bluuebunny/crossref_metadata_2025 huggingface dataset:
Trichinella britovi infection in wild boar in Portugal
Authors: Vieira‐Pinto Madalena , Fernandes Ana Raquel Garcez , Santos Maria Helena , Marucci Gianluca
Published: January 2021

Trichinella spp. infection occurs when a host ingests muscle tissue containing infective larvae (L1 stage). Wild boar meat and its products represent the second largest source of human trichinellosis worldwide. For this reason, and since that in Portugal wild boar is the most hunted large game specie, the laboratory of Technology, Quality and Food Safety (TQFS) from the University of Trás‐os‐Montes e Alto Douro created a free service to test wild boar meat for Trichinella spp. From December 2015 to February 2020, and 857 samples were analysed. From those, the majority (719/857, 83.9%) were tested after October 2018 when a specific national legislation came into force, demanding that meat from wild boar hunted in a defined risk area should be tested for Trichinella spp. Under TQFS laboratory activity, in January 2020, a positive case was identified, being the first molecular confirmation of Trichinella britovi infection in wild boar in Portugal. Additionally to this activity, in 2019, a questionnaire was submitted to 100 hunters to acquire information about wild boar meat usage and consumption behaviours. From the total respondents, 86% declared they intended to use meat for private consumption. Of those, 93% also stated that have sold part of the meat and/or homemade sausages, the majority (80%) without prior testing for Trichinella spp., as required by EU Regulation. These results alert the hunters to a risk for human infection, which could be extended to outside the hunter's household. Given the actual epidemiological situation, it should be emphasized that testing for Trichinella spp. in wild boar meat should be maintained and reinforced, particularly in the risk area. The results presented in this report strongly support the importance of specific national legislation to mitigate the risk of trichinellosis due to consumption of non‐tested wild boar meat.
Bacteriophage as an alternative to prevent reptile‐associated Salmonella transmission
Authors: Kwon Jun , Kim Sang Geun , Kim Hyoun Joong , Giri Sib Sankar , Kim Sang Wha , Lee Sung Bin , Park Se Chang
Published: January 2021

Salmonellosis is a major global public health issue; its most common infection, gastroenteritis, accounts for approximately 90 million illnesses and 150,000 mortalities per year. Eradicating salmonellosis requires surveillance, prevention and treatment, entailing large expenditures. However, it is difficult to control Salmonella transmission because it occurs via multiple routes; exotic reptiles are a reservoir of Salmonella and comprise one such route. As the popularity of exotic pets and animal exhibition has increased, human encounters with reptiles have also increased. As a result, reptile‐associated salmonellosis (RAS) has been recognized as an emerging disease. The development of antimicrobial resistance in RAS‐causing Salmonella sp. requires alternatives to antibiotics. In this study, bacteriophages have been established as an alternative to antibiotics because only target bacteria are lysed; thus, they are promising biocontrol agents. Here, bacteriophage pSal‐SNUABM‐02, which infects and lyses reptile Salmonella isolates, was isolated and characterized. The morphology, host range, growth traits and stability of the phage were investigated. The phage was assigned to Myoviridae and was stable in the following conditions: pH 5–9, 4–37°C, and ultravioletA/ultravioletB (UVA/UVB) exposure. Salmonella clearance efficacy was tested using planktonic cell lysis activity and biofilm degradation on polystyrene 96‐well plates and reptile skin fragments. The phage exhibited vigorous lysis activity against planktonic cells. In in vitro biofilm degradation tests on reptile skin and polystyrene plates, both low‐ and high‐concentration phage treatments lowered bacterial cell viability by approximately 2.5–3 log colony‐forming units and also decreased biomass. Thus, bacteriophages are a promising alternative to antibiotics for the prevention and eradication of RAS.
Antimicrobial resistance clusters in commensal Escherichia coli from livestock
Authors: Hesp Ayla , ter Braak Cajo , van der Goot Jeanet , Veldman Kees , van Schaik Gerdien , Mevius Dik
Published: January 2021

To combat antimicrobial resistance (AMR), policymakers need an overview of evolution and trends of AMR in relevant animal reservoirs, and livestock is monitored by susceptibility testing of sentinel organisms such as commensal E. coli. Such monitoring data are often vast and complex and generates a need for outcome indicators that summarize AMR for multiple antimicrobial classes. Model‐based clustering is a data‐driven approach that can help to objectively summarize AMR in animal reservoirs. In this study, a model‐based cluster analysis was carried out on a dataset of minimum inhibitory concentrations (MIC), recoded to binary variables, for 10 antimicrobials of commensal E. coli isolates (N = 12,986) derived from four animal species (broilers, pigs, veal calves and dairy cows) in Dutch AMR monitoring, 2007–2018. This analysis revealed four clusters in commensal E. coli in livestock containing 201 unique resistance combinations. The prevalence of these combinations and clusters differs between animal species. Our results indicate that to monitor different animal populations, more than one indicator for multidrug resistance seems necessary. We show how these clusters summarize multidrug resistance and have potential as monitoring outcome indicators to benchmark and prioritize AMR problems in livestock.
Zoonotic infection by Cryptosporidium fayeri IVgA10G1T1R1 in a Western Australian human
Authors: Braima Kamil , Zahedi Alireza , Oskam Charlotte , Austen Jill , Egan Siobhon , Reid Simon , Ryan Una
Published: January 2021

In the present study, a 37‐year‐old immunosuppressed female in Western Australia (WA) was identified as positive for Cryptosporidium by microscopy and treated with nitazoxanide. Molecular analyses at the 18S ribosomal RNA (18S) and 60 kDa glycoprotein (gp60) loci identified C. fayeri subtype IVgA10G1T1R1, which had previously been identified in western grey kangaroos (Macropus fuliginosus) in WA. Next generation sequencing (NGS) of the gp60 locus confirmed the absence of mixed infections with other Cryptosporidium species. This is only the second report of C. fayeri in a human host highlighting the zoonotic potential of this wildlife‐associated species. Routine diagnosis using molecular methods in laboratories is required to better understand the diversity and epidemiology of Cryptosporidium parasite.
A Minimum Creep Rate for 2-1/4Cr-1Mo Steel Consistent With the ASME Section III, Division 5 Rules
Authors: Chakraborty Aritra , Messner Mark C. , Sham T.-L.
Published: January 2021

This technical note describes a minimum creep rate model for 2-1/4Cr-1Mo steel that is consistent with the current creep strain equation embedded in the ASME Boiler & Pressure Vessel Code Section III, Division 5, Subsection HB, Subpart B isochronous stress–strain curves. Minimum creep rate models for all the Section III, Division 5 Class A materials are required for the development of improved high temperature design methods. Of all the Class A materials, only 2-1/4Cr-1Mo does not have a readily identifying minimum creep rate term in the current isochronous stress–strain curve model.
High-Fidelity Computational Fluid Dynamics Modeling and Analysis of a Pressure Vessel-Pipe-Safety Valve System in Gas Service
Authors: Zong Chaoyong , Zheng Fengjie , Dempster William , Chen Dianjing , Song Xueguan
Published: January 2021

A pressurized vessel-pipe-safety valve (PVPSV) system is a common configuration for many energy management systems, and a better understanding of their dynamics is helpful for system design and optimization. In this paper, a method for high-fidelity computational fluid dynamics (CFD) modeling is presented, which can be used to predict dynamic responses of PVPSV systems. For modeling, regions from the vessel outlet to the safety valve exit flange are modeled using a CFD approach; the pressure vessel is set as the boundary and the movement of the valve disk is represented by a one-dimensional (1D) rigid body motion model. Simulations are performed, and both stable and unstable operation are investigated. To establish accuracy, an experimental test rig is designed and constructed to measure the motion of the valve disk and the pressures at different system locations. Comparisons are performed for different dynamic modes and good agreement is obtained, supporting the accuracy of the high-fidelity model in reproducing the dynamic response of PVPSV systems. With the developed model, influences of other variables, such as piping length and safety valve configurations, can also be evaluated. The method presented in this paper can also be used to develop CFD models for other similar systems and should facilitate system design and optimization.
On the Material Properties for Piping Load and Resistance Factor Design
Authors: Avrithi Kleio
Published: January 2021

The probabilistic properties of steel, namely, the mean value, coefficient of variation, and probability distribution are needed for the development of Load and Resistance Factor Design (LRFD) equations for Class 2 and 3 nuclear piping and for probabilistic and risk analysis studies. This work investigates the probabilistic properties for the most representative steels used for nuclear piping, such as carbon, stainless austenitic, and low alloy. Steel properties at room temperature and up to temperature 700 °F are examined through reported mechanical behavior. The work concludes with the impact of the stainless steels' probabilistic properties on the reliability index or else probability of failure for the piping. The presented data can help organize steel materials for LRFD and reduce the variability of the reliability index.
Determination Method of Elasto-Plastic Correction Factor of TA16 Titanium Alloy Based on RCC-M Code Methodology
Authors: Shao Xuejiao , Du Juan , Zhang Liping , Xie Hai , Tian Jun , Shi Kaikai , Zhang Ying , Liu Zhenyu
Published: January 2021

In the code for nuclear equipment, the elasto-plastic correction factor KE is a correction factor when the stress range exceeds the yield limit for simplified elasto-plastic fatigue analysis. The parameters and expressions of KE for commonly used materials (such as austenitic stainless steel) are given in the RCC-M and ASME codes, but the parameters of KE for titanium alloy materials are lacking. Based on the cyclic elasto-plastic constitutive model of Z2CND18.12 (nitrogen control) and KE parameters of austenitic stainless steel given in the code, considering various sensitive factors, a numerical calculation method for determining KE correlation coefficient is established. The elasto-plastic constitutive model of TA16 alloy with nonlinear kinematic hardening was established by the uniaxial tension, strain, and stress cycling tests of TA16 titanium alloy. Based on the numerical calculation method of KE and the constitutive model of TA16 titanium alloy, the expression and correlation coefficient of KE for TA16 titanium alloy were determined.
Study on the Four-Quadrant Homologous Characteristic and Two-Phase Flow Head Degradation of a Reactor Coolant Pump
Authors: Huang Bin , Zhang Meimei , Pu Kexin , Wu Peng , Wu Dazhuan
Published: January 2021

This paper studies the four-quadrant homologous characteristic and analyzes the gas–liquid two-phase flow head degradation of ACP100 reactor coolant pump. The theoretical basis and the operating conditions of the pump's four-quadrant homologous characteristic are introduced. To verify the reliability of the computational fluid dynamics (CFD), the comparison of the results from CFD and test is implemented, and with these datum for the pump is plotted with homologous curves. In this paper, homologous pump characteristics are used to make the proper estimation on complete characteristic outside the testing range. Meanwhile, a combined method of impeller Euler head distribution and entropy generation rate analysis are applied for the head degradation of ACP100 reactor coolant pump under gas–liquid two-phase flow condition, and 70% of gas void fraction (GVF) is shown as the maximum degradation point. In addition, head degradation multiplier plots homologous curves are used to predict the homologous characteristic of specific GVF.
A Systematic Methodology to Assess Hydraulic Reliability and Gas Supply Reliability of the Natural Gas Pipeline Network
Authors: Yu Weichao , Gong Jing , Huang Weihe , Liu Hongfei , Dang Fuhua , Luo Jili , Sun Yuanhang
Published: January 2021

Reliability of the natural gas pipeline network is related to security of gas supply directly. According to the different required functions of the natural gas pipeline network, its reliability is divided into three aspects, namely mechanical reliability, hydraulic reliability, and gas supply reliability. However, most of the previous studies confused the definitions of the hydraulic reliability and gas supply reliability. Moreover, the uncertainty in the process of supplying natural gas to the targeted market and the hydraulic characteristic of the natural gas pipeline network are often ignored. Therefore, a methodology to assess hydraulic reliability and gas supply reliability of the natural gas pipeline network is developed in the study, and the uncertainty and hydraulic characteristic of the natural gas pipeline network are both considered. The methodology consists of four parts: establishment of the indicator system, calculation of the gas supply, prediction of the market demand, and assessment of the hydraulic reliability and gas supply reliability. Moreover, a case study is applied to confirm the feasibility of the methodology, and the reliability evaluation results provide a comprehensive picture about the abilities of the natural gas pipeline network to perform the specified gas supply function and satisfy consumers' demand, respectively. Furthermore, a comparison between these two types of reliability is presented. The results indicate that the natural gas pipeline network may not be able to meet the market demand even if the system completes the required gas supply tasks due to the impact of the market demand uncertainty.
Stress–Strain Assessments for Buried Oil Pipelines Under Freeze-Thaw Cyclic Conditions
Authors: Teng Zhen-Chao , Liu Xiao-Yan , Liu Yu , Zhao Yu-Xiang , Liu Kai-Qi , Teng Yun-Chao
Published: January 2021

In this study, outdoor freeze-thaw cyclic tests on the Q345 steel pipeline portion were conducted to analyze the buried oil pipeline stress evolution in a seasonally frozen soil area, namely, the Mohe–Daqing portion of China–Russia crude oil pipeline. The results obtained show that under the freeze-thaw cycle, the variation trend of soil temperature around the pipeline exhibited a hysteresis pattern, which was similar to that of atmospheric temperatures. The soil frost heaving force was shown to drop with depth, and its value at the pipe top was higher than that at the pipe bottom. With the number of freeze-thaw cycles, the frost heaving force of the soil first increased and finally stabilized, while the principal stress of the pipeline increased gradually, and its extreme value tended to be stable after 7–8 cycles, which was consistent with the “ratchet effect” theory. The above findings made it possible to elaborate on a more efficient freeze-thaw cyclic test setup for clarifying the mechanism of frozen soil/pipeline interactions.
Impact Pressure Evaluation of Water Jet Peening on Typical Concave Surfaces: Theoretical and Finite Element Analysis
Authors: Zhao Shusen , He Zhanshu , Li Yanmin
Published: January 2021

Water jet peening (WJP), a surface modification technique, can use the impact pressure induced by shock waves to introduce compressive residual stress in the surface of metal parts, thereby improving the fatigue life of metal parts, especially has broad application prospects in strengthening the concave surface area of metal parts. The impact pressure of the concave surface is different compared with the flat surface due to the effects of geometrical factors on the shock wave released. In this work, a mathematical model for calculating the peak pressure in the initial contact area of the concave surface is developed, and the effects of geometric factors (opening angle of V surface α and spherical radius R) and WJP parameters (jet velocity v and jet diameter d) on the peak pressure are analyzed by using finite element simulation models of WJP on concave V-shaped surface, concave spherical surface, V-groove surface, spherical groove surface, and spherical groove surface established with the coupled Eulerian–Lagrangian (CEL) algorithm of abaqus. A mechanism of impact pressure evaluation of the concave surface is developed to explain the peak pressure results obtained from finite element models. The results show that the peak pressure is mainly determined by α and v, while d does not affect the peak pressure for a concave V-shaped or V-groove surface. The peak pressure is mainly determined by R, v, and d for a concave spherical or spherical groove surface.
Energy Well: Concept of 20 MW Microreactor Cooled by Molten Salts
Authors: Ruščák Marek , Melichar Tomáš , Syblík Jan , Frýbort Otakar , Harut David , Losa Evžen , Mareček Martin , Mazzini Guido , Reungoat Mathieu , Pilát Jan , Benčik Marek , Král Pavel
Published: January 2021

In this paper is described the concept of a 20 MW microreactor cooled by molten salts with the registered trademark of Energy Well. Energy Well reactor is designed to supply either electricity or heat, in remote areas or into populated areas. The description includes context, main design features, safety systems, thermohydraulic analysis in RELAPS 3D, logistic, and transport of the reactor.
The Use of Polycarbonate as Dosimeter of High Doses
Authors: Zoul David , Koplová Markéta , Rosnecký Vít , Košťál Michal , Vinš Miroslav , Šimon Jan , Schulc Martin , Cabalka Martin , Kučera Jan , Strunga Vladimír
Published: January 2021

Dosimetry of high doses of ionizing radiation is a method widely used not only in the field of basic and applied research but also in various industries. High-dose irradiation is used in the sterilization of foodstuffs and prolongation of their shelf life, sterilization of tools, materials and wastewater, treatment of antiquities attacked by woodworm organisms, biological and genetic research, inhibition of seed germination, and retardation of fruit ripening. Furthermore, it has been applied in radiation resistance testing of materials, defectoscopy, industrial irradiation of materials (e.g., crosslinking and grafting of polymers or gemstone coloring by ionizing radiation), and last but not least, of course, nuclear energetics. In this work, the dosimetric properties of polycarbonate are studied. They are compared with a standardized and certified method using alanine dosimeters. In the case of gammas, the testing was realized for 60Co and neutron radiation was studied in the light water research nuclear reactor (LVR-15).
Comparison of Corrosion Behavior of the Austenitic Stainless Steel 316 L in Static and Flowing Liquid Lead
Authors: Rozumová Lucia , Košek Lukáš , Vít Jan , Hojná Anna , Halodová Patricie
Published: January 2021

Development of liquid lead cooled nuclear systems requires consideration of compatibility issues with the construction materials. In order to understand the corrosion or passivation behavior of the 316 L austenitic stainless steel, the steel specimens were exposed for 1000 h in liquid lead with 1 × 10−7 wt % oxygen level at 480 °C in static and flowing (velocity 1.6 m/s) conditions. Post-test microscopy investigation using scanning electron microscope with focused ion beam (FIB) was performed and it demonstrated significant differences in the formation of thin oxide layers in the two conditions. Maximum oxide thickness was 2 μm in the static lead (Pb) and less than 0.1 μm in the flowing Pb. In the static condition, oxide scale was not continuous and local corrosion attack was indicated; but in flowing condition the oxide layer was continuous without any corrosion attacks.
Metallic Fast Reactor Separate Effect Studies for Fuel Safety
Authors: Di Lemma Fidelma G. , Jensen Colby B. , Kane Joshua J. , Chen Wei-Ying , Liu Xiang , Capriotti Luca , Adkins Cynthia A. , Kombaiah Boopathy , Winston Alexander J. , He Lingfeng , Wachs Daniel
Published: January 2021

Sodium-cooled Fast Reactors (SFR) are one of the advanced nuclear reactor concepts to be commercially applied for electricity production. The benefits of SFR are well-known and include: the possibility of a closed fuel cycle, proliferation resistance, nuclear waste minimization via actinides burning, and fissile breeding capabilities. Metallic fuel used in SFR has well demonstrated irradiation performance. However, more studies are necessary to optimize and extend operational and safety limits for their commercialization and licensing. This could be achieved through a better understanding of fuel behaviors during transient and of fuel failure thresholds. This paper describes the experimental Research and Development (R&D) program aimed at providing the necessary data to support the development of SFR-optimized safety limits. This program integrates separate effects testing and integral effects testing, combined with advanced Modeling and Simulation (M&S). This R&D program, finally, focuses on delivering the science-based information necessary for supporting the licensing and utilization of SFR based on metallic fuel. In this paper we will describe the three research areas centered on fuel development and focused on separate effect testing, namely: (1) microstructural, chemistry, and material properties; (2) thermo-mechanical behavior; and (3) source term and fission product behavior. Preliminary results from these Separate Effect Tests (SET) studies and the current instruments and experimental plan are also presented.
Developing and Implementing Artificial Intelligence-Based Classifier for Requirements Engineering
Authors: Myllynen Santeri , Suominen Ilpo , Raunio Tapani , Karell Rasmus , Lahtinen Jussi
Published: January 2021

In nuclear power plant (NPP) projects, requirements engineering manages the sheer volume of requirements, typically characterized by descriptive and nonharmonized requirements. Large projects may have tens of thousands to hundreds of thousands of requirements to be managed and fulfilled. Two main issues impede requirements analysis: tortuous requirements to be interpreted; and humans' very limited ability to concentrate on a specific task. It has therefore been recognized that artificial intelligence (AI) algorithms have the potential to support designers' decision making in classifying and allocating NPP requirements into predefined classes. This paper presents our work on developing an AI-based requirements classifier utilizing natural language processing (NLP) and supervised machine-learning (ML). In addition, the paper presents the integration of the classifier with the requirements management system. The focus is on the classification of nuclear power industry-specific requirements utilizing deep-learning-based NLP. Three classifiers are compared, and the corresponding results are presented. The results include predetermined requirement classes, manually gathered and classified data, a comparison of three models and their classification accuracies, microservice system architecture, and integration of the established classifier with the requirements management system. As the performance of the requirements classifier and related system has been successfully demonstrated, future AI-specific development and studies are suggested to focus on atomizing multiclass requirements, combining similar requirements into one, checking requirements syntax, and utilizing unsupervised learning for clustering. Furthermore, new and advantageous requirement classes and hierarchies are suggested for development while improving current datasets both quantitatively and qualitatively.
Neutron Field Shaping Using Graphite for Reaction Rate Measurements
Authors: Sobaleu Mikita , Košťál Michal , Šimon Jan , Losa Evžen
Published: January 2021

Neutron field shaping is the suitable method for validation of cross section in various energy regions. By increasing the share of neutrons of a certain energy interval and decreasing the share of other, a reaction becomes more sensitive to selected neutrons. As a result, reaction cross section can be validated in selected energy regions more precisely. The shaping can be carried out by both neutron filters which are materials with high absorption in some energy region, or by diffusion material changing the shape of neutron spectra by means of slowing down process. In the presented experiments, the neutron field of the light reactor 0 (LR-0) research reactor was shaped by both using graphite blocks inserted into the core and Cd cladding for increasing the epithermal reaction rate share in total reaction rates. The calculations were carried out with the Monte Carlo N-Particle Transport Code 6 (MCNP6) code and the most recent nuclear data libraries. The results in the pure graphite neutron field are in good agreement; in case of Cd cladding, significant discrepancies were reported. In case of the 23Na(n,γ)24Na reaction, overestimation by about 14% was reached in International Reactor Dosimetry and Fusion File (IRDFF-II), results in other libraries are comparable. In case of 58Fe(n,γ)59Fe, the overestimation as high as 18% is reported in IRDFF-II. For 64Zn(n,γ)65Zn reasonable agreement was reached in evaluated nuclear data file (ENDF/B-VIII), where discrepancies in pure graphite neutron field or in case of Cd cladding are about 10–15%.
Build Up and Characterization of Ultraslow Nuclear Burn-Up Wave in Epithermal Neutron Multiplying Medium
Authors: Ray D. , Saraswat S. P. , Kumar M. , Singh O. P. , Munshi P.
Published: January 2021

A study is carried out on the build-up and characterization of ultraslow nuclear burn-up wave in epithermal neutron multiplying medium for slab geometry. Uranium-plutonium fissile medium is considered for the calculation. Transient part of the wave is characterized by transient time (TT), transient length (TL), and TT and TL are defined as the time and distance required to develop asymptotic neutron flux propagating through the media. Steady-state part of the wave is characterized with wave velocity and reaction zone width (full width half maximum (FWHM) and full width 10% of maximum (FW10M)). Parametric studies are carried out for different enrichment of 235U and different values of external source of neutron. It is observed that TT, TL, FWHM, and FW10M decrease with the increase in enrichment. The velocity of the wave increases with the enrichment of 235U. This study is beneficial for understanding the characteristics of nuclear burn-up wave in epithermal region as it will help in further researches in this area.
Actinide in Air (Rn-Progeny Rejected) Alpha Spectroscopy With Tensioned Metastable Fluid Detectors
Authors: Hemesath M. , Boyle N. , Archambault B. , Troy Lorier C. , DiPrete D. , Taleyarkhan R. P.
Published: January 2021

This article discusses outcome of research for deriving a methodology and apparatus for ascertaining for the presence of ultratrace-level actinides in air from their alpha emission signatures, while remaining blind to the relatively large (1000× higher activity) alpha emissions from Rn-progeny. Apparatus and techniques were developed to collect and characterize alpha-emitting nuclides of Rn-progeny and actinides in air on a polycarbonate 3 μm pore size continuous air monitor (CAM) filter. A wet-chemistry approach was developed and validated for successfully separating the Rn-progeny alpha emitting isotopes of Po-214 and Po-218, while extracting the actinides (U, Pu, Am) in a fluid mixture that is suitable for conduct of alpha spectroscopy with a centrifugally tensioned metastable fluid detector (CTMFD). The resulting α-TMFD technology was compared against the state-of-art “Alpha-Sentry™” Continuous Air Monitor (CAM) system commonly utilized world-wide. Results indicate that the α-TMFD technology can potentially offer complementary and superior performance in multiple performance categories, and ∼18× improvement in the time to detect (e.g., at 0.02 derived air concentration (DAC) within ∼3 h, versus ∼70 h for Alpha-Sentry) for actinides of interest while also remaining ∼100% blind to ∼103× higher Rn-progeny background—with the added potential for offering few keV scale energy resolution without resorting to peak shape fitting, versus ∼300–400 keV for existing CAM systems.
Online Spark Timing Optimization With Complex High-Fidelity Combustion Phasing, Knock, and Coefficient of Variation of IMEP Models
Authors: Zhu Qilun , Prucka Robert , Wang Shu , Prucka Michael
Published: January 2021

The combustion phasing of spark ignition (SI) engines is traditionally regulated with map-based spark timing (SPKT) control. The calibration of these maps is time-consuming for SI engines with a high number of control actuators. This paper proposes three online SPKT optimization algorithms that can utilize control-oriented semiphysics-based combustion models making the SPKT control algorithm more adaptive to different engine designs. These three SPKT optimizers do not require model inversion and derivative information. These methods also preserve the dependence between combustion phasing, knock, and coefficient of variation (COV) of indicated mean effective pressure (IMEP) models to avoid evaluating combustion models multiple times within one iteration. The two-phase and constraint relaxation methods are derived from direct search optimization theories. The recursive least square (RLS) polynomial fitting method can be considered as a virtual extreme seeking (ES) process that converts the original “black” box nonlinear constrained optimization into the solution of three low-order polynomial equations. Although these three online SPKT optimization approaches have unique properties making them preferable with certain types of combustion models, simulation and test results show that all of them can find the optimal SPKT with less than 10 evaluations of the combustion models. This fact makes it possible to implement the proposed model-based SPKT control strategy in future engine control units (ECUs).
Novel Integrated Active and Passive Control of Fluid-Borne Noise in Hydraulic Systems
Authors: Pan Min , Yuan Chenggang , Ding Beichen , Plummer Andrew
Published: January 2021

Fluid-borne noise (FBN) is a major contributor to structure-borne noise (SBN) and air-borne noise (ABN) in hydraulic fluid power systems and could lead to increased fatigue in system components. FBN is caused by the unsteady flow generated by pumps and motors and propagates through the system resulting in SBN and ABN. New hydraulic technologies such as digital switched hydraulic converters are also barriered by the unavoidable FBN. This article reports on a novel integrated FBN attenuation approach, which employs a hybrid control system by integrating an active feedforward noise attenuator with passive tuned flexible hoses. The active system which consists of adaptive notch filters using a variable step-size filtered-X Least Mean Squares algorithm is used to control a newly designed high-force high-bandwidth piezo-electric actuator in order to attenuate the dominant narrowband pressure ripples. The passive hose is tuned in the frequency domain and used to cancel the high-frequency pressure ripples. A time-domain hose model considering coupling of longitudinal wall and fluid waves was used to model the flexible hose in the integrated control system. Very good FBN cancelation was achieved by using the proposed integrated control approach both in simulation and experiments. It can be concluded that the active attenuator with passive flexible hoses can form an effective, cost-efficient and practical solution for FBN attenuation. The problem of high noise levels generated by hydraulically powered machines has risen significantly in awareness within industry and amongst the general public, and this work constitutes an important contribution to the sustainable development of low noise hydraulic fluid power machines.
Gas Supply Reliability Analysis of a Natural Gas Pipeline System Considering the Effects of Demand Side Management
Authors: Li Yichen , Gong Jing , Yu Weichao , Huang Weihe , Wen Kai
Published: January 2021

At present, China has a developing natural gas market, and ensuring the security of gas supply is an issue of high concern. Gas supply reliability, the natural gas pipeline system's ability to satisfy the market demand, is determined by both supply side and demand side and is usually adopted by the researches to measure the security of gas supply. In the previous study, the demand side is usually simplified by using load duration curve (LDC) to describe the demand, which neglects the effect of demand side management. The simplification leads to the inaccurate and unreasonable assessment of the gas supply reliability, especially in high-demand situation. To overcome this deficiency and achieve a more reasonable result of gas supply reliability, this paper extends the previous study on demand side by proposing a novel method of management on natural gas demand side, and the effects of demand side management on gas supply reliability is analyzed. The management includes natural gas prediction models for different types of users, the user classification rule, and the demand adjustment model based on user classification. First, an autoregressive integrated moving average (ARIMA) model and a support vector machine (SVM) model are applied to predict the natural gas demand for different types of users, such as urban gas distributor (including residential customer, commercial customer, small industrial customer), power plant, large industrial customer, and compressed natural gas (CNG) station. Then, the user classification rule is built based on users' attribute and impact of supplied gas's interruption or reduction. Natural gas users are classified into four levels. (1) demand fully satisfied, (2) demand slightly reduced, (3) demand reduced, and (4) demand interrupted. The user classification rule also provides the demand reduction range of different users. Moreover, the optimization model of demand adjustment is built, and the objective of the model is to maximize the amount of gas supplied to each user based on the classification rule. The constraints of the model are determined by the classification rule, including the demand reduction range of different users. Finally, the improved method of gas supply reliability assessment is developed and is applied to the case study of our previous study derived from a realistic natural gas pipeline system operated by PetroChina to analyze the effects of demand side management on natural gas pipeline system's gas supply reliability.
Correlation of Computational Instantaneous Wave-Free Ratio With Fractional Flow Reserve for Intermediate Multivessel Coronary Disease
Authors: Ghorbanniahassankiadeh Arash , Marks David S. , LaDisa John F.
Published: January 2021

This study computationally assesses the accuracy of an instantaneous wave-free ratio (iFR) threshold range compared to standard modalities such as fractional flow reserve (FFR) and coronary flow reserve (CFR) for multiple intermediate lesions near the left main (LM) coronary bifurcation. iFR is an adenosine-independent index encouraged for assessment of coronary artery disease (CAD), but different thresholds are debated. This becomes particularly challenging in cases of multivessel disease when sensitivity to downstream lesions is unclear. Idealized LM coronary arteries with 34 different intermediate stenoses were created and categorized (Medina) as single and multiple lesion groups. Computational fluid dynamics modeling was performed with physiologic boundary conditions using an open-source software (simvascular1) to solve the time-dependent Navier–Stokes equations. A strong linear relationship between iFR and FFR was observed among studied models, indicating computational iFR values of 0.92 and 0.93 are statistically equivalent to an FFR of 0.80 in single and multiple lesion groups, respectively. At the clinical FFR value (i.e., 0.8), a triple-lesion group had smaller CFR compared to the single and double lesion groups (e.g., triple = 3.077 versus single = 3.133 and double = 3.132). In general, the effect of additional intermediate downstream lesions (minimum lumen area > 3 mm2) was not statistically significant for iFR and CFR. A computational iFR of 0.92 best predicts an FFR of 0.80 and may be recommended as threshold criteria for computational assessment of LM stenosis following additional validation using patient-specific models.
Effects of External Load on Sagittal and Frontal Plane Lower Extremity Biomechanics During Back Squats
Authors: Maddox Eva U. , Bennett Hunter J.
Published: January 2021

Previous literature suggests the sticking region, the transition period between an early peak concentric velocity to a local minimum, in barbell movements may be the reason for failing repeated submaximal and maximal squats. This study determined the effects of load on lower extremity biomechanics during back squats. Twenty participants performed the NSCA's one-repetition-maximum (1RM) testing protocol, testing to supramaximum loads (failure). After completing the protocol and a 10-min rest, 80% 1RM squats were performed. Statistical parametric mapping (SPM) was used to determine vertical velocity, acceleration, ankle, knee, and hip sagittal and frontal plane biomechanics differences between 1RM, submaximum, and supramaximum squats (105% 1RM). Vertical acceleration was a better discriminative measure than velocity, exhibiting differences across all conditions. Supramaximum squats emphasized knee moments, whereas 1RM emphasized hip moments during acceleration. Submaximum squats had reduced hip and knee moments compared to supramaximum squats, but similar knee moments to 1RM squats. Across all conditions, knee loads mirrored accelerations and a prominent knee (acceleration) to hip (sticking) transition existed. These results indicate that (1) submaximum squats performed at increased velocities can provide similar moments at the ankle and knee, but not hip, as maximal loads and (2) significant emphasis on hip strength is necessary for heavy back squats.
Total Least-Squares Determination of Body Segment Attitude
Authors: Challis John H.
Published: January 2021

To examine segment and joint attitudes when using image-based motion capture, it is necessary to determine the rigid body transformation parameters from an inertial reference frame to a reference frame fixed in a body segment. Determine the rigid body transformation parameters must account for errors in the coordinates measured in both reference frames, a total least-squares problem. This study presents a new derivation that shows that a singular value decomposition-based method provides a total least-squares estimate of rigid body transformation parameters. The total least-squares method was compared with an algebraic method for determining rigid body attitude (TRIAD method). Two cases were examined: case 1 where the positions of a marker cluster contained noise after the transformation, and case 2 where the positions of a marker cluster contained noise both before and after the transformation. The white noise added to position data had a standard deviation from zero to 0.002 m, with 101 noise levels examined. For each noise level, 10 000 criterion attitude matrices were generated. Errors in estimating rigid body attitude were quantified by computing the angle, error angle, required to align the estimated rigid body attitude with the actual rigid body attitude. For both methods and cases, as the noise level increased the error angle increased, with errors larger for case 2 compared with case 1. The singular value decomposition (SVD)-based method was superior to the TRIAD algorithm for all noise levels and both cases, and provided a total least-squares estimate of body attitude.
Nuclear Power and Nuclear Technologies Can Benefit From Regional Implementation of Multinational Approaches
Authors: McCombie Charles
Published: January 2021

Nuclear energy is a proven low-carbon technology that can provide the dispatchable electricity needed to stabilize national grids that have increasing shares of renewables. Other nuclear technologies are applied in medicine, industry, and research to provide benefits to both developed and developing countries around the world. All nuclear applications result in the production of radioactive wastes. The safe and secure management and disposal of these wastes are essential for the use of these technologies to be sustainable. The expertise and the funding required must be available to all countries employing them. For some countries, this can be ensured more easily (or only) by implementation of multinational approaches. In particular, implementing geological disposal facilities (GDFs) for radioactive wastes presents a special challenge; these must be available to nuclear power countries, and they are also a necessity for nonnuclear power nations employing other technologies that produce small quantities of long-lived radioactive wastes. In all waste management programs, implementing a GDF is a challenging task requiring sensitive stakeholder interactions and significant funding. For small or new programs, the societal and economic challenges are both large. Multinational repositories (MNRs) — GDFs disposing of radioactive wastes from several countries — can provide a solution. This paper briefly illustrates nuclear technologies that give rise to radioactive wastes. It then reviews initiatives devoted to promoting multinational cooperation, and in particular in MNR developments, both globally and specifically in Europe. Several national programs have adopted the MNR concept as part of a so-called “dual track” approach in their national waste management strategy. An important recent organizational development is the transition of the European Repository Development Organization Working Group into a formal legal entity, the ERDO Association, with dedicated facilities and personnel. By supporting MNR development, we can work toward a world in which all countries can benefit from nuclear technologies, free from safety, security, or environmental concerns related to the disposal of their radioactive wastes.
Estimating Radon Excess Lung Cancer at the Babylon Cement Plant in Iraq
Authors: Ahmed Israa Kamil , Khalaf Hyam Nazmy Bader , Mostafa Mostafa Y. A.
Published: January 2021

In this work, radon excess lung cancer (ELC) was estimated for 14 soil samples from the Babylon cement plant in Iraq. A CR-39 nuclear track detector was used to measure uranium and radon (222Rn) concentrations in the soil samples. The uranium concentration varied from 0.008 to 0.05 ppm, with a mean value of 0.025 ± 0.013 ppm. The radon concentration was found to be between 31 and 92 Bq/m3, with a mean value of 56.72 and a standard division of 17.29. The radon ELC per million persons per year has a mean value of 863 (463.81–12,082.8) and a standard division of 261.65. The annual effective dose, E (mSv/y), ranged from 0.77 to 2.32, with a mean value of 1.44 and a standard division of 0.44.
The Environmental, Economic, and Social Performance of Nuclear Technology in Australia
Authors: Malatesta Troy
Published: January 2021

The prominence of climate change is surging with Australia feeling the impacts of hotter and dryer climates. With 2030 approaching, Australia's promise to reduce emissions is seeming harder to achieve with their energy mix being dominated by fossil fuels. The development of small modular reactor (SMR) technology in the nuclear industry offers a possible solution for Australia to shift away from coal and gas energy sources and invest in low carbon nuclear technologies. SMR technology is suitable for the Australian context due to the number of remote locations, the size of the mining, and processing industries and the minimal nuclear experience Australia has. This study aimed to quantify the environmental benefits of Australia incorporating nuclear power in their energy mix and to calculate the levelized cost of electricity of constructing a 684 MWel nuclear plant using the NuScale module. Additionally, a survey was created to provide an insight into the Australian perception of energy generation and nuclear power. The responses showed the Australian attitudes toward nuclear power and the misconceptions that are resulting in negative perceptions and attitudes.
Nonlinear Modal Analysis of Frictional Ring Damper for Compressor Blisk
Authors: Sun Yekai , Yuan Jie , Denimal Enora , Salles Loïc
Published: January 2021

The use of integrally blisk is becoming popular because of the advantages in aerodynamic efficiency and mass reduction. However, in an integrally blisk, the lack of the contact interface leads to a low structural damping compared to an assembled bladed disk. One emerging damping technique for the integrally blisk is based on the use of friction ring damper, which exploits the contact interfaces at the underneath of the disk. In this paper, three different geometries of the ring dampers are investigated for damping enhancement of a blisk. A full-scale compressor blisk is considered as a case study where a node-to-node contact model is used to compute the contact forces. The dynamic behavior of the blisk with the ring damper is investigated by using nonlinear modal analysis, which allows a direct estimation of the damping generated by the friction interface. The damping performance for the different ring dampers is evaluated and compared. It appears that the damping efficiency as well as the shift in the resonant frequency for the different geometries is highly related to the nodal diameter and contact pressure/gap distributed within contact interface. The geometry of the ring damper has significant impact on the damping performance.
Bayesian Machine Learning for the Prognosis of Combustion Instabilities From Noise
Authors: Sengupta Ushnish , Rasmussen Carl E. , Juniper Matthew P.
Published: January 2021

Experiments are performed on a turbulent swirling flame placed inside a vertical tube whose fundamental acoustic mode becomes unstable at higher powers and equivalence ratios. The power, equivalence ratio, fuel composition, and boundary condition of this tube are varied and, at each operating point, the combustion noise is recorded. In addition, short acoustic pulses at the fundamental frequency are supplied to the tube with a loudspeaker and the decay rates of subsequent acoustic oscillations are measured. This quantifies the linear stability of the system at every operating point. Using this data for training, we show that it is possible for a Bayesian ensemble of neural networks to predict the decay rate from a 300 ms sample of the (unpulsed) combustion noise and therefore forecast impending thermoacoustic instabilities. We also show that it is possible to recover the equivalence ratio and power of the flame from these noise snippets, confirming our hypothesis that combustion noise indeed provides a fingerprint of the combustor's internal state. Furthermore, the Bayesian nature of our algorithm enables principled estimates of uncertainty in our predictions, a reassuring feature that prevents it from making overconfident extrapolations. We use the techniques of permutation importance and integrated gradients to understand which features in the combustion noise spectra are crucial for accurate predictions and how they might influence the prediction. This study serves as a first step toward establishing interpretable and Bayesian machine learning techniques as tools to discover informative relationships in combustor data and thereby build trustworthy, robust, and reliable combustion diagnostics.