.23µg/L in the pre-monsoon season and from 0.02 to 107.87µg/L in the post-monsoon season. More than 90% of samples, except a few, were under the safe limits of 60µg/L as directed by the Department of Atomic Energy (DAE) of India's Atomic Energy Regulatory Board (AERB). The study analysed physicochemical parameters like pH, total dissolved solids (TDS), nitrate, total hardness, phosphate, sulphate and fluoride in collected water samples. Out of all samples, few samples noted higher values of TDS, nitrate and fluoride. Their correlation along with uranium is detailed in the study. Owing to its slightly elevated content, an evaluation of the radiological and chemical hazards associated with uranium consumption was analysed. When the risk resulting from chemical toxicity was evaluated, relatively few samples had a hazard quotient (HQ) score higher than 1, which suggested that the people were vulnerable to chemical danger. This study also evaluates the dangers of elevated uranium levels in groundwater samples to the general public's health. It also acknowledges the importance of routinely evaluating and treating the drinking water sources in the region.

A Multi-Objective Optimization Design for Enhancing Space Utilization and Minimizing Cutting Time in Nuclear Facility Component Decommissioning

According to the International Atomic Energy Agency’s requirements for the minimization of radioactive waste, nuclear facility components need to be cut into smaller blocks and packaged in waste containers during decommissioning. Therefore, it is important to increase the space utilization (SU) of the cut blocks in the containers while reducing the cutting time (CT). In engineering practice, increasing SU often leads to longer CTs, which poses a great challenge to improve the efficiency of the nuclear decommissioning process. To overcome this challenge and to determine the optimal operational parameters, this paper introduces a multi-objective optimization design method for cutting and packaging nuclear facility components. The goal is to increase SU while concurrently reducing CTs, ultimately minimizing the waste and reducing the decommissioning cost. First, we project the intricate three-dimensional (3D) irregular parts packing problem onto a two-dimensional plane to simplify the complexity inherent in 3D parts packing and to formulate a packing optimization model. Second, we employ the Morris method to perform global sensitivity analysis on critical parameters, including cutting angle, height, component radius, and plate thickness parameters, throughout the cutting process of nuclear facility components. This analysis produces global sensitivity indicators for each parameter, facilitating a precise assessment of the sensitivity values associated with different operational parameters. Finally, we formulate a multi-objective design optimization model for cutting and packing nuclear facility components that yields a series of alternative operating parameter solutions upon solving it. This methodology offers a resolution for the selection of optimal operational parameters in the decommissioning process of nuclear facility components, thereby attaining optimal outcomes in waste disposal and furnishing guidance for subsequent decommissioning activities.

An efficient method to generate near-ideal hollow beams of different shapes for box potential of quantum gases.

Ultracold quantum gases are usually prepared in conservative traps for quantum simulation experiments. The atomic density inhomogeneity, together with the consequent position-dependent energy and time scales of cold atoms in traditional harmonic traps, makes it difficult to manipulate and detect the sample at a higher level. These problems are partially solved by optical box traps made of blue-detuned hollow beams. However, generating a high-quality hollow beam with high light efficiency for the box trap is challenging. Here, we present a scheme that combines the fixed optics, including axicons and prisms, to pre-shape a Gaussian beam into a hollow beam with a digital micromirror device (DMD) to improve the quality of the hollow beam further, providing a nearly ideal optical potential of various shapes for preparing highly homogeneous cold atoms. The highest power-law exponent of potential walls can reach a value over 100, and the light efficiency from a Gaussian to a hollow beam is also improved compared to direct optical shaping by a mask or a DMD. Combined with a one-dimensional optical lattice, a nearly ideal two-dimensional uniform quantum gas with different geometrical boundaries can be prepared for exploring quantum many-body physics to an unprecedented level.

The Future Needs of External Beam Radiotherapy in Portugal Until 2040

AimsExternal beam radiotherapy (EBRT) is essential to offer an effective cancer treatment, but it needs to be accessible, well-timed, and high-quality. There is a global lack of radiotherapy infrastructure and investment that compromises the cancer outcomes. The authors aim to quantify the future needs of EBRT until 2040 to cover the future demand. Materials and methodsBased on the Global Cancer Observatory estimate for new cancer cases in Portugal for 2040 it was calculated the optimal number of EBRT courses. The OUP is the proportion of new cancer cases that should receive EBRT at least once. In line with the International Atomic Energy Agency (IAEA) DIrectory of RAdiotherapy Centres and European SocieTy for Radiotherapy and Oncology - Health Economics in Radiation Oncology guidelines, we estimated the number of EBRT machines / Megavoltage (MV) units needed. Also, the authors followed the IAEA staffing guidelines. ResultsThe calculated median increase in the optimal number of EBRT courses for the year 2040 was found to be 18% when compared to the requirements in 2020. The projected number of optimal EBRT courses for 2040 was estimated to be approximately 34.000. Consequently, a range of 18 to 30 new EBRT machines/ MV units will need to be installed to adequately address the growing demand. To meet this demand, it is anticipated that a total of 28 to 46 radiation oncologists, 22 to 36 medical physicists, and 61 to 102 radiation therapists will be required. ConclusionThe deficit of EBRT machines / MV units in Portugal will require a change in the cancer related – policies and an investment to offer full access to EBRT treatments.

Quantifying donor site morbidity in anterior cruciate ligament reconstruction using peroneus longus tendon autograft

Objectives: The objective of this study was to assess the donor site morbidity in patients having anterior cruciate ligament reconstruction (ACLR) using peroneus longus tendon (PLT) autograft. Methods: A prospective cohort study was conducted at the orthopedic department of Pakistan Atomic Energy Commission General Hospital, Islamabad, from July 2021 to July 2023. A total of 150 patients aged between 20 and 40 years with an anterior cruciate ligament injury requiring ligament reconstruction were included in the study. Exclusion criteria included previous ankle ligamentous injuries, fractures or surgeries around the ankle, and high-risk sports like football. After the ACLR surgery, the patients were assessed for pain, range of motion (ROM), and muscle power in the 6th week, 3rd month, and 6th month. Return to jogging without discomfort at the ankle during 1st min of jogging was assessed at six months. Results: Of the 150 patients, 142 (94.6%) were male and 8 (5.4%) were female. The mean age of participants was 32.53 ± 4.78 years. Pain and loss of ROM around the ankle were reduced after six months compared to three months and six weeks, that is, P < 0.05. Muscle power was increased after six months (n = 152; 94.0%) (P < 0.001). In the 6th month, 133 patients (88.7%) were able to jog without discomfort around the ankle joint during the 1st min of jogging, but 17 patients (11.3%) started jogging after six months without discomfort at the ankle joint during the 1st min of jogging (P < 0.001). Conclusion: ACLR using the PLT autograft resulted in a good functional outcome, smooth rehabilitation with an early return to sports, and minimal complications at the donor site.

Legal boundaries: Ensuring protection amidst threats to the Zaporizhzhya Nuclear Power Plant in the Ukraine

This article aims to examine the protection accorded to nuclear power plants in international law, based on the example of the Zaporizhzhya Nuclear Power Plant in the context of the current Russian aggression against Ukraine and the ensuing international armed conflict. The authors attempt to answer the question of the legality of the attacks against the Zaporizhzhya Nuclear Power Plant. The research methods used are institutional-legal analysis and, supplementarily, a critical literature analysis. The institutional-legal analysis focuses on the examination of international treaties like Additional Protocol I to the Geneva Conventions, which constitutes the main legal reference point in this article, as well as on other documents that may not be binding (such as resolutions adopted by the International Atomic Energy Agency's General Conference or the Board of Governors, as well as statements and reports of other International Atomic Energy Agency's and United Nations' bodies). The main conclusion is that Russian attacks against the Zaporizhzhya Nuclear Power Plant were and continue to be illegal on multiple fronts. While the legal regulations appear adequate and capable of meeting the challenge posed by Russian attacks and occupation of the Zaporizhzhya Nuclear Power Plant, the problem lies with the political will of Russia to respect these rules.

Transfer functions for QA /QB international regulatory limits for the safe transport of radioactive materials

This paper presents a proposed revision of the International Atomic Energy Agency transport regulations, related to the A 1 and A 2 limit values used to determine the radioactive transport classification. Based on the ‘Q system’, a novel methodology was introduced to derive QA and QB values related to scenarios involving external exposure from a distant source. These values are key parameters that respectively represent the total effective dose and total equivalent dose to the skin, from all primary and secondary particles contributing to radiation exposure. The International Working Group (WG A 1/A 2) is established and associated with the TRANSSC Technical Expert Group on Radiation Protection. A review of the A 1 and A 2 values is performed in response to identified limitations within the existing Q system. The followed approach is based on Monte Carlo simulations that enabled the development of transfer functions aimed at reducing computational time and increasing the flexibility of dose evaluations for any radionuclide with known particle emission spectra. This method allows updating the QA and QB values to account for future data evolutions (decay data, fluence-to-dose conversion coefficients) and standardizing the calculation of regulation limits across all referenced radionuclides and scenarios related to external exposure. The transfer functions are established using three Monte Carlo simulation codes—FLUKA, Geant4, and MCNP—and address the previous limitations of the ‘Q system’, reflecting the latest International Commission for Radiation Protection recommendations and improvements in calculation techniques. The results of the WG show consistent agreement across the codes, with minor discrepancies observed at low primary energies due to statistical uncertainties and different handling of stopping power for electrons/positrons in the codes. This revised approach aligns with current standards and recommendations, ensuring that the radiological consequences of transport accidents are acceptable for the new A 1 and A 2 limits from a radiological protection perspective.

Tensile and creep properties of small specimens of reduced-activation ferritic steel F82H, and the correlation to standard specimen data

Background A reduced-activation ferritic/martensitic (RAFM) steel, F82H steel, is the primary candidate structural material for fusion reactor blanket. Small specimen test technique is essential to develop the blanket materials using limited irradiation volume in high flux neutron field. An international collaboration activity “Towards the Standardization of Small Specimen Test Techniques for Fusion Applications” has been initiated under the framework of the International Atomic Energy Agency Coordinated Research Project for Phase I from 2017 to 2021, and Phase II from 2022 to 2026. The present paper reports the preliminary results on tensile and creep tests as a summary of the above Phase I activity. Methods Tensile and creep tests were conducted at 550 and 650°C, using flat-plate SSJ type small specimens with various gauge thickness ranged from 0.14 to 1.2 mm, while gauge length and width are 5 and 1.2 mm, respectively. In addition, round bar type standard specimens with a gauge geometry of 6 mm in diameter and 30 mm in length was also tested for comparison. Results Tensile yield stress, ultimate tensile strength and uniform elongation were independent of the gauge thickness of SSJ specimens, and agreed with the data from the standard size specimens. On the other hand, total elongation was decreased with decreasing the thickness. In creep tests, rupture time was decreased with decreasing the gauge thickness of SSJ specimens. Standard size specimens exhibited shorter rupture time than the SSJ specimens. Conclusions The SSJ type specimens provided similar tensile parameters to those from the standard specimen, except total elongation. Creep rupture time of the SSJ specimens were different from the standard specimen, and decreased with decreasing the gauge thickness.

A Review of Fluoride Removal from Phosphorous Gypsum: A Quantitative Analysis via a Machine Learning Approach.

This review comprehensively explores fluoride removal from phosphogypsum, focusing on its composition, fluorine-containing compounds, characterization methods, and defluorination techniques. It initially outlines the elemental composition of phosphogypsum prevalent in major production regions and infers the presence of fluorine compounds based on these constituents. The study highlights X-ray photoelectron spectroscopy (XPS) as a pivotal method for characterizing fluorine compounds, emphasizing its capability to determine precise binding energies essential for identifying various fluorine species. Additionally, the first-principle density functional theory (DFT) is employed to estimate binding energies of different fluorine-containing compounds. Significant correlations are observed between the total atomic energy of binary fluorides (e.g., of alkali metals, earth metals, and boron group metals) and XPS binding energies. However, for complex compounds like calcium fluorophosphate, correlations with the calculated average atomic total energy are less direct. The review categorizes defluorination methods applied to phosphogypsum as physical, chemical, thermal, and thermal-combined processes, respectively. It introduces neural network machine learning (ML) technology to quantitatively analyze and optimize reported defluorination strategies. Simulation results indicate potential optimizations based on quantitative analyses of process conditions reported in the literature. This review provides a systematic approach to understanding the phosphogypsum composition, fluorine speciation, analytical methodologies, and effective defluorination strategies. The attempts of adopting DFT simulation and quantitative analysis using ML in optimization underscore its potential and feasibility in advancing the industrial phosphogypsum defluorination process.

Proposal of database of radiological characterization for decommissioning nuclear power plants

AbstractIn Korea, Kori Unit 1 was permanently closed in 2017 and scheduled for decommissioning. Kori Unit 1 is currently scheduled to undergo system decontamination and to be decommissioned by December 2038. Measures to properly control and remove radiological hazards must be established to go through decommissioning a nuclear power plant (NPP). Radiological characterization must precede NPP decommissioning. Radiological characterization generates a lot of data during this process. The consistency of radiological characterization data is important for systematically decommissioning NPPs. However, the data generated from radiological characterization may not be systematically managed because a database of radiological characterizations for Kori Unit 1 has not been properly established. Therefore, this study has proposed a database to be filled during radiological characterization in terms of occupational radiation exposure of personnel and decommissioning waste safety using key performance indicators presented by the International Atomic Energy Agency. From the perspective of occupational exposure, databases have been proposed for operational history investigations, decommissioning source term calculations, and investigation of the level of radiological contamination. From the perspective of the safety of decommissioning waste, databases were proposed for operational history investigation, decommissioning source term calculation, investigation of the level of radiological contamination, and investigation of radiological characteristics of decommissioning waste.

Impact of safety regulation on rare event occurrence: The case of nuclear power plants in Korea

Climate change mitigation and energy supply security are the most important issues worldwide. To attain carbon neutrality and restrict global warming to 1.5°C, expediting investments in energy sectors and facilitating the expansion of clean energy is imperative. Nuclear power generation, as a base load, contributes to the energy transition because it is low-carbon and can be deployed on a large scale; however, particular challenges arise due to the risk of accidents, radioactive waste management problems, and public acceptance. Considering the similarity between macroeconomic data and nuclear power generation data from a time-series perspective, this study estimates the frequency of rare event (RE) occurrence in nuclear reactors using macro time-series methodology. We employ the Bayesian Markov Chain Monte Carlo method, developed by Barro and Jin (2021), to estimate the likelihood of RE occurrences for the reactors using the panel data of electricity production (MWh) obtained from the International Atomic Energy Agency's Power Reactor Information System. The findings indicate that the frequency of RE occurrences significantly decreases as nuclear safety regulations strengthen and the regulatory workforce increases. Despite the limitations of being directly utilized as practical indicators for safety performance, observing its similar pattern with the World Association of Nuclear Operators performance indicators provides insights for policy implications in intermediate safety management aimed at preventing major disaster incidents.

Experimental and molecular dynamics multiscale study on sintering and interfacial reaction of Fe2O3/CaO particle system

High-temperature sintering and solid-state reaction within the intricate Fe2O3/CaO system are pivotal factors influencing material characteristics. The current work focused on the sintering and reaction behavior of Fe2O3/CaO particles at high temperatures with a multiscale study of in-situ high-temperature stage microscopy (HTSM) and molecular dynamics (MD). The laws governing atomic migration and the evolution of crystal structure during the sintering process were simulated at the nanoscale. The results elucidated that a heightened heating rate fosters particle shrinkage and concomitant reduction in surface area. The sintering activation energy (Esin) exhibited an increment proportional to the linear shrinkage of the particles. Furthermore, an augmented potential barrier in advanced stages impeded subsequent sintering behavior. Augmented temperature promoted the particle shrinkage and sintering neck formation, culminating in pore closure and a diminution in the free surface. However, this promotional effect attenuated with escalating temperatures. Particle shrinkage and sintering neck formation are contingent upon atomic migration and diffusion, with the growth of sintering necks primarily reliant on atom diffusion along the surface of the sintering necks. The atomic diffusion activation energy was determined to be 49.5 kJ/mol within the temperature range of 1073–1473 K. Within the Fe2O3/CaO system, the preferential generation of Ca2Fe2O5 (C2F) over CaFe2O4 (CF) was found, leading to a decrease in the atomic diffusion barrier and an enhancement of the diffusivity, with the latter dominating in later stages. The highest mobility of O2–, Fe3+, and Ca2+ was discerned in CF, and the sintering shrinkage of the particles predominantly hinges on the generation of CF.

Role of independent research at AERB for ensuring safety of nuclear facilities in India.

The mission of Atomic Energy Regulatory Board (AERB) of India is to ensure that the use of ionising radiation and nuclear energy in India does not cause unacceptable impact on the workers, members of the public and to the environment. AERB has the mandate to carry out detailed safety review for the siting, construction, commissioning, operation and decommissioning of nuclear and radiation facilities established within the country. To deliver and maintain a strong, credible and technically sound regulation, AERB has established the Safety Research Institute (SRI) at Kalpakkam with a robust technical infrastructure and wide knowledge base. This paper highlights the independent safety research activities carried out at SRI and its role to support and facilitate the decision-making process by AERB at various stages of regulatory review for ensuring safety of the nuclear facilities in India.

Methodology for shielding design and evaluation for container scanners.

There has been an increase in the use of high energy photon beam for container scanners in many countries for multi purposes such as detecting high atomic number materials which might be nuclear materials, drugs, high explosive materials and other contrabands etc. High energy photon beams generally 6 and 9 MV can be used for scanning such materials. However, it is important to ensure that radiation level beyond the container scanner installation is within the permissible dose limit specified by the national competent authority for the protection of public and radiation workers. In this paper, challenges in the biological shielding during the installation of high energy X-ray system for scanning vehicles containing suspected materials are discussed. The purpose of the present study is to develop a methodology for shielding design and evaluation for container scanner installations. The basic concept pertaining to shielding evaluation of radiotherapy installations provided in National Council on Radiation Protection and Measurements (NCRP)/International Atomic Energy Agency (IAEA) reports are referred, and appropriately used to calculate optimized shielding thicknesses requirements for container scanner installation. Workload is estimated based on number of containers scanned, machine ON time and dose rate at 1m. The shielding evaluation includes use of beam stopper in the primary beam, scattering by heterogeneous metallic scrap materials or any other suspected materials contained in the vehicle and their impact on the thickness of shielding walls. A model lay out plan to be used for installation of container scanner is developed. A methodology for shielding evaluation for various protective walls and ceiling of this model is also discussed. The study provides basic requirement for designing a structural room for installing 9MV container scanner from radiological safety view point.

Influence of a plasma focus device on the structural and optical properties of highly conductive AZO thin films

In the present work, we deposited Al-doped ZnO (AZO) thin films on microscope glass slides at different pressures (5, 10, 20, and 30 mTorr) using an EAEA-PFD (Plasma Focus Device of the Egyptian Atomic Energy Authority) without any extra heat treatment. Argon gas provided the radiant energy needed to form a crystalline AZO film. This study investigated the deposition and features of AZO thin films. The impact of changes in work pressure on the microstructure, morphology, and optical attributes of AZO films was reported. The results demonstrated that varying the work pressure significantly affects the microstructure, morphology, crystallinity, optical absorbance, and optical energy gap. The microstructure and morphology were evaluated through XRD and scanning electron microscopy (SEM). The optical properties were analyzed using a UVvis double-beam spectrophotometer within a wavelength range from 300 to 1100 nm. XRD patterns indicating a zinc-blende structure and the Williamson–Hall approach were used to estimate the structural parameters. The estimated trend in the particle size of the AZO film demonstrates a decrease from 82 ± 5 nm to 48 ± 5 nm as the pressure increases. The calculated energy gap, Egopt, increases from 3.53 eV to 3.69 eV with increasing work pressure. The conductivities in terms of both optical and electrical decreased with increasing work pressure of the AZO films.

In vivo Antiplasmodial Assessment of Phyllanthus odontadenius against Plasmodium berghei in NMRI Mice

Aims: Phyllanthus odontadenius is one of the genus Phyllanthus species, used for number diseases treatment including malaria. Malaria today poses a real public health problem for more than hundred countries, afflicted millions people and killed an estimated 405 000 in the World. The chemoresistance of Plasmodium falciparum to modern antimalarials which are either expensive, toxic or ineffective leads to the search for new antimalarials at lower cost, non-toxic and effective within plant biodiversity. Given the interest in various P. odontadenius crude extracts in vitro on P. falciparum, an in vivo study seems necessary in order to judge the extracts effectiveness of this plant. This study therefore aims to find justification for P. odontadenius secondary metabolites antiplasmodial activity which would have been revealed in the three samples from three different province sites. Study Design: Plants P. odontadenius samples from three province harvested and dried separately, plant phytochemistry screening realized, extracts preparation for antiplasmodial test, mice parasitization with P. berghei strain, orally administration drug; Parasiteamia determination using an immersion microscope. Place and Duration of Study: Department of Radiobiology, Applied Microbiology section, General Atomic Energy Commission, Regional Nuclear Studies Center of Kinshasa. MPI and pharmacognosy laboratories in the National Biomedical Research Institute (INRB). This work took place over the period from October 11, 2020 to March 12, 2021. Methodology: Phytochemical screening P. odontadenius samples was previously determined with the chemical reagent reactions and TLC. Then, P. odontadenius methanol extracts from aerial parts harvested in three sites (Kinshasa, Kasangulu and Kwango-bridge) were administered to test mice (12.5 mg/kg and 25 mg//kg bw) after infected mice with the Plasmodium berghei strain. DMSO 10% and quinine 10 mg/kg bw were also used as controls for comparison with the samples of P. odontadenius extracts. After 5 days, parasitemia of each test and controls mice was determined. Percent of parasitemia, parasite density and percent of inhibition were calculated. Finally, the effect dose 50 of each P. odontadenius specimen was finally determined. Results: Parasiteamia rates of negative control (DMSO 10%) was high (69.98±15.03%) comparing to positive control (27.43±11.46%) and tested mice with P. odontadenius extracts (12.5 and 25 mg/kg bw) which percent’s varied from 24.66±15.84% to 59.01±22.44%. Negative control presented high parasite density with 11,342 (±2,436) comparing to the positive control (4,447±1,857) and all P. odontadenius methanol extracts which varied from 3,995±2,343 for 25 mg/kg bw to 9,570±3,319 for 12.5 mg/kg bw. Parasiteamia reduction rates followed inversely parasite density, thus, Po3 25 mg/kg bw had high parasiteamia reduction rate (65.23%) comparing to positive control with 61.32% and to P. odontadenius methanol extracts. Po3 presented 2.44 mg/kg bw as effect dose 50 comparing to Po1 (2.93 mg/kg bw) and Po2 (2.68 mg/kg bw). Males mice were highly affected to P. berghei than the females. Conclusion: This study revealed that all specimens of P. odontadenius had good in vivo antiplasmodial activities on P. berghei. All P. odontadenius extracts showed good parasitaemia inhibition compared to negative control, but P. odontadenius from Kwango-brigde (Po3) presented good behavior concerning in vivo antiplasmodial activity in comparison to P. odontadenius from Kasangulu (Po2) and that from Kinshasa (Po1). However, further studies are necessary on the in vivo toxicity of the plant and on the medicinal form that could be applied.

Tertiary Magmatism in Northwestern Kalimantan: Probability of Volcanic Hazard to The Nuclear Power Plant Site Candidate at Gosong Beach, Bengkayang Regency

Gosong Beach in Bengkayang, West Kalimantan, is selected as a potential Nuclear Power Plant (NPP) site candidate. Volcanic and intrusive rocks are found in the radius of 150 km from it. Based on IAEA (International Atomic Energy Agency) standard, the main assessment target is volcanic rock that is younger than 10 Ma. However, there are Tertiary volcanic and intrusive rocks next to and cover a wide area around the NPP site that show volcanic activities over the Tertiary period. Therefore, it is necessary to investigate this group of rocks to understand its characteristics. This study aims to characterize the geochemistry and petrology of the Tertiary volcanic and intrusive rocks found in northwestern Kalimantan. The fieldwork was conducted to observe and to take Serantak volcanic rocks, Bawang dacite, Niut volcanics, and Sintang intrusion samples. The XRF and micro-XRF analyses were conducted to characterize the geochemical aspect, while petrography and AMICS analyses were conducted to characterize the mineralogical aspect. The result shows that Serantak volcanic rocks, Bawang dacite, Niut volcanics, and Sintang intrusion are derived from tholeiitic to calc-alkaline as a product of mantel partial melting in the subduction zone which go through fractional crystallization. The volcanic activity was initiated by the rise of primitive parental magma from partial melting in the shallow-depth subducted crust as indicated by the garnet-free HREE pattern, the enrichment of LILE and LREE, and the depleted HREE. The Tertiary magmatism in northwestern Kalimantan was found in a small activity with a small impact on the NPP candidate site at Gosong Beach, Bangkayang.

Hydrogen adsorption, migration and desorption on amorphous carbon: A DFT and AIMD study

Physisorption is the general dominating adsorption mode on pure carbonaceous materials. In this study, we examined if chemisorbed hydrogen can be accomplished without incorporating metals on carbon surfaces. We constructed two 100-atom amorphous carbon (a-C) models with different microenvironments (42 % 2-fold, 52 % 3-fold, and 6 % 4-fold coordinated carbon atoms and 18 % 2-fold and 82 % 3-fold, respectively) using ab initio molecular dynamics (AIMD) simulations to mimic activated carbon samples in reality. The structural, energetic, electronic structure and kinetic properties of hydrogen adsorption, migration, and desorption on the a-C surfaces were analyzed using density functional theory (DFT) and AIMD calculations, which showed that: (1) hydrogen molecules could spontaneously dissociate on the convex side of 2-fold coordinated carbon atoms. Physisorption of hydrogen molecules mainly took place on 3-fold coordinated carbon atoms. (2) Regarding the multiple hydrogen adsorption, the entire a-C model could uptake around 156 hydrogen atoms with the adsorption energy per hydrogen atom about −0.70 to −0.60 eV at high hydrogen pressure. In addition, we found that the average individual adsorption energy of a single hydrogen atom on different carbon atoms could be used as a quick prediction for the saturated hydrogen adsorption energy. (3) The migration barrier of a hydrogen atom between two adjacent carbon atoms was about 2 eV at both low and high hydrogen coverage, indicating that hydrogen mobility on this designed a-C model was low. The desorption of a hydrogen molecule can take place at 300 K using AIMD calculation, but not for atomic hydrogen desorption. In this work, we demonstrated that hydrogen chemisorption could take place on this designed a-C without the decoration of metal particles to enhance hydrogen adsorption amounts. The materials design to balance hydrogen chemisorption, migration, and desorption shall be considered in the future.

Incorporating Noncovalent Interactions in Transfer Learning Gaussian Process Regression Models for Molecular Simulations.

FFLUX is a quantum chemical topology-based multipolar force field that uses Gaussian process regression machine learning models to predict atomic energies and multipole moments on the fly for fast and accurate molecular dynamics simulations. These models have previously been trained on monomers, meaning that many-body effects, for example, intermolecular charge transfer, are missed in simulations. Moreover, dispersion and repulsion have been modeled using Lennard-Jones potentials, necessitating careful parametrization. In this work, we take an important step toward addressing these shortcomings and show that models trained on clusters, in this case, a dimer, can be used in FFLUX simulations by preparing and benchmarking a formamide dimer model. To mitigate the computational costs associated with training higher-dimensional models, we rely on the transfer of hyperparameters from a smaller source model to a larger target model, enabling an order of magnitude faster training than with a direct learning approach. The dimer model allows for simulations that account for two-body effects, including intermolecular polarization and charge penetration, and that do not require nonbonded potentials. We show that addressing these limitations allows for simulations that are closer to quantum mechanics than previously possible with the monomeric models.