bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Prior Plastic Loading on the Accumulation of Creep Strain in 316H Stainless Steel
Authors: Taylor Megan , Mamun Abdullah al , Knowles David
Published: November 2019

Structural components are regularly exposed to cyclic thermal stresses which can induce plastic deformation within them. The accumulation of plastic deformation will eventually lead to failure of the component. The creep behaviour a material exhibits depends upon the magnitude and sign of the prior loading the material was subjected to. This idea was investigated by conducting tests on a section of 316H stainless steel header at 550°C. Both negative and positive plastic strain were applied upon loading followed by load controlled creep to investigate the influence of prior loading upon the accumulation of creep strain. These tests resulted in more creep strain being accumulated after compressive prior loading as opposed to tensile prior loading. This result is significantly influenced by intergranular strains which come from elastic and plastic anisotropy. The experimental results have been compared to the results of an existing crystal plasticity finite element (CPFE) model and there is good agreement between the two sets. Validation of the CPFE model is important for understanding the behaviour of 316H and being able to accurately predict the hysteresis loop this material produces which can provide vital information when conducting life assessments.
Design Methodologies for High Temperature Reactor Structural Components Cladded With Noncompliant Materials
Authors: Barua B. , Phan V.-T. , Messner M. C. , Jetter B. , Sham T.-L. , Wang Y.
Published: November 2019

The existing Class A metallic materials qualified for ASME Section III, Division 5 rules for high temperature nuclear reactors, are not optimized for corrosion resistance when exposed to corrosive reactor coolants such as molten salts, and molten lead and lead-bismuth eutectic. Introducing new corrosion-resistant materials into the Code would be a lengthy and expensive process for long design lifetimes, requiring long-term creep test data. A near-term alternative solution might be to allow designers to clad the existing Class A materials with thin layer of some corrosion-resistant material. However, the current ASME Section III, Division 5 rules provide no guidance on evaluating cladded components against the Code creep-fatigue or strain limits requirements. This necessitates the development of design rules for cladded components that do not require long-term testing of clad materials. Depending on the difference in mechanical properties, the influence of clad on the long term response of the structural system can be significant or negligible. This work focuses on developing design rules for cladded components with a clad material that does not accumulate significant inelastic deformation compared to the base material. This work proposes to treat such clad materials as linear elastic. Sample calculations including finite element analyses of a representative molten salt reactor heat exchanger tube without and with clad were performed to verify the proposed approach. Finally, a complete set of design rules for components with noncompliant clad material is proposed.
Crack Repair Using Hybrid Additive Manufacturing and Friction Stir Processing
Authors: Al-Badour Fadi , Zainelabdeen Ibrahim H. , Suleiman Rami K. , Adesina Akeem
Published: November 2019

A hybrid additive manufacturing (AM) and friction stir processing (FSP) was used to heal a crack in 6 mm thick Al 6061-T6 aluminum alloy. AL-6061 is usually used in H2 high-pressure vessel fabrication as well as aerospace applications. In this work, Al-Si powder was utilized to fill the crack, then FSP was applied to consolidate and stir the powder with the base metal to fill and close the crack zone. Effect of FSP parameters including welding speed and tool rotation speed on the quality of repair was studied. Various mechanical tests, as well as characterization techniques such as hardness test, optical microscopy, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS), were employed to study the newly developed hybrid process on the quality of the repair. The investigation revealed that low rotational speed of 800 rpm results in minimum variation in microhardness. Moreover, the impact of welding speed on microhardness is smaller as compared to rotational speed.
Deformation Behavior and J-Integral of Macroscopic Hydride Platelet Clusters in Hydrided Zr-2.5Nb Pressure Tube Materials Under Plane Strain Conditions
Authors: Wu Shengjia , Pan Jwo , Scarth Douglas A. , St. Lawrence Sterling
Published: November 2019

The mechanical behavior and J-integral of macroscopic hydride platelet clusters in hydrided Zr-2.5Nb pressure tube materials are investigated by two-dimensional finite element analyses with cohesive zone model under plane strain conditions. The hydride platelets are assumed to be separated at the early stage of the loading and are treated as cracks. The cohesive zone model with a trapezoidal traction-separation law is adopted. The macroscopic mechanical behavior is quantified by the macroscopic stress-strain relations and the fracture parameter of the bulk radial hydride is specified by the J integral-stress relations. The hydride platelet spacing has major effects while the cohesive energy and cohesive strength have minor effects on the mechanical behavior and fracture properties of the bulk hydrides. The computational results suggest that the hydride platelet cluster can be viewed as a soft region with a reduced load carrying capacity at large stress under plane strain loading conditions. A hydride platelet cluster may be treated as a cracked bulk hydride but with a reduced crack tip driving force for fracture.
Subsea Intervention System Connector Capacities per the Elastic-Plastic Analysis Methodology
Authors: Sepehri Ali , Bansal Gaurav , Edke Mangesh
Published: November 2019

The offshore oil and gas industry is drilling into and producing from wells in high-pressure, high-temperature (HPHT) environments. This has created a greater demand to develop more advanced tools and new technology to safely overcome the challenges in these operations. Due to the sensitivity and potential impact on the environment, the industry is striving to homogenize the design and acceptance criteria. The API 17G is the industry standard for offshore intervention operations. According to the standard, design verification is performed using finite element analysis (FEA). The standard provides three sets of criteria for determining capacities that adopt the methodologies from ASME Boiler Pressure Vessel Code (BPVC) Section VIII, Div. 3.

The objective of this study is to evaluate tension, pressure, and bending moment capacities per the elastic-plastic analysis methodologies outlined in API 17G for a subsea intervention system connector. The global and local failure capacities are presented for yielding load, plastic collapse, and 2% strain methods. Results indicate that the plastic collapse method is the most conservative approach for evaluating the global capacity of the connector.
Evaluating the Resistance of Austenitic Stainless Steel Welds to Hydrogen Embrittlement
Authors: Ronevich Joseph , San Marchi Chris , Balch Dorian K.
Published: November 2019

Austenitic stainless steels are used extensively in hydrogen gas containment components due to their known resilience in hydrogen environments. Depending on the conditions, degradation can occur in austenitic stainless steels but typically the materials retain sufficient mechanical properties within such extreme environments. In many hydrogen containment applications, it is necessary or advantageous to join components through welding as it ensures minimal gas leakage, unlike mechanical fittings that can become leak paths that develop over time. Over the years many studies have focused on the mechanical behavior of austenitic stainless steels in hydrogen environments and determined their properties to be sufficient for most applications. However, significantly less data have been generated on austenitic stainless steel welds, which can exhibit more degradation than the base material. In this paper, we assess the trends observed in austenitic stainless steel welds tested in hydrogen. Experiments of welds including tensile and fracture toughness testing are assessed and comparisons to behavior of base metals are discussed.
Fatigue of NPP Components Simulated by Non-Uniformly Strained Stainless Steel Specimens
Authors: Solin Jussi , Alhainen Jouni , Arilahti Esko , Seppänen Tommi , Mayinger Wolfgang
Published: November 2019

Comprehensive experimental research on fatigue performance of niobium stabilized (type 347) steel has revealed beneficial effects of hot holds aimed to simulate normal operation of NPP between the fatigue relevant transients. Reduction of plastic strain, extension of life and increase of endurance limit has been demonstrated in strain controlled HCF tests. Our latest results indicate moderate, but still measurable ‘hold effects’ even without any stop of straining and loading, when blocks of low rate cycles are applied between normal frequency straining at constant 325°C.

A new lab testing approach was developed to simulate the ‘component behavior’ in moderate strain concentrations within the NPP primary circuit. Strain concentrations in range of 1.5 ≤ Kε ≤ 2 are simulated through displacement controlled straining of standard and modified geometry LCF specimens. New results confirm the earlier results and introduce another consequence of holds. Cyclic softening promotes localization of strain, but hold hardening reverses this trend. The holds retard strain localization not only within the material microstructure, but also in geometric strain concentrations. We conclude that the geometric delocalization of strain can amplify beneficial hold effects for components. The local strains may reduce below the endurance limit resulting to run-out tests beyond millions of cycles, even though notable values of fatigue usage (CUF) had been accumulated during earlier phases of the tests.

Applicability of the transferability factor introduced in 2013 to the German KTA standard No. 3201.2 is supported. Exact quantification of the factor is not easy, but in all considered cases Fhold ≤ 1. This means that the fatigue usages are overestimated without this factor.
Master Curve Procedure Accounting for the Combined, Constraint, Ductile Tearing and Loading Rate Effects
Authors: Lindqvist Sebastian , Wallin Kim
Published: November 2019

The probability of brittle fracture is affected, aside from the crack driving force, by changes in constraint, loading rate and crack propagation due to an increase in the sampling volume. In addition, crack propagation, per se, can lead to constraint changes and it also affects the effective strain rate at the crack tip. Especially in the case of leak before break (LBB) where a surface crack transforms instantaneously to a through-wall crack, the increase in local strain rate combined with constraint change and ductile crack extension can be sufficient to cause a transition from ductile fracture to brittle fracture. This, and other similar events, require the development of an advanced Master Curve procedure to account for combined effect of constraint, ductile tearing and loading rate on the brittle fracture probability. A simplified methodology for achieving this is outlined and demonstrated here.
Important Effects in Environmentally Assisted Fatigue (EAF) of Austenitic and Ferritic Steel Components Including Welds and Their Consideration in a Fatigue Assessment Concept
Authors: Rudolph Jürgen , Herbst Matthias , Roth Armin , Swacek Christian , Schopf Tim
Published: November 2019

The fatigue assessment of pressure boundary components is of importance for the aging management regarding safety and reliability in nuclear power plants with light water reactors. For the evaluation of cyclic loading conditions, different country specific design codes and standards are applied to consider various mechanical and thermal loadings as well as geometrical and material effects. Those different influencing factors have also to be taken into account in the fatigue design curves. Current state of the art methods account for life time influencing factors such as temperature, surface finish, stress multi-axiality and loading history by the application of reduction factors for fatigue lives (penalty respectively margin factors) determined from fatigue design curves which are derived from laboratory test data. Other effects, such as environmental effects or hold times, are often considered with high levels of conservatism or are not taken into account at all. On the one hand, this may lead to non-conservative predictions of the materials fatigue behavior, while on the other hand, there are often large discrepancies between calculated fatigue life and practical experience from power plant operation, where the operating experience reveals much higher fatigue lifetimes as their predictions based on laboratory tests and conservative consideration of major influencing factors (plastification by Ke-factors, Environmentally Assisted Fatigue (EAF) by FEN-factors) in the calculation approach.

Therefore, Framatome GmbH, Erlangen, and the Material Testing Institute MPA Stuttgart currently conducting a cooperative research program which aims to improve the understanding of environmental and loading effects as well as of welds on fatigue life time and to improve fatigue lifetime assessment methods in the framework of the well established engineering approach. Based on the results of a previous research project of the same project partners, an experimental program is performed to investigate the effect of loading parameters and hold times on environmentally assisted fatigue (EAF). Experiments on specimens of ferritic and austenitic stainless steels and austenitic stainless steel welds as well as component tests are performed under laboratory and operating conditions to improve fatigue assessment and serve to bridge the gap between specimen behavior and component fatigue in operation.

Emanating from previous and ongoing cooperative research projects, the experimental results will contribute to the proposal of an engineering fatigue assessment concept, allowing more specific differentiation in the influencing factors for component fatigue life prediction. Furthermore, hold time effects are simulated based on further developed material models.
Determination of Inspection Intervals Based on Realistic Load Monitoring and Fracture Mechanics
Authors: Rudolph Jürgen , Bergholz Steffen , Jerinic Dalibor , Rieck Detlef
Published: November 2019

Power plant component condition monitoring with respect of fatigue and creep-fatigue requires information about the real operational loading of the component. Load monitoring systems are available on the market for that purpose. The retrieved load information can be further processed in terms of fatigue assessment based on realistic loading. Moreover, the combination of load monitoring, derivation of stress-time-histories for sentinel locations, cycle counting and fracture mechanics based assessment paves the way of substantiated determination and optimization of non-destructive testing (NDT) inspection intervals. This approach enables a continuous structural health monitoring of critical components even in the sense of online-monitoring capabilities.

This approach provides — in addition to the established fatigue analysis — concrete decisions for the remaining component lifetime and the maximum inspection intervals. This method can also be used if the previous lifetime consumption is unknown. It basically constitutes an advanced damage tolerance approach.

The paper describes a newly developed solution which combines the established Fast Fatigue Evaluation (FFE) approach of Framatome with the THERRI capabilities of TÜV NORD.
An Introduction to China National Standard for On-Board High-Pressure Hydrogen Storage Cylinders
Authors: Huang Gai , Zheng Jinyang , Hua Zhengli , Liao Binbin
Published: November 2019

High-pressure hydrogen storage is a widely used storage method for hydrogen fuel cell vehicles (HFCVs), and most of the new HFCVs use the fully-wrapped carbon fiber reinforced cylinders as the energy storage component. In order to promote the implementation of HFCVs through the creation of performance-based testing requirements for cylinders in China, the national standard named “Fully-wrapped Carbon Fiber Reinforced Cylinders with an Aluminum Liner for the On-board Storage of Compressed Hydrogen as a Fuel for Land Vehicles” (GB/T 35544) has been published in 2018. The GB/T 35544 contains requirements for the material, design, manufacture, marking, and testing of serially produced, refillable cylinders. In this work, the key points of the standard are introduced, including the category of cylinders, the maximum number of fueling cycles, material properties, design qualification tests, etc. In addition, issues that need to be further studied for developing high-pressure hydrogen storage cylinders are also indicated.
Computational Fluid Dynamics Modeling of an Experimental Thermal-Stratification Flow Case Using ABAQUS/CFD
Authors: Franken Daniel , Mohanty Subhasish
Published: November 2019

As the fleet of Pressurized Water Reactors (PWRs) in the United States begin to reach the end of their original lifespan many of them are undergoing assessment to extend their use. In order to investigate the potential for extending the life of the plant, a system level analysis of components needs to be performed in order to ensure that age and degradation of the system will not lead to a potential safety hazard. An area in which this system level investigation is particularly important is in the surge line of the pressurizer. One possible concern is that over the life of the reactor, the surge line pipe will experience thermal stratification many times. Thermal stratification can lead to significant stresses induced on the piping and over time may result in a less than ideal safety standard. Commercially available code Abaqus CFD was used to model the thermal stratification in a pipe. The corresponding experimental results, available in literature were compared. We found there is a good correlation between the experimental and computational results. However, the results discussed in this paper are based on our preliminary effort to study the capability of ABAQUS code for CFD simulation. A detailed parametric study is one of our future work.
Additive Manufactured Pressure Vessel Development: An Update
Authors: Tam Walter , Wlodarczyk Kamil , Hudak Joseph
Published: November 2019

Researchers at Northrop Grumman Innovation Systems (NGIS) have been pursuing the application of additive manufacturing (AM) technology in pressure vessel manufacture for several years. We gained significant insight after the design, analysis, fabrication, and qualification of a 1.8 liter propellant tank with additive manufactured shell in 2017. A Space Propulsion 2018 summary paper titled Additive Manufactured Pressure Vessel Shell included a description of the research and its development progress as of May 2018. Importantly, the authors discussed several items for further examination, including developing a material data base, developing fracture inspection techniques, developing fracture data to facilitate fracture analyses, assessing consistency in material properties, and examining material shedding.

In this summary paper, we review the continuing AM research and development (R&D) activities within NGIS and provide a progress update. The summary paper has three sections. Section 1 contains program background and a description of the evolving NGIS R&D program. In Section 2, we present a progress update. In Section 3, we conclude with a review of our vision towards the implementation of AM technology in space borne pressure vessel manufacture.
Establishment of Industry Standard Flange Sealing Effectiveness Measure (Leakage Rate Based) Methodology
Authors: Lutkiewicz Przemyslaw , Robertson David , Pulvino Michael
Published: November 2019

There are currently no industry accepted methods for calculating sealing effectiveness of flange connections at the research and development phase of a project. As there are many different designs of bolted piping connectors being widely used in the oil and gas industry, operators and regulators could benefit greatly from a more accurate comparison and estimate of expected flange tightness level, based on design calculations only. This paper will propose a new methodology for sealing effectiveness estimation of bolted connections based on leak rate calculations. The methodology will combine practical simplicity and advance theory to get a simple but effective engineering/designing tool to assess the seal tightness. A new proposed method will be based on the contact stress pattern (FEA results), material properties (code specification) and surface finish/roughness (manufacture requirements) as inputs and leak rate estimation as an output. The Representative Surface Element concept will be introduced and presented. In this paper, the general methodology principles will be presented and followed by an engineering example.
Impact of Carbon Macrosegregation on the Mechanical Properties of Low-Alloy Steel Forgings
Authors: Coppard Rémi , Coulon Pascal , Koyama Yoichi , Endo Masaki
Published: November 2019

Macrosegregation in large steel ingots is a known phenomenon: it corresponds to an uneven distribution of alloying elements in the bulk of the as-solidified ingot, over macroscopic scales, caused by the difference in solubility of these elements in the liquid and solid phases. As the ingot solidifies, these elements (mainly carbon, sulfur and phosphorus) concentrate in the liquid phase and are carried to the top of the ingot by convective currents. This process produces large regions of heterogeneity that can negatively impact the mechanical properties of the resulting steel.

Westinghouse is in charge of the manufacture of twelve steam generators (SG) for Electricité de France (EDF), for which the main forged parts are made of 20MND5 low alloy steel. Due to the context and concerns in France, and more broadly in the nuclear industry, on carbon macrosegregation in large scale forgings, Westinghouse led studies with the forgemaster The Japan Steel Works (JSW) in order to assess the influence of carbon content on mechanical properties of such forgings.

The present paper aims at introducing the investigation work carried out by Westinghouse, in partnership with JSW, in order to analyze the effect of increasing carbon on the 20MND5 low-alloy steel tensile and impact toughness properties.

This work was performed through:

- A thorough review of the existing literature;

- The manufacture of forged plates mock-ups, metallurgically representative of the SG channel head, containing various carbon contents (namely 0.18wt.%, 0.21wt.%, 0.26wt.% and 0.29wt.%);

- The testing of above plates to assess the evolution of tensile (tensile strength Rm, 0.2% yield strength Rp0.2 and percentage elongation after fracture) and impact properties (absorbed energy and transition temperature).
New Magnetostrictive Transducers and Applications for SHM of Pipes and Vessels
Authors: Vinogradov Sergey , Fisher Jay L.
Published: November 2019

The use of guided waves for long-range inspection of components is a rapidly growing area of the nondestructive evaluation service industry. Magnetostrictive sensors utilizing ferromagnetic strip material for the transduction effect have proven to be very effective for guided wave testing (GWT) on a variety of components. There is still a demand for enhanced sensor characterization and sensors with specific characteristics. The most challenging area is structural health monitoring (SHM) of components operating at elevated temperatures of at least 200°C.

A new configuration of a sensor for generating and receiving transverse-motion guided waves swaps the biasing and time-varying magnetic field directions. This alternative design is a reversed Wiedemann effect magnetostrictive transducer. These transducers exhibit a number of unique features compared with the more conventional Wiedemann sensor, including: (1) the use of smaller rare earth permanent magnets to achieve large, uniform, and self-sustained bias fields; (2) the use of more efficient electric coil arrangements to induce a stronger time-varying magnetic field for a given coil impedance; (3) the ability to generate both transverse and longitudinal waves; (4) they can be used on pipes ranging from a few millimeters to several meters in diameter.

In this paper, the new transducer design will be described and its performance will be analyzed in application to SHM of pressurized pipe operating at 200°C and automated omnidirectional scan of large storage tank walls.
Bayesian Approach to Estimating Fireball Parameters From Remote Sensing Data
Authors: Armstrong Derek E.
Published: November 2019

Remote sensors in the infrared region can be used to study the progression of fireballs generated from experiments involving high explosives (HE). Developing an improved understanding of HE fireballs can be used to validate and improve computational physics codes that simulate such events. In this paper, Bayesian approaches are studied to estimate time-dependent optimal fireball parameters and their uncertainties using Fourier transform infrared (FTIR) spectroscopy. The optical signal measured by an FTIR sensor provides information on the fireball due to thermal emission, particulate emission/absorption, and HE gas product emission/absorption from the fireball. FTIR sensors have the advantage of being able to capture and measure the radiance in a large part of the infrared spectrum. The parameters to be estimated from the fireball include temperature and size, soot quantity, gas species concentrations (e.g., H2O, CO2, CO), and information on the presence of metals. In general, this inverse optimization problem is difficult due to the estimated quantities being correlated, the low spectral resolution of the FTIR sensor, and the intervening atmosphere absorbing the radiation emitted from the fireball. Bayesian calibration and Bayesian model averaging are applied to address these difficulties and to quantify the uncertainty in the estimated optimal parameter values. The fireball parameter settings are evaluated by the fit of a simplified spectral model to FTIR data. The overall problem will be presented together with a description of the Bayesian approaches. In this paper, the Bayesian approaches are applied to artificially generated FTIR data to illustrate the approach.
Exploring the Uncertainty in the Equation of State for a High Explosive Fit to Heterogeneous Data
Authors: Andrews Stephen A. , Fraser Andrew M. , Jackson Scott I. , Anderson Eric K.
Published: November 2019

The extreme pressures and temperatures of the gas produced by detonating a High Explosive (HE) make it difficult to use experimental measurements to estimate the Equation Of State (EOS), the physics model that relates pressure, temperature, and density of the gas. Instead of measuring pressure directly one measures effects like the acceleration of metals driven by the HE. Typically one fits a few free parameters in a fixed functional form to measurements from a single experiment. The present work uses the optimization tool F_UNCLE to incorporate data from multiple experiments into a single EOS model for the gas produced by detonating the explosive PBX 9501. The model is verified by comparison to an experiment from outside the set of calibration data. The uncertainty in the EOS is also is examined to determine how each calibration experiment constrains the model and how the uncertainty arising from all calibration experiments affects predictions. This work identifies an EOS for HE detonation products and uncertainty about the EOS.
A Numerical Study of Laminar and Intermittently Turbulent Flow Over a Flat Plate Using Pseudo-Compressibility Model
Authors: Srivastava S. , Eastridge J. R. , Taravella B. M. , Akyuzlu K. M.
Published: November 2019

A study was conducted to investigate the characteristics of incompressible unsteady boundary layer flows (laminar and intermittently turbulent), numerically and experimentally. The main objective of the study is to validate and verify (V&V) the accuracy of the proposed pseudo-compressibility model in solving the incompressible Navier-Stokes (NS) equations. This approach will enable one to use a second order accurate (temporally and spatially) implicit finite-difference (FD) technique to solve NS equations (including RANS equations).

Here, the proposed pseudo-compressibility model is used for laminar and intermittent turbulent flow simulations. Flow over a flat plate is chosen as the benchmark case for the validation of the proposed pseudo-compressibility model. An in-house code is developed to solve the boundary layer equations using an Alternating-Direction Explicit (ADE) FD technique. The boundary layer equations are discretized using explicit FD techniques which are second order accurate. The velocity field predicted by this code is compared to the one given by Blasius’ analytical solution. A second in-house code is also developed which adopts the proposed model of pseudo-compressibility to solve the incompressible NS equations. The two dimensional, unsteady conservation of mass and momentum equations are discretized using explicit finite-difference techniques. A standard K-ε closure model is used along with RANS equation to simulate turbulent flows. The primitive variables (velocity and pressure) predicted by this code are compared to the ones predicted by a commercial CFD package (Fluent). Once the method of pseudo-compressibility is validated, it is then implemented into another in-house computer code which employs implicit FD technique and Coupled Modified Strongly Implicit Procedure (CMSIP) to solve for the unknowns of the problem under study.

The predictions based on the pseudo-compressibility model for laminar flow are validated using the results of the experiments in which Particle Image Velocimetry (PIV) technique was employed. The verification; that is, the numerical uncertainty estimation of the pseudo-compressible code was accomplished by using the Grid Convergence Index (GCI) method. The results of the present study indicate that the proposed pseudo-compressibility model is capable of predicting experimentally observed characteristics of the external flows successfully, and deviations between the predicted velocity magnitudes and experimentally measured velocities are within an acceptable range for laminar and intermittently turbulent flows conditions.
Two Pioneer Transcription Factors, Krüppel-Like Transcription Factor 4 and Glucocorticoid Receptor, Cooperatively Transactivate the Bovine Herpesvirus 1 ICP0 Early Promoter and Stimulate Productive Infection
Authors: El-mayet Fouad S. , Sawant Laximan , Thunuguntla Prasanth , Zhao Jing , Jones Clinton
Published: November 2019

Bovine herpesvirus 1 (BoHV-1), an important bovine pathogen, establishes lifelong latency in sensory neurons. Reactivation from latency is consistently induced by the synthetic corticosteroid dexamethasone. We predict that increased corticosteroid levels activate the glucocorticoid receptor (GR). Consequently, viral gene expression is stimulated by the activated GR. The immediate early transcription unit 1 promoter (IEtu1) drives expression of two viral transcriptional regulatory proteins, bovine infected cell protein 0 (bICP0) and bICP4. Interestingly, a separate early promoter also drives bICP0 expression. Two pioneer transcription factors, GR and Krüppel-like transcription factor 4 (KLF4), cooperatively transactivate the bICP0 early (E) promoter. GR and KLF15 cooperate to stimulate bICP0 E promoter activity but significantly less than GR and KLF4. The bICP0 E promoter contains enhancer-like domains necessary for GR- and KLF4-mediated transactivation that are distinct from those for GR and KLF15. Stress-induced pioneer transcription factors are proposed to activate key viral promoters, including the bICP0 E promoter, during early stages of reactivation from latency.
Cutibacterium acnes (Propionibacterium acnes) 16S rRNA Genotyping of Microbial Samples from Possessions Contributes to Owner Identification
Authors: Yang Jiayue , Tsukimi Tomoya , Yoshikawa Mia , Suzuki Kenta , Takeda Tomoki , Tomita Masaru , Fukuda Shinji
Published: November 2019

Cutibacterium acnes
is the most common and abundant bacterial species on human skin, and the gene that encodes its 16S rRNA has multiple single-nucleotide polymorphisms. In this study, we developed a method to efficiently determine the
C. acnes
16S rRNA genotype composition from microbial samples taken from the hands of participants and from their possessions. Using the
C. acnes
16S rRNA genotype composition, we could predict the owner of a possession with around 90% accuracy when the 16S rRNA gene-based microbiome profile was included. We also showed that the
C. acnes
16S rRNA genotype composition was more stable over time than the skin microbiome profile and thus is more suitable for owner identification.
A new lattice hydrodynamic model for bidirectional pedestrian flow with consideration of pedestrians’ honk effect
Authors: Zhai Cong , Wu Weitiao
Published: November 2019

Understanding the pedestrian behavior contributes to traffic simulation and facility design/redesign. In practice, the interactions between individual pedestrians can lead to virtual honk effect, such as urging surrounding pedestrians to walk faster in a crowded environment. To better reflect the reality, this paper proposes a new lattice hydrodynamic model for bidirectional pedestrian flow with consideration of pedestrians’ honk effect. To this end, the concept of critical density is introduced to define the occurrence of pedestrians’ honk event. In the linear stability analysis, the stability condition of the new bidirectional pedestrian flow model is given based on the perturbation method, and the neutral stability curve is also obtained. Based on this, it is found that the honk effect has a significant impact on the stability of pedestrian flow. In the nonlinear stability analysis, the modified Korteweg–de Vries (mKdV) equation of the model is obtained based on the reductive perturbation method. By solving the mKdV equation, the kink-antikink soliton wave is obtained to describe the propagation mechanism and rules of pedestrian congestion near the neutral stability curve. The simulation example shows that the pedestrians’ honk effect can mitigate the pedestrians crowding efficiently and improve the stability of the bidirectional pedestrian flow.
Design of effective bulk potentials for nematic liquid crystals via colloidal homogenisation
Authors: Canevari Giacomo , Zarnescu Arghir
Published: November 2019

We consider a Landau–de Gennes model for a suspension of small colloidal inclusions in a nematic host. We impose suitable anchoring conditions at the boundary of the inclusions, and we work in the dilute regime — i.e. the size of the inclusions is much smaller than the typical separation distance between them, so that the total volume occupied by the inclusions is small. By studying the homogenised limit, and proving rigorous convergence results for local minimisers, we compute the effective free energy for the doped material. In particular, we show that not only the phase transition temperature, but also any coefficient of the quartic Landau–de Gennes bulk potential can be tuned, by suitably choosing the surface anchoring energy density.
EgoVis: A Visual Analysis System for Social Networks Based on Egocentric Research
Authors: Lu Qiang , Huang Jing , Ge Yifan , Wen Dajiu , Chen Bin , Yu Ye
Published: November 2019

The development of crowd intelligence makes the structure of social network more complex and changeable. Research on social network should be more in-depth and focus on the changes of structure. Ego-network, which represents the relationship between specific individual and the related people, is a hot issue among the research of dynamic social network. The evolution of ego-network is highly dynamic and pluralistic, it is hard to capture its evolutionary pattern over time. To help users analyze the individual characteristics and hidden patterns in multivariate ego-network, we present EgoVis, an interactive visual analysis system for exploring and analyzing complex structural relationships in dynamic network. Based on the task requirements of network evolution analysis, we propose a task taxonomy which is suitable for ego-network research and analysis, design novel visual fonts, and analyze the evolution of dynamic ego-network relations from the three dimensions: overview, subgroup, and detail-ego. Finally, the validity and practicability of EgoVis are verified on DBLP citation network dataset.
Hochschild cohomology of m-cluster tilted algebras of type 𝔸̃
Authors: Gubitosi Viviana
Published: November 2019

In this paper, we compute the dimension of the Hochschild cohomology groups of any [Formula: see text]-cluster tilted algebra of type [Formula: see text]. Moreover, we give conditions on the bounded quiver of an [Formula: see text]-cluster tilted algebra [Formula: see text] of type [Formula: see text] such that the Gerstenhaber algebra [Formula: see text] has nontrivial multiplicative structures. We also show that the derived class of gentle [Formula: see text]-cluster tilted algebras is not always completely determined by the dimension of the Hochschild cohomology.
From molecular energy landscapes to equilibrium dynamics via landscape analysis and markov state models
Authors: Kabir Kazi Lutful , Akhter Nasrin , Shehu Amarda
Published: November 2019

Molecular dynamics (MD) simulation software allows probing the equilibrium structural dynamics of a molecule of interest, revealing how a molecule navigates its structure space one structure at a time. To obtain a broader view of dynamics, typically one needs to launch many such simulations, obtaining many trajectories. A summarization of the equilibrium dynamics requires integrating the information in the various trajectories, and Markov State Models (MSM) are increasingly being used for this task. At its core, the task involves organizing the structures accessed in simulation into structural states, and then constructing a transition probability matrix revealing the transitions between states. While now considered a mature technology and widely used to summarize equilibrium dynamics, the underlying computational process in the construction of an MSM ignores energetics even though the transition of a molecule between two nearby structures in an MD trajectory is governed by the corresponding energies. In this paper, we connect theory with simulation and analysis of equilibrium dynamics. A molecule navigates the energy landscape underlying the structure space. The structural states that are identified via off-the-shelf clustering algorithms need to be connected to thermodynamically-stable and semi-stable (macro)states among which transitions can then be quantified. Leveraging recent developments in the analysis of energy landscapes that identify basins in the landscape, we evaluate the hypothesis that basins, directly tied to stable and semi-stable states, lead to better models of dynamics. Our analysis indicates that basins lead to MSMs of better quality and thus can be useful to further advance this widely-used technology for summarization of molecular equilibrium dynamics.
A Preliminary Study on the Design Method for Large‐Diameter Deep‐Hole Presplit Blasting and Its Vibration‐Isolation Effect
Authors: Xiao Shuangshuang , Wang Hongsheng , Dong Guowei
Published: November 2019

Presplit blasting can reduce vibration and back impact induced by cast blasting, thus resulting in a smooth bench slope. To design reasonable presplit blasting parameters, this research investigated the formation of presplit faces based on the explosion mechanics and revealed the cracking mechanism of presplit blasting. According to the stress distribution in the vicinity of the blast holes under the action of explosive stress waves and blasting gas, we deduced theoretical formulae for parameters including charge mass in blast holes, hole spacing, and distance from presplit blast holes to cushion holes. On this basis, a method was proposed for the design of large‐diameter deep‐hole presplit blasting. Field testing was conducted by setting different spacing for presplit blast holes, to monitor the blasting‐induced vibration. The results showed that appropriate hole spacing can reduce the particle vibration velocity and the attenuation index of blasting‐induced vibration changed slightly while the attenuation coefficient decreased significantly; the formed presplit faces were smooth and had a high half‐cast factor. Finally, the reasonable hole spacing for presplit blasting, distance from presplit blast hole to the cushion hole, and the charge mass in blast holes in the Heidaigou open‐pit coal mine were determined, respectively.
The Role of Cardiolipin and Mitochondrial Damage in Kidney Transplant
Authors: Miranda-Díaz Alejandra Guillermina , Cardona-Muñoz Ernesto Germán , Pacheco-Moisés Fermín Paul
Published: November 2019

Chronic kidney disease (CKD) is highly incident and prevalent in the world. The death of patients with CKD is primarily due to cardiovascular disease. Renal transplantation (RT) emerges as the best management alternative for patients with CKD. However, the incidence of acute renal graft dysfunction is 11.8% of the related living donor and 17.4% of the cadaveric donor. Anticardiolipin antibodies (ACAs) or antiphospholipid antibodies (APAs) are important risk factors for acute renal graft dysfunction. The determination of ACA or APA to candidates for RT could serve as prognostic markers of early graft failure and would indicate which patients could benefit from anticoagulant therapy. Cardiolipin is a fundamental molecule that plays an important role in the adequate conformation of the mitochondrial cristae and the correct assembly of the mitochondrial respiratory supercomplexes and other proteins essential for proper mitochondrial function. Cardiolipin undergoes a nonrandom oxidation process by having pronounced specificity unrelated to the polyunsaturation pattern of its acyl groups. Accumulation of hydroxyl derivatives and cardiolipin hydroperoxides has been observed in the affected tissues, and recent studies showed that oxidation of cardiolipin is carried out by a cardiolipin-specific peroxidase activity of cardiolipin-bound cytochrome c. Cardiolipin could be responsible for the proapoptotic production of death signals. Cardiolipin modulates the production of energy and participates in inflammation, mitophagy, and cellular apoptosis. The determination of cardiolipin or its antibodies is an attractive therapeutic, diagnostic target in RT and kidney diseases.
ОСОБЛИВОСТІ ЗДОРОВ’Я НАСЕЛЕННЯ СТАРШИХ ВІКОВИХ ГРУП
Authors: Dyachuk M. D. , Gruzieva T. S. , Inshakova G. V.
Published: November 2019

Мета: встановити сучасні особливості та тенденції здоров’я населення старших вікових груп для виявлення потреб та оптимізації надання медичної допомоги.

Матеріали і методи. При виконанні дослідження використано бібліографічний, медико-статистичний та інформаційно-аналітичний методи. Науковою базою дослідження був багатопрофільний заклад охорони здоров’я. Проаналізовано дані про захворюваність, поширеність хвороб, інвалідність, смертність населення віком 60 років і старше впродовж 2014–2018 рр.

Результати. Виявлено тенденції до збільшення поширеності хвороб серед населення літнього віку на 15,8 % та первинної захворюваності – на 18,2 %. Встановлено головні причини звернень до закладу охорони здоров’я та їх динаміку впродовж чотирирічного періоду. Збільшення звернень населення зумовлено зростанням частоти вперше виявлених захворювань нервової системи (на 204,5 %), кістково-м’язової системи (на 180,2 %), органів дихання  (на 78,8 %) та сечостатевої системи (на 36,7 %), що потребує посилення профілактичних заходів та підвищення якості лікування. Комплексно оцінено позитивні та негативні зміни в стані здоров’я пацієнтів літнього віку, включаючи показники інвалідизації та смертності, на основі яких окреслено пріоритетні завдання з удосконалення медичного обслуговування пацієнтів старших вікових груп.

Висновки. Визначені особливості та тенденції стану здоров’я населення старших вікових груп, яких обслуговують в багатопрофільному закладі охорони здоров’я, є підґрунтям для з’ясування проблемних ситуацій, існуючих викликів, встановлення першочергових потреб та їх прогнозування на перспективу, пріоритизації завдань щодо удосконалення медичного обслуговування населення літнього віку.
A Numerical Analysis of 2D Unsteady Magnetohydrodynamics Nanofluid Flow Through an Exponentially Accelerated Vertical Plate with Variable Viscosity by Using Explicit Finite Difference Method
Authors: Biswas R.
Published: November 2019

This paper discusses the numerical investigation of viscous incompressible nanofluid on unsteady magnetohydrodynamics (MHD) chemically radioactive flow through an exponentially accelerated porous plate with variable viscosity. A system of governing nonlinear partial differential equations
(PDEs) is transformed into ordinary differential equations (ODEs) by the as usual mathematical technique of transformation. Then, the obtained non-dimensional nonlinear partial differential equations (PDEs) are solved by using explicit finite difference technique (EFDM). Besides, the numerical
results are calculated by FORTRAN programming language. In order to accuracy of numerical investigation a convergence stability test (NCT) has been carried out where we have obtained the convergence criteria of Prindtl number Pr ≥ 0.47; thermophoresis parameter Nt
≥ 0.80 and Lewis number Le ≥ 0.28 when initial boundary conditions U = T = C = 0 and for Δτ = 0.0005, ΔX = 0.50 and ΔY = 0.50. After those convergence criteria, the numerical solutions for velocity, temperature and concentration
profiles are obtained for various dimensionless parameters. Those solutions are graphically discussed by using the tecplot-9 software. Moreover, the skin friction coefficient, Nusselt number, Sherwood number, Isotherms and Streamline are also investigated by tabular form.