bluuebunny/crossref_metadata_2025_split huggingface dataset:
An investigation of shedding and super‐shedding of Shiga toxigenic Escherichia coli O157 and E. coli O26 in cattle presented for slaughter in the Republic of Ireland
Authors: McCabe Evonne , Burgess Catherine M. , Lawal Dolapo , Whyte Paul , Duffy Geraldine 
Published: October 2018

SummaryShiga toxigenic Escherichia coli (STEC) are an important group of pathogens and can be transmitted to humans from direct or indirect contact with cattle faeces. This study investigated the shedding of E. coli O157 and O26 in cattle at the time of slaughter and factors associated with super‐shedding (SS) animals. Rectoanal mucosal swab (RAMS) samples were collected from cattle (n = 1,317) at three large Irish commercial beef abattoirs over an 18 month period, and metadata were collected at the time of sampling regarding farm of origin, animal age, breed and gender. RAMS swabs were examined for the presence and numbers of E. coli O157 and O26 using a previously developed quantitative real‐time PCR protocol. Samples positive by PCR were culturally examined and isolates analysed for the presence of stx subtypes, eae and phylogroup. Any samples with counts >104 CFU/swab of STEC O157 or O26 were deemed to be super‐shedders. Overall, 4.18% (55/1,317) of RAMS samples were positive for STEC O157, and 2.13% (28/1,317) were classified as STEC O157 SS. For STEC O26, 0.76% (10/1,317) of cattle were positive for STEC O26, and 0.23% (3/1,317) were classified as super‐shedders. Fewer STEC shedders and SS were noted among older animals (>37 months). There was a seasonal trend observed for STEC O157, with the highest prevalence of shedding and SS events in the autumn (August to October). The majority of E. coli O157 (50/55) isolates had stx2 and were eae positive, with no significant difference between SS and low shedders (LS). Interestingly, all STEC O26 (n = 10) were eae negative and had varied stx profiles. This study demonstrates that, while the overall shedding rates are relatively low in cattle at slaughter, among positive animals there is a high level of SS, which may pose a higher risk of cross‐contamination during slaughter.
Developmental maturation of activity‐induced K+ and pH transients and the associated extracellular space dynamics in the rat hippocampus
Authors: Larsen Brian Roland , Stoica Anca , MacAulay Nanna 
Published: October 2018

Key points
Neuronal activity induces fluctuation in extracellular space volume, [K+]o and pHo, the management of which influences neuronal function
The neighbour astrocytes buffer the K+ and pH and swell during the process, causing shrinkage of the extracellular space
In the present study, we report the developmental rise of the homeostatic control of the extracellular space dynamics, for which regulation becomes tighter with maturation and thus is proposed to ensure efficient synaptic transmission in the mature animals
The extracellular space dynamics of volume, [K+]o and pHo evolve independently with developmental maturation and, although all of them are inextricably tied to neuronal activity, they do not couple directly.
AbstractNeuronal activity in the mammalian central nervous system associates with transient extracellular space (ECS) dynamics involving elevated K+ and pH and shrinkage of the ECS. These ECS properties affect membrane potentials, neurotransmitter concentrations and protein function and are thus anticipated to be under tight regulatory control. It remains unresolved to what extent these ECS dynamics are developmentally regulated as synaptic precision arises and whether they are directly or indirectly coupled. To resolve the development of homeostatic control of [K+]o, pH, and ECS and their interaction, we utilized ion‐sensitive microelectrodes in electrically stimulated rat hippocampal slices from rats of different developmental stages (postnatal days 3–28). With the employed stimulation paradigm, the stimulus‐evoked peak [K+]o and pHo transients were stable across age groups, until normalized to neuronal activity (field potential amplitude), in which case the K+ and pH shifted significantly more in the younger animals. By contrast, ECS dynamics increased with age until normalized to the field potential, and thus correlated with neuronal activity. With age, the animals not only managed the peak [K+]o better, but also displayed swifter post‐stimulus removal of [K+]o, in correlation with the increased expression of the α1‐3 isoforms of the Na+/K+‐ATPase, and a swifter return of ECS volume. The different ECS dynamics approached a near‐identical temporal pattern in the more mature animals. In conclusion, although these phenomena are inextricably tied to neuronal activity, our data suggest that they do not couple directly.
La incorporación y el aumento de oferta de alimentos industrializados en las dietas de las unidades domésticas y su relación con el abandono del sistema de subsistencia propio en las comunidades rurales mayas de Yucatán, México
Authors: Otero Prevost David Enrique , Gurri García Francisco Delfín , Mariaca Méndez Ramón , Guízar Vázquez Jr. Francisco 
Published: October 2018

El presente trabajo de investigación se dedica al estudio de la relación del abandono de la milpa, el sistema de subsistencia desarrollado alrededor del maíz como cultivo básico en Mesoamérica, con la oferta de alimentos industrializados. Así, se analiza cuál de esos factores es el responsable de la incorporación de alimentos de ese tipo a la dieta de las unidades domésticas rurales mayas de Yucatán, México. Mediante un análisis de varianza de dos vías se comparó la proporción de alimentos industrializados consumidos por unidades doméstica campesinas que hacían milpa con las que ya no la implementaban en comunidades 1 con diferente oferta de alimentos industrializados. Se encontró que, en relación con las unidades domésticas que ya no hacían milpa, las milperas consumían una menor proporción de alimentos industrializados, independientemente de la oferta que ofreciera su comunidad de residencia.
Hybrid Eulerian Multiphase-Dense Discrete Phase Model Approach for Numerical Simulation of Dense Particle-Laden Turbulent Flows Within Vertical Multi-Stage Cyclone Heat Exchanger
Authors: Cristea Eugen-Dan , Conti Pierangelo 
Published: October 2018

This article describes a CFD engineering application developed to investigate numerically the multiphase, non-isothermal, turbulent flow physics within the suspension preheater of a dry-process rotary cement kiln. The multi–stage cyclone preheater is a counter-current heat exchanger.
We used the CFD flow solver ANSYS-Fluent R18.1. to accomplish this task. The hybrid Eulerian multiphase-dense discrete phase model is a coupled Eulerian-Lagrangian technique. The primary carrier-phase is treated as a continuum by solving the Navier-Stokes equations, while the secondary discrete dispersed-phase is solved by tracking the particle parcels through the calculated flow field. The multiphase turbulence of the carrier-phase is modeled using the Reynolds stress transport model. The dispersed-phase interactions are modeled through the specific collisions models provided by the kinetic theory of granular flow and/or discrete element method. The Eulerian multiphase-DDPM method provided a quiet stable solution for a medium/high mass loading (solid to gas mass ratio 0.89:1).
The four-stage cyclone suspension preheater is analyzed for its operating performance i.e. overall pressure drop and global collection efficiency of cyclone stages, calcination degree at bottom cyclone stage, flue gas temperature at 1st. cyclone stage and availability to get more insight of very complex multi-phase flow patterns within this equipment. The set of industrial measurements, collected during a heat and mass balance of a dry process rotary cement kiln, were used to verify and to validate part of the simulation results.
Systematic Development and Mesh Sensitivity Analysis of a Mathematical Model for an Anode Baking Furnace
Authors: Nakate Prajakta , Lahaye Domenico , Vuik Cornelis , Talice Marco 
Published: October 2018

The anode baking process is developed and improved since the 1980s due to its importance in Aluminium industry. The process is characterized by multiple physical phenomena including turbulent flow, combustion process, conjugate heat transfer, and radiation. In order to obtain an efficient process with regards to quality of anodes, soot-free combustion, reduction of NOx and minimization of energy, a mathematical model can be developed. A mathematical model describes the physical phenomena and provides a deeper understanding of the process.
Turbulent flow is one of the important physical phenomena in an anode baking process. In the present work, isothermal turbulent flow is studied in detail with respect to two turbulence models in COMSOL Multiphysics software. The difference between wall boundary conditions for these models and their sensitivity towards the boundary layer mesh is investigated. A dimen-sionless distance in viscous scale units is used as a parameter for comparison of models with and without a boundary layer mesh. The investigation suggests that the boundary layer mesh for both turbulence models increase the accuracy of flow field near walls. Moreover, it is observed that along with the accuracy, the numerical convergence of Spalart-Allmaras turbulence model in COMSOL Multiphysics is highly sensitive to the boundary layer mesh. Therefore, development of converged Spalart-Allmaras model for the complete geometry is difficult due to the necessity of refined mesh. Whereas, the numerical convergence of k-ε model in COMSOL Multiphysics is less sensitive to the dimen-sionless viscous scale unit distance. A converged solution of the complete geometry k-ε model is feasible to obtain even with less refined mesh at the boundary. However, a comparison of a developed solution of k-ε model with another simulation environment indicates differences which enhance the requirement of having converged Spalart-Allmaras model for complete geometry.
Turbulent Flow Characteristics Over Offset Wall Confined Columns in a Channel at Low Reynolds Numbers
Authors: Toxopeus Kira , Siddiqui Kamran 
Published: October 2018

The current study is focused on the flow through offset, wall confined vertical inserts in a channel. The columns are intended to act as the thermal storage media, which continuously exchange heat with the channel fluid to regulate it thermally. These columns could, for example, be filled with a phase change material (PCM) for passive thermal regulation, or have hot or cold fluid pumped through them for active thermal regulation. The current study has two parts: (1) the flow characterization without heat transfer, and (2) flow characterization during thermal exchange with a PCM used for regulation of bulk fluid temperature. The work presented here is focused only on the first part of the study.
The experiments were conducted in a narrow channel, with water as the working fluid. Two geometries of the vertical columns (circular and square) and two offset lengths were considered. For each configuration, experiments were conducted at Reynolds numbers of 20, 50 and 90 (based of the column’s characteristic length). Particle image velocimetry was used to measure the two-dimensional velocity field in a horizontal plane at multiple regions of interest along the length of the channel to characterize the flow passing over columns. The results indicate vortex shedding at the two higher Reynolds numbers. The generation, magnitude and decay rate of turbulent energy is shown to have an offset dependency at Re = 90, but a column shape dependency at Re = 50. The mean flow has a shape dependency due to the difference in separation point over the square and circular columns.
The Effects of Compressibility and Piping Geometry on Steamhammer Loads
Authors: Moody Frederick J. , Stakenborghs Robert 
Published: October 2018

Nuclear power plants typically consider a turbine trip and rapid closure of the main turbine stop valves as a normal transient event. As required by ASME Code [1], the piping loads generated by the unbalanced pressures in the system resulting from the rapid valve closure are part of the analyzed spectrum of conditions in the piping and support analysis. The analysis that determines the magnitude and timing of the loads is often referred to as a “steamhammer” analysis.
Currently, there are several computerized analytical techniques to determine the steamhammer piping and support loads [2], but because of compressibility assumptions the equations become more difficult to solve than in the analogous incompressible waterhammer models, which are quite straightforward.
This paper highlights the effect of fluid compressibility by comparing results predicted by both waterhammer (slightly compressible) flow models and compressible (steamhammer) flow models. Guidelines are offered to show how parameters of a piping system (such as pipe length, valve closure time and flow characteristic, steam initial state properties, and velocity) can be interpreted to determine if compressible effects are insignificant or if they play a significant role.
Study on Emergency Planning Zone Determination for CAP200 Small Modular Reactor
Authors: Xuan Wang , Fenglei Du , Dawei Sun , Te Tang 
Published: October 2018

Determination of the SMR emergency planning zone (EPZ) is one of the important external constraint factor of its marketing and application, which means that it is very important to formulate appropriate classification criteria and establish proper size range.
In China, due to the requirement of “Criteria for emergency planning and preparedness for nuclear power plants: Part 1, The dividing of emergency planning zone.” (GB/T 17680.1-2008), for PWR nuclear power plant, its external plume EPZ should be within 7km–10km, and its internal plume EPZ should be within 3km∼5km. However, the scope of the standard for the emergency planning area is currently limited to conventional nuclear power plants, and for the current SMR, its emergency planning size is not included.
In this paper, we will analyze the classification method of SMR EPZ based on the traditional Nuclear Power Plants feedback experience, including selection of source term, accident cutoff probability, determination method of the plume EPZ and the ingestion EPZ. Three typical nuclear power plant sites in China are chosen as CAP200 case study sites, including two inland nuclear power plant sites and one coastal site. The three sites can represent most of the meteorological and terrain characters of China nuclear power plants.
According to the CAP200 source term and meteorological data of the sites, MACCS2 computer program is used to calculate the severe accidents consequence. Conclusions show that for the CAP200 SMR, the accident cutoff probability can be 1.0E−08 to 1.0E−07 per reactor per year, and its project dose exceeding probability in the three sites boundary is far below 30%, which directs that for CAP200 SMR, its plume and ingestion emergence planning zone is limited to the on-site area, and its off-site emergency response can be simplified.
Research Concept of Decommissioning Knowledge Management for the Fugen NPP
Authors: Taruta Yasuyoshi , Yanagihara Satoshi , Iguchi Yukihiro , Kitamura Koichi , Tezuka Masashi , Koda Yuya 
Published: October 2018

In 2002, the International Atomic Energy Agency (IAEA) mentioned the strengthening of nuclear knowledge, technology and application. This background has that there are aging of nuclear facility and nuclear power plant staffs. In addition, it would be difficult to succession a nuclear knowledge, technology, and skills. For example, undergraduate departments of nuclear energy and science are decreasing. The IAEA discussing those situations and pointed out the importance of a nuclear knowledge management. The nuclear knowledge management (NKM) is developing a database science as management on nuclear knowledge and information. In recent years, the IAEA has also advanced knowledge taxonomies on nuclear accidents as one of a nuclear knowledge management. In Japan, this achievements of nuclear knowledge taxonomy was using in the organization of information on accidents in Fukushima. A few studies are attempts to appropriately arrange and utilize huge amounts of information.
Even in nuclear facilities in Japan, it is pointed out a veteran or expert staff retirement and loss of knowledge and skill caused by this retirement. This problem is common issue in the world. Then, we created a prototype database system to utilize past documentation of knowledge and information. The database made from semantic web technology. The semantic web is a method of preparing a frame of categorized knowledge and linking information related to it. The target is a nuclear reactor of ATR Fugen that is decommissioning from 2008. Until now, cases of decommissioning completion are 17 cases in the world. One case of JPDR in Japan. It is not enough to understand a good method of decommissioning.
In general, the decommissioning project requires many information related to dismantling and decontamination. Particular, past information is important to know a past contamination situation and so on. This study focus on an access method for past data and information. However, we need to pay attention to other side of decommissioning project. Because of history of operating reactor has different tasks that are design, construction, operation and decommissioning. It is not appropriate to use the collected information as it is. For that reason, we will continue our research on the points pointed out above.
Numerical Investigation on the Characteristic of the Reverse Flow Phenomenon in a Z-Type Parallel Compact Heat Exchanger With Large Number of Tubes
Authors: Zhou Jian , Ding Ming , Bian Haozhi , Zhang Yinxing , Sun Zhongning 
Published: October 2018

The parallel compact heat exchangers have been widely applied in the various fields such as heat exchangers in chemical engineering, the solar collector, fuel cells and the passive removal heat exchanger in passive containment cooling system (PCCS), etc. The heat exchangers in the PCCS removes out the heat brought by the steam coming out from the broken reactor or primary cooling system. Therefore, the performance of the passive containment cooling system heat exchanger (PCCS HX) will greatly influence the safety and integrity of the containment. In previous investigations on the parallel compact heat exchangers, attentions are focused on the pressure distribution and flow distribution in the heat exchangers. A bad flow distribution in the heat exchanger will reduce the heat performance. More seriously, the coolant in some tubes may boils and the tubes will be overheated, resulting in explosion of tubes. Therefore, the characteristic of pressure distribution and the flow distribution should be investigated for a uniform flow distribution.
In the past studies of the compact heat exchangers, the numbers of tube are almost under 72 which is relatively small, while the number of tubes PCCS HX is usually over than 100. And the pressure distribution in compact heat exchangers is assumed that the pressure recovery plays a leading role.
However, the more numbers of tube will bring more flow maldistribution, if the geometry design is selected inappropriately. The reverse flow may occur in the heat exchanger, which means that in some tubes, the coolant flows from the tube outlet to the inlet. This phenomenon of reverse flow have never been mentioned in previous studies. The occurrence of the reverse flow will significantly decrease the performance of the heat exchanger and cause a bad influence on the safety of the containment.
In the PCCS, the Z-type heat exchanger is one of the choice of PCCS HX (heat exchanger) design. Therefore, the present study focus on the characteristic of reverse flow phenomenon in Z-type heat exchangers. The pressure distribution and the flow distribution have been separately investigated deeply. The conclusion of this study will provide a guide to the geometry design of the PCCS HX with large number of tubes.
On Experimental and Computational Investigation of Heat Transfer Deterioration and Hydraulic Resistance in Annular Channel and SCWR 3-Rod Bundle
Authors: Filonov Vladislav V. , Filonova Yuliia S. , Razumovskiy Victor G. , Pis'mennyi Evgeniy N. 
Published: October 2018

The experiments on upward flow of supercritical water in a vertical annuli and 3-rod tight bundle simulator made of 485-mm heated-length tubes of 5.2-mm OD and 4.5-mm ID with four helical ribs of 0.6-mm height, 1-mm width, and axial 400-mm pitch are presented.
Heat transfer and pressure drop under various operating conditions (inlet pressure and temperature, flow mass rate and heat flux) were investigated. Longitudinal wall temperature profiles made it possible to determine the place and flow thermal state of heat transfer deterioration (HTD) onset. Analysis of the obtained data (about 200 regimes) proved their good enough agreement with the correlations previously derived by the authors both for the heat flux rate (q/G)b of HTD beginning and for pressure drop in round tubes and annular channels. These correlations were updated to correct the results of their prediction.
Computational fluid dynamics and its counterpart computational heat transfer were used for modeling the above-mentioned thermohydraulic processes studied in the first part of the work by finding the most adequate flow turbulence model and optimized domain meshing. The accepted model was benchmarked by some data on heat transfer and pressure drop in tubes and annular channels cooled by SCW.