Transport Method Research Articles

Revenue management method and critical techniques of railway passenger transport

PurposeRevenue management (RM) is a significant technique to improve revenue with limited resources. With the macro environment of dramatically increasing transit capacity and rapid railway transport development in China, it is necessary to involve the theory of RM into the operation and decision of railway passenger transport.Design/methodology/approachThis paper proposes the theory and framework of generalized RM of railway passenger transport (RMRPT), and the thoughts and methods of the main techniques in RMRPT, involving demand forecasting, line planning, inventory control, pricing strategies and information systems, are all studied and elaborated. The involved methods and techniques provide a sequential process to help with the decision-making for each stage of RMRPT. The corresponding techniques are integrated into the information system to support practical businesses in railway passenger transport.FindingsThe combination of the whole techniques devotes to railway benefit improvement and transit resource utilization and has been applied into the practical operation and organization of railway passenger transport.Originality/valueThe development of RMRPT would provide theoretical and technical support for the improvement of service quality as well as railway benefits and efficiency.

Selenophosphate Pb2P2Se6 Single Crystals Growth by Chemical Vapor Transport (CVT) Method for Radiation Detection.

The heavy metal selenophosphate Pb2P2Se6 emerges as a promising room-temperature X-ray/γ-ray detectors due to its high resistivity, robust radiation-blocking capability, and outstanding carrier mobility-lifetime product, etc. However, the high activity of phosphides poses significant impediment to the synthesis and single crystal growth. In this work, we have prepared high-quality Pb2P2Se6 single crystals with using the chemical vapor transport (CVT) method. The XRD analysis combined with EDS result confirmed the uniform composition of the resulting as-grown single crystals, while UV-Vis-NIR transmittance spectra revealed the bandgap of 1.89 eV. Selected area electron diffraction patterns indicated the crystal belonged to the P21/c(14) space group. Additionally, the Au/Pb2P2Se6/Au device is fabricated, which exhibits a robust X-ray response with a sensitivity of 648.61 μC Gy-1 cm-2 at 400 V mm-1 under 50 kVp. Notably, the device also excels in alpha particle detection, boasting a resolution of ~14.48 % under a bias of 400 V bias. The hole mobility-lifetime product (μτ)h of Pb2P2Se6 is estimated to be ~2.58×10-5 cm2 V-1. The results underscore potential applications of Pb2P2Se6 crystal is in the field of the semiconductor radiation detectors.

Factors related to the intention of choosing shared E-scooters for metro transfer: A survey study integrating weather perception into satisfaction evaluation from Changsha.

Shared E-scooter (SE) travel is a low-carbon transportation method that can be further enhanced by integrating with metro systems. This study aims to quantify the impact of the built environment, attitude preferences, weather perception, and other factors on the evaluation and intention to use the "SE-metro transfer" travel mode, as well as how to efficiently and concisely measure and model these effects. Empirical analysis was conducted using questionnaire data from Changsha, China, with 683 participants surveyed. Three satisfaction models were established and compared based on the Technology Acceptance Model (TAM), and an optimal M2 model was expanded to incorporate users' subjective perceptions of weather, proposing a method to simplify questionnaire length. The study found that well-designed vehicles and infrastructure, along with necessary supporting facilities, play important roles in enhancing SE usage. However, there are still many areas for optimization in Changsha's SE policies. Despite the advantages of SE in terrain and physical fitness, which have significantly expanded and changed their user base compared to traditional shared bicycles, there is still much potential to adapt to the middle-aged and older user groups. The results of this study can provide valuable insights for professionals and government officials in designing systems, constructing infrastructure, and formulating policies.

Sustainable open pit mining through GHG-conscious short-term production scheduling

ABSTRACT The mining industry is a notable contributor to global greenhouse gas (GHG) emissions, posing challenges to achieving the Paris Agreement’s goal of capping emissions at 30 Gt CO2-equivalent annually by 2030. This paper introduces a novel Mixed Integer Linear Programming (MILP) model tailored for short-term open-pit mine planning that integrates environmental considerations, particularly GHG emissions, alongside economic objectives. The model handles complex operational challenges including block sequencing, multiple transport destinations, and stockpile management. Additionally, it provides the opportunity to examine the adoption of In-Pit Crushing and Conveying (IPCC) systems as the main transport method, an innovative approach aimed at reducing emissions from haulage – which accounts for over 35% of GHG emissions in open-pit mining. Applied to a case study in an iron ore mine, the model not only considers the environmental benefits of IPCC systems compared to traditional truck and shovel (TS) operations but also highlights significant reductions in haulage costs and carbon tax liabilities. The findings demonstrate that fixed IPCC (FIPCC) systems, in particular, offer substantial decreases in GHG emissions, presenting a compelling case for their broader adoption in the industry.

Analysis of Leakage and Diffusion Characteristics and Hazard Range Determination of Buried Hydrogen-Blended Natural Gas Pipeline Based on CFD.

Injecting hydrogen into natural gas pipelines is an economical and efficient method of hydrogen transportation. However, the addition of hydrogen leads to significant hydrogen corrosion and embrittlement in the pipelines, especially in harsh and concealed underground conditions, where leak accidents are frequent and difficult to detect. This Article uses Le Chatelier's Principle to determine the hazardous range of hydrogen-blended natural gas (HBNG) by employing numerical simulation, it examines the gas leakage and diffusion characteristics before and after hydrogen injection as well as under different hydrogen blending ratio (HBR). Additionally, considering the density of the mixed gas, a prediction model for the diffusion hazard range of hydrogen-mixed natural gas is established based on multivariate regression theory. The results show that after a leakage occurs in HBNG the diffusion range in soil is wider compared to methane, with higher corresponding pressure and velocity values. Moreover, as the HBR increases, the farthest danger range (FDR) of the HBNG also increases. When the leakage of the buried HBNG pipeline occurs for 1 min, the difference in FDR between HBR 25% and HBR 5% is 0.005 m. After 30 min, this difference increases to 0.019 m, indicating that with longer leakage duration, the potential explosion risk resulting from increased HBR becomes greater. Factors such as pipeline pressure increase, larger leak hole size, and decreased burial depth all contribute to an increase in FDR, with pipeline pressure change having the greatest impact and burial depth change having the smallest impact. The maximum error of the predicted model for the diffusion hazard range of hydrogen-mixed natural gas is 9.385%, and the average error is 2.376%, demonstrating the accuracy of the prediction results. This study provides guidance for monitoring underground hydrogen-blended natural gas pipeline leaks, offers a basis for determining the repair range of pipelines, and ensures the safe transportation of hydrogen-mixed natural gas pipelines.

Nanoscale dosimetry for a radioisotope-labeled metal nanoparticle using MCNP6.2 and Geant4.

Metal nanoparticles (MNPs) labeled with radioisotopes (RIs) are utilized as radio-enhancers due to their ability to amplify the radiation dose in their immediate vicinity. A thorough understanding of nanoscale dosimetry around MNPs enables their effective application in radiotherapy. However, nanoscale dosimetry around MNPs still requires further investigation. This study aims to provide insight into the radio-enhancement effects of MNPs by elucidating nanoscale dosimetry surrounding MNPs labeled with Auger-emitting RIs. We particularly focus on distinguishing the respective dose contributions of photons and electrons emitted by Auger-emitting RIs in the context of dose enhancement. A 50nm diameter NP of silver (Ag) core and gold (Au) shell (Ag@Au NP) was assumed to emit mono-energetic electrons and photons (3, 5, 10, 20, and 30keV), or the energy spectrum corresponding to one of three Auger-emitting RIs (103Pd, 125I, and 131Cs) from the Ag core. Nanoscale radial dose distributions around a single radioactive Ag@Au NP were evaluated in spherical shells of water. Monte Carlo simulations were conducted using single-event and track structure transport methods implemented in MCNP6.2 and Geant4-DNA-Au physics, respectively. To evaluate the extent of radio-enhancement by the Ag@Au NP, two scenarios were considered: Ag@Au NPs (Au shell included) and Ag@water NPs (Au shell replaced by water). The radial doses of 10, 20, and 30keV electrons estimated by both codes were comparable. However, the radial doses of 3 and 5keV electrons by MCNP6.2 were much larger near the NP surface than those by Geant4. There was a dose enhancement of a few % to tens % by the Au shell in the region of the NP surface to 10µm, depending on the electron energy. The radial doses of photons with the Au shell were higher up to their secondary electron ranges than those without the Au shell. The maximum dose enhancement factor of photons occurred at 20keV and was 63.4 by MCNP6.2 and 50.5 by Geant4. The overall radial doses of electrons were 1-2 orders of magnitude larger than those of photons. As a result, in cases of RIs emitting both electrons and photons, the radial doses up to electron ranges were dominantly governed by electrons. The dose enhancement estimated by both codes for the RIs ranged from a few % except in the immediate vicinity of the NP surface. Given the dominant contribution of electrons to radial doses of MNP labeled with Auger-emitting RIs, physical dose enhancement expected by interactions with photons was hindered. Since there are no available RIs emitting exclusively photons, achieving enhanced physical doses within a cell through a combination of MNPs and RIs appears currently unattainable. The radial doses of photons near the NP surface exhibited considerable discrepancies between the codes, primarily attributed to low-energy electrons. The difference may arise from higher cross-sections of Au inelastic scattering in Geant4-DNA-Au compared to MCNP6.2.

Transportation Barriers in Pediatric Orthopaedic Clinic Visits.

To identify what transportation barriers pediatric patients face when traveling to a major metropolitan orthopaedic center, how these barriers affect care, and what changes can be made to address this issue. A cross-sectional transportation survey was administered to 107 caregivers of patients being seen in the orthopaedic clinic at a tertiary children's hospital in a large metropolitan area. Using logistic regression analysis, we compared socioeconomic characteristics, transportation methods, and scheduling practices among caregivers who reported missing at least one visit in the past and those who reported never missing a visit. 13% (14/108) of caregivers reported missing one or more past visits due to late arrival or transportation issues. Families that traveled more than 45 minutes to clinic (P = 0.04), waited more than one week to schedule a visit (P = 0.002), or reported difficulty scheduling a visit (P = 0.02) were significantly more likely to have a history of nonattendance. In addition, patients who were nonambulatory (P = 0.007), used a mobility device (P = 0.007), or were non-White (P < 0.05) were significantly more likely to have missed a visit. Travel time, difficult or delayed scheduling, and patient ambulatory status were all associated with missing orthopaedic clinic visits although other socioeconomic factors were not related. Interventions to improve orthopaedic clinic attendance should focus on promoting accessibility for patients with mobility limitations and encouraging simple and timely scheduling practices.

Observational Study of the Clinical Impact of E-scooter Injuries at a Major Trauma Centre.

Background Due to the increased use of e-scooters in the UK, associated injuries have increased, and its cost has increased as well. Worldwide data on injuries related to e-scooter use are relatively limited, owing to the short duration since their first introduction to the public. Aim There has been an increase in using e-scooters as a method of transport recently. It was noticed that the severity and frequency of its injuries are increasing as well. This study focuses on the frequency of e-scooter-associated injuries, especially open fractures, and to evaluate its burden on the health system. Methods Data on e-scooter injuries were extracted from our trauma database from November 2017 to July 2022. Patients' notes and images were reviewed. Outcome measures were the type of injuries: site of bony fractures, closed vs. open fracture (using Anderson and Gustilo classification), number of operations, complications, and length of hospital stay. Results The number of patients enrolled was 104. The mean age was 34.3 years, and 78.8% (n = 82) were male. The main mechanism of injury was riding (91%, n = 95) vs. hitting by an e-scooter (9%, n = 9). Injured patients were more likely not to wear helmets (82% of total injured patients). Patients with bony injuries were 65.4% (n = 68), with 22.1% (n = 15) of them being open fractures. The most common bony injuries were lower limb-only fractures at 45.6% (n = 31), then upper limb-only injuries at 39.7% (n = 27). Combined upper and lower limb cases were 8.8% (n = 6), and pelvic injuries were 5.9% (n = 4). Head and neck injuries composed 23.1% (n = 24) of the reported injuries, including intracranial haemorrhages (9.6%, n = 10), extensive traumatic brain injury (3.8%, n = 4), haematoma/lacerations (3.8%, n = 4), cervical spine fractures (1.9%, n = 2), and skull fractures (1.9%, n = 2). The mean duration of hospital stay was 8.6 days, and 9.6% (n = 10) of patients needed intensive therapy unit(ITU) admission. The number of patients presented as trauma calls was 55.8% (n = 58). Patients who needed surgical intervention either under orthopaedics or other specialties were 52.9% (n = 55) and 21.2% (n = 22) of total patients had complications either due to surgical intervention or a long hospital stay. Conclusion E-scooter riding can lead to serious injuries that can end with limb- or life-threatening conditions. The most common demographic characteristics were adults in their early 30s. There should be more emphasis on wearing protective gear like wrist and elbow guards in addition to helmets. Future prospective studies with larger cohorts across multiple regions and hospitals are necessary to truly characterize the nature and cost of e-scooter injuries.

Olivine-Type Fe2GeX4 (X = S, Se, and Te): A Novel Class of Anode Materials for Exceptional Sodium Storage Performance.

The introduction of abundant metals to form ternary germanium-based chalcogenides can dilute the high price and effectively buffer the volume variation of germanium. Herein, olivine-structured Fe2GeX4 (X = S, Se, and Te) are synthesized by a chemical vapor transport method to compare their sodium storage properties. A series of in situ and ex situ measurements validate a combined intercalation-conversion-alloying reaction mechanism of Fe2GeX4. Fe2GeS4 exhibits a high capacity of 477.9mA h g-1 after 2660 cycles at 8 A g-1, and excellent rate capability. Furthermore, the Na3V2(PO4)3//Fe2GeS4 full cell delivers a capacity of 375.5mA h g-1 at 0.5 A g-1, which is more than three times that of commercial hard carbon, with a high initial Coulombic efficiency of 93.23%. Capacity-contribution and kinetic analyses reveal that the alloying reaction significantly contributes to the overall capacity and serves as the rate-determining step within the reaction for both Fe2GeS4 and Fe2GeSe4. Upon reaching a specific cycle threshold, the assessment of the kinetic properties of Fe2GeX4 primarily relies on the ion diffusion process that occurs during charging. This work demonstrates that Fe2GeX4 possesses promising practical potential to outperform hard carbon, offering valuable insights and impetus for the advancement of ternary germanium-based anodes.

К безопасности труда при транспортировании гидросмесей по трубопроводу

The article describes the technology of pipeline transportation of hydraulic mixtures for stowing at underground mining. The relevance of optimization of the hydraulic mixture transportation processes is based on the fact that filling the excavated space during its abandonment is the main factor of injury prevention among workers and the integrity of industrial facilities. The aim of the study is to detail the hardening mixture transportation methods for increased distance compared to the reached distance. The maximum damage factor is a rockslide into the open excavated space; therefore, the delivery of stowing pulp to the location of use minimizes the hazard for miners. The advantages of the proposed solution are substantiated by the adopted study methods. The study results can be used for the development of a set of protective measures. The applied mixture transportation methods have been analyzed. The practices of hydraulic mixture transportation for the distance of 2.5 km, which exceeded the best global achievements, have been described. Models of the description of hydraulic mixture transportation have been provided including the models obtained by calculations and experimental pressure loss. The operation schedules in forced mode for pipeline transport have been provided. It has been demonstrated that the optimization of aspects of the issue is specifically relevant for the intensification of processes of metal deposit development. The outcomes of the experimental study can be used when involving accumulated washery refuse in the treatment. It is recommended to determine the parameters of efficient delivery of hydraulic mixtures in vibration-induced mode by modelling in accordance with the criteria of distance and reliability of transportation. The recommendations on the use of hydraulic mixture delivery technology in forced mode can be required when developing mineral deposits by open and underground methods and training highly qualified personnel.

The Hydrogen Vehicle in the Context of the Sustainable Development of the Green Road Transport System

Abstract The scientific work presents concrete research carried out by the authors to implement some concepts of technical and managerial nature, so that those interested in this field can get acquainted with a certain way of exposing the problems concerning the hydrogen-powered vehicle, in the context of the sustainable development of the ecological road transport system. At the moment, the car whose energy for propulsion is generated by means of hydrogen or hydrogen fuel cells does not enjoy a high popularity among users, due to the very high purchase price (where we have high technology, we also have a price to match - a fuel cell is more expensive than an electric battery), the reluctance of the population to use this type of fuel, defined by the danger of explosions and fires generated by hydrogen, and the lack of hydrogen refueling stations in Romania and in some European countries. The use of alternative fuels in internal combustion piston engines has the advantage of significantly reducing pollution due to combustion products. With regard to the direct use of hydrogen as a fuel in internal combustion piston engines, we can say that it has proved its inefficiency, because the hydrogen injected or sucked directly into the engine cylinders is unstable, produces uncontrolled burns and detonations, and in the liquid state it is very difficult to store, it requires special transport methods, hydrogen tanks must be armored with Kevlar because hydrogen in the event of a car accident can explode. For example, if we use it as a fuel in a diesel engine, hydrogen may not ignite itself because the self-ignition temperature in the cylinders of compression-ignition engines is high (600°C). However, at a normal stoichiometric ratio, hydrogen has a high flame rate, much higher than gasoline. This creates a thermodynamic cycle of the thermal engine almost perfectly, but ideally, let us not forget that in poor mixtures of air-hydrogen the flame propagation speed is considerably reduced. The compression ratio of the engine is of utmost importance because it is finally defining the thermal efficiency of the engine. In the following, we present a technical and managerial study with engineering nuances, through which readers can look and understand the stage of development, place and role of the vehicle propelled by hydrogen fuel cells. Finally, the conclusions and further directions of research and development in the field addressed are presented.

Transport of American Bullfrogs with Moistened Foam and without Foam: Plasma Biochemistry and Erythrogram Responses

This study aimed to evaluate two transportation methods (with moistened foam and without foam) for 10 h on blood parameters of bullfrogs 0, 6, 12, 24, and 48 h after transportation. There was no mortality. The glucose increased at 0 and 12 h after transportation and returned to baseline at 24 h in both transportations. Triglycerides increased at 0 and 6 h in both transportations and were restored 12 h after transport with foam and 24 h in transport without foam. Plasma proteins and globulins increased at 0 h after transportation under both transportations. After 48 h, there was a reduction in transport without foam. Globulins decreased 48 h under both transportations. Albumin increased at 12, 24, and 48 h after both transportations. Transport with foam had high albumin. The albumin/globulin ratio increased 24 and 48 h after both transportations. The number of erythrocytes increased at 0 h and recovered after 6 h in transport with foam and 12 h in transport without foam. Hematocrit and hemoglobin increased at 0 h and recovered at 6 h in both transportations. MCV increased 48 h after transportation with foam. MCHC decreased 12, 24, and 48 h after both transportations. MCH was lower in the transport carried out with foam.

Probing spin hydrodynamics on a superconducting quantum simulator

Characterizing the nature of hydrodynamical transport properties in quantum dynamics provides valuable insights into the fundamental understanding of exotic non-equilibrium phases of matter. Experimentally simulating infinite-temperature transport on large-scale complex quantum systems is of considerable interest. Here, using a controllable and coherent superconducting quantum simulator, we experimentally realize the analog quantum circuit, which can efficiently prepare the Haar-random states, and probe spin transport at infinite temperature. We observe diffusive spin transport during the unitary evolution of the ladder-type quantum simulator with ergodic dynamics. Moreover, we explore the transport properties of the systems subjected to strong disorder or a tilted potential, revealing signatures of anomalous subdiffusion in accompany with the breakdown of thermalization. Our work demonstrates a scalable method of probing infinite-temperature spin transport on analog quantum simulators, which paves the way to study other intriguing out-of-equilibrium phenomena from the perspective of transport.

4IR Applications in the Transport Industry: Systematic Review of the State of the Art with Respect to Data Collection and Processing Mechanisms

Transportation systems through the ages have seen drastic evolutions in terms of transportation methods, speed of transport, infrastructure, technology, connectivity, influence on the environment, and accessibility. The massive transformation seen in the transportation sector has been fueled by the Industrial Revolutions, which have continued expansion and progress into the fourth Industrial Revolution. However, the methodologies of data collection and processing used by the many drivers of this progress differ. In order to achieve a better understanding of the impact of these technologies, in this study, we methodically reviewed the literature on the subject of the data collection and processing mechanisms of 4IR technologies in the context of transport. Gaps in present practices are identified in the study, especially with regard to the integration and scalability of these technologies in transportation networks. In order to fully reap the rewards of 4IR technologies, it is also necessary to apply standardized methods for data gathering and processing. In this report, we offer insights into current obstacles and make recommendations for future research to solve these concerns through a comprehensive evaluation of the literature, with the goal of promoting the development of intelligent and sustainable transportation systems.

Physiological assessment of the effects of experimental capture and transport in Pacific spiny dogfish

Sharks are collected from the wild as live specimens for display in aquariums and use in research. The methods by which live sharks are captured and transported can be associated with sub-lethal physiological outcomes or even mortality, which requires evaluation to determine optimal collection and transport methods for a given species. The present study evaluated the primary (i.e., endocrine) and secondary (i.e., biochemical) stress responses and mortality in Pacific spiny dogfish (Squalus suckleyi) following capture and subsequent transport between experimental rod-and-reel angling and longline fishing. Dogfish were resilient to transport following capture by either method, exhibiting no at-vessel mortality and 0.03% delayed mortality. Longline captured dogfish exhibited signs of primary (i.e., elevated corticosterone) and secondary (i.e., elevated plasma potassium, osmolality, glucose, and lactate; decreased blood pH) stress responses, whereas dogfish that experienced rod-and-reel capture and transport only exhibited a secondary stress response (i.e., elevated plasma potassium, osmolality, and lactate; decreased blood pH). Together, these data demonstrate that Pacific spiny dogfish are robust to capture and transport using experimental hook-and-line fishing techniques.

Geographic Information System in the Optimization of Tourist Routes in the City of Faro (Algarve, Portugal)

This work aims to map the optimal routes based on time and distance, via e-scooters and walking, to visit 54 historical heritage sites in Faro. Implementing these routes promotes environmental sustainability by reducing CO2 emissions and encouraging healthier, greener tourism. The route optimization was conducted in ArcGIS, utilizing the Network Analyst extension and vector data obtained from OpenStreetMap. The results showed that there are routes that can be completed in one or more days, depending on visitors’ availability, physical capacity, or their chosen method of transportation. The optimal route to visit the 54 historical heritage sites forms a closed circuit spanning 17.35 km. If visits are split into two routes, one covering 31 monuments in the old city and the other 24 monuments in the exterior area of the urban center, the optimal closed-circuit routes measure 6.16 km and 11.31 km, respectively. This study is expected to enhance tourism promoted by the Faro municipality and make it more environmentally friendly.

Development of Multigroup Monte Carlo Neutron Transport Method with Regionwise Even-Parity Discontinuity Factor

The multigroup Monte Carlo (MC) neutron transport method with a regionwise even-parity discontinuity factor (REPDF), i.e. the discontinuity factor (DF)–MC method, is developed with the aim to provide a reference solution for deterministic transport calculations with DF. Applying the analogy with optics, neutrons are transmitted or reflected at a region surface during random walks. The probability of transmission or reflection is determined by REPDFs in adjacent regions. The DF is traditionally used in deterministic neutron transport methods to reduce the discretization error due to spatial homogenization and energy condensation. The DF-MC method can treat DF in the framework of the multigroup MC method. In this paper, the weight cancellation technique based on the closest pair of points using the divide-and-conquer algorithm is used because negative weights appear due to the neutron reflection. The REPDF is calculated by the method of characteristics (MOC). The verification calculations are carried out in the pin-by-pin homogenized and assembly homogenized KAIST-2A core geometry. The DF-MC calculation can reproduce the results of the MOC with the REPDF. These results demonstrate the principle of the DF-MC method and extend the application of the DF to the probabilistic neutron transport method.

EVALUATING AND OPTIMIZING THE HAULED CONTAINER SYSTEM (HCS) IN PT. KAMIBOX MAJU SEJAHTERA'S WASTE MANAGEMENT OPERATION

This study evaluates the Hauled Container System (HCS) used in PT. Kamibox Maju Sejahtera's waste management operations. The HCS is a transportation method to transport containers filled with waste and recyclables from collection points to processing or disposal facilities, at PT. Kamibox Maju Sejahtera vehicles travel from a centralized hub in Cisauk to specific pickup locations to load containers. Each vehicle typically handles one location per operational cycle and then transports the loaded container to its destination. Our analysis shows that the HCS system currently enables approximately 2.45 trips per day, which translates to two practical daily trips. This system's simplicity and directness provide ease of management and reduce contamination risk, reassuring the audience about its current effectiveness. The study further explores fuel efficiency and costs, revealing that while the Gran Max is the most fuel-efficient, the Colt Diesel is the most cost-effective. Recommendations include optimizing vehicle use and considering more fuel-efficient alternatives to improve sustainability and reduce operational costs. The findings serve as a guide for PT. Kamibox Maju Sejahtera and similar enterprises were aiming for sustainable waste management.

Creating high, portable proton polarization with photo-excited triplet DNP

Dynamic nuclear polarization (DNP) is a powerful tool to polarize nuclear spins and enhance the intensity of their magnetic resonance signal. For DNP a sample is doped with an agent providing unpaired electron spins. Then the sample is cooled in a strong magnetic field to polarize these electron spins and a microwave field is applied to transfer this polarization to the nuclear spins. While DNP is very efficient, it has two inherent issues: the electron spins needed to polarize the nuclear spins are also the main source of polarization decay. Furthermore, polarizing the electron spins requires strong magnets and powerful cryogenics, that may obstruct further use of the polarized nuclear spins.These issues can be addressed by using the electron spin of photo-excited triplet states for DNP. After DNP the light creating the electron spins can be shut off, thus eliminating the main source of decay of the nuclear polarization. Moreover, for some well-chosen molecules the photo-excitation process creates the triplet state in a highly polarized state, so magnets and cryogenics can be significantly simplified.The present article presents the state of the art of producing a high proton polarization – up to 0.80 – with a long lifetime – typically 50 h at liquid nitrogen temperature and in a field of 0.75 T – using the photo-excited triplet state of pentacene in a naphthalene host. It describes sample preparation, experimental equipment and procedures required to obtain this result, as well the theoretical background required to maximize the polarization transfer from the triplet spins to the proton spins and to optimize the photo-excitation process. It finishes with methods for long-distance transport and final application of polarized samples.

Experimental validation of the 3-D neutron kinetics algorithm of RAPID using the JSI TRIGA Mark-II reactor

The high-fidelity simulation of reactor kinetics, with the ability of calculating detailed 3-D time-dependent distributions of the nuclear quantities of interest, is an important challenge in the field of nuclear engineering. As the industry moves towards innovative reactor designs and the financing and licensing of prototypes becomes increasingly complex, there is an increasing need of best-estimate and high-fidelity codes that are capable of replacing the computational tools that have been fine-tuned for LWRs using years of operation data and validation against benchmark facilities. Traditional neutron transport software either has to rely on significant modeling approximations or requires an impractical amount of computer time to calculate accurate and detailed solutions to the transport problems, failing to meet the need of the industry to simulate numerous scenarios over a relatively small time. RAPID is a software that relies on the Multi-stage Response-function Transport (MRT) methodology to achieve high-fidelity accurate solutions to the neutron transport problem by pre-calculating a database of response functions or coefficients that are then combined and interpolated to calculate the nuclear quantities of interest in seconds to minutes on a single computer core. In this article, the recently developed algorithms for 3-D time-dependent simulation of reactor kinetics and for control rods movement in the reactor core are validated using experiments performed at the Jožef Stefan Institute (JSI) TRIGA Mark-II reactor. The experiments were designed and performed with the goal of RAPID’s validation. In particular, time-dependent responses from four fission chambers located in the TRIGA core were collected and compared to RAPID-calculated values. The comparison of RAPID’s predictions to measured data shows very good agreement, demonstrating the ability of RAPID of calculating detailed 3-D time-dependent fission source distributions for a reactor kinetic problem that would be impractical to model with traditional neutron transport codes. In addition, it is demonstrated how RAPID is capable of obtaining a high level of accuracy within seconds to minutes on a single computer core, with a significant speedup with respect to state-of-the-art neutron transport methods.