bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards design sociology
Authors: Lupton Deborah
Published: October 2017

In this review essay, I introduce and map the field of what I call “design sociology”. I argue that design research methods have relevance to a wide range of sociological research interests, and particularly for applied research that seeks to understand people's engagements with objects, systems and services, better engage publics and other stakeholders, work towards social change, and identify and intervene in futures. I discuss 3 main ways in which design sociology can be conducted: the sociology of design, sociology through design and sociology with design. I explain key terms in design and dominant approaches in social design research—participatory, critical, adversarial, speculative, and ludic design. Examples of how sociologists have already engaged with design research methods are outlined. The essay concludes with suggestions about what the future directions of design sociology might be.
Risk factors and clinical outcomes of pediatric liver transplant recipients with post‐transplant lymphoproliferative disease in a multi‐ethnic Asian cohort
Authors: Huang James Guoxian , Tan Mervin Ye Qing , Quak Seng‐Hock , Aw Marion Margaret
Published: October 2017

Background

We aimed to evaluate clinical characteristics, risk factors, and disease outcomes for liver transplant recipients (LTR) with post‐transplant lymphoproliferative disease (PTLD) at our center.

Methods

Retrospective review of data of all pediatric LTR (1991‐2015) was conducted.

Results

The overall incidence of PTLD was 16.4% (18/110), the majority (13/18) were early lesions, while 3/18 were polymorphic/monomorphic PTLD. The risk factors significant on univariate analysis were as follows: mean age (years) at transplant (1.66 vs 4.76, P = .006); age <2 years at transplant (odds ratio [OR] 3.53 [95% confidence interval [CI]: 1.16‐10.73], P = .026); cytomegalovirus (CMV) primary infection (OR 11.39 [95% CI: 3.44‐37.7], P < .001); recipient CMV seronegativity (OR 7.50 [95% CI: 2.02‐27.78], P = .003); presence of CMV end‐organ disease (OR 4.00 [95% CI: 1.22‐13.16], P = .022); Chinese ethnicity; and higher mean duration of intravenous ganciclovir prophylaxis. In multivariate analysis, CMV primary infection (OR 5.22 [95% CI: 1.25‐21.87], P = .024), CMV seronegativity (OR 5.91 [95% CI: 1.13‐30.90, P = .035]), and having acute cellular rejections (ACR) prior to PTLD (OR 5.53 [95% CI: 1.43‐21.48, P = .013]) were significant risk factors for PTLD, with the latter two factors having a synergistic effect in increasing PTLD risk in a stratified analysis. The final multivariate model in predicting the risk of PTLD, utilizing CMV primary infection, recipient CMV seronegativity, and ACR before PTLD as predictive variables, was statistically significant (likelihood ratio chi square statistic = 25.18, P < .0001 with df = 3).

Conclusions

We report a unique clinicopathologic and risk factor profile in our cohort—early lesion PTLD accounts for the majority and the incidence of monomorphic PTLD remains low. In addition, we show a synergism between CMV naivety and ACR on PTLD risk, a higher prevalence of gastrointestinal manifestations, and a lack of significant association with Epstein‐Barr virus seronegativity.
A RhABF2/Ferritin module affects rose (Rosa hybrida) petal dehydration tolerance and senescence by modulating iron levels
Authors: Liu Jitao , Fan Youwei , Zou Jing , Fang Yiqun , Wang Linghao , Wang Meng , Jiang Xinqiang , Liu Yiqing , Gao Junping , Zhang Changqing
Published: October 2017

Plants often develop the capacity to tolerate moderate and reversible environmental stresses, such as drought, and to re‐establish normal development once the stress has been removed. An example of this phenomenon is provided by cut rose (Rosa hybrida) flowers, which experience typical reversible dehydration stresses during post‐harvest handling after harvesting at the bud stages. The molecular mechanisms involved in rose flower dehydration tolerance are not known, however. Here, we characterized a dehydration‐ and abscisic acid (ABA)‐induced ferritin gene (RhFer1). Dehydration‐induced free ferrous iron (Fe2+) is preferentially sequestered by RhFer1 and not transported outside of the petal cells, to restrict oxidative stresses during dehydration. Free Fe2+ accumulation resulted in more serious oxidative stresses and the induction of genes encoding antioxidant enzyme in RhFer1‐silenced petals, and poorer dehydration tolerance was observed compared with tobacco rattle virus (TRV) controls. We also determined that RhABF2, an AREB/ABF transcription factor involved in the ABA signaling pathway, can activate RhFer1 expression by directly binding to its promoter. The silencing of RhABF2 decreased dehydration tolerance and disrupted Fe homeostasis in rose petals during dehydration, as did the silencing of RhFer1. Although both RhFer1 and Fe transporter genes are induced during flower natural senescence in plants, the silencing of RhABF2 or RhFer1 accelerates the petal senescence processes. These results suggest that the regulatory module RhABF2/RhFer1 contributes to the maintenance of Fe levels and enhances dehydration tolerance through the action of RhFer1 locally sequestering free Fe2+ under dehydration conditions, and plays synergistic roles with transporter genes during flower senescence.
Nitric oxide is required for the insulin sensitizing effects of contraction in mouse skeletal muscle
Authors: Zhang Xinmei , Hiam Danielle , Hong Yet‐Hoi , Zulli Anthony , Hayes Alan , Rattigan Stephen , McConell Glenn K.
Published: October 2017

Key points

People with insulin resistance or type 2 diabetes can substantially increase their skeletal muscle glucose uptake during exercise and insulin sensitivity after exercise.

Skeletal muscle nitric oxide (NO) is important for glucose uptake during exercise, although how prior exercise increases insulin sensitivity is unclear.

In the present study, we examined whether NO is necessary for normal increases in skeletal muscle insulin sensitivity after contraction ex vivo in mouse muscle.

The present study uncovers, for the first time, a novel role for NO in the insulin sensitizing effects of ex vivo contraction, which is independent of blood flow.

The factors regulating the increase in skeletal muscle insulin sensitivity after exercise are unclear. We examined whether nitric oxide (NO) is required for the increase in insulin sensitivity after ex vivo contractions. Isolated C57BL/6J mouse EDL muscles were contracted for 10 min or remained at rest (basal) with or without the NO synthase (NOS) inhibition (NG‐monomethyl‐l‐arginine; l‐NMMA; 100 μm). Then, 3.5 h post contraction/basal, muscles were exposed to saline or insulin (120 μU ml−1) with or without l‐NMMA during the last 30 min. l‐NMMA had no effect on basal skeletal muscle glucose uptake. The increase in muscle glucose uptake with insulin (57%) was significantly (P < 0.05) greater after prior contraction (140% increase). NOS inhibition during the contractions had no effect on this insulin‐sensitizing effect of contraction, whereas NOS inhibition during insulin prevented the increase in skeletal muscle insulin sensitivity post‐contraction. Soluble guanylate cyclase inhibition, protein kinase G (PKG) inhibition or cyclic nucleotide phosphodiesterase inhibition each had no effect on the insulin‐sensitizing effect of prior contraction. In conclusion, NO is required for increases in insulin sensitivity several hours after contraction of mouse skeletal muscle via a cGMP/PKG independent pathway.
Leak Rates of Gasses Through Packing Seals With Different Analytical Approaches
Authors: Aweimer Ali Salah Omar , Bouzid Abdel-Hakim , Kazeminia Mehdi
Published: October 2017

Predicting leakage in packed stuffing boxes is a major engineering challenge to designers and end users. Due to the different working conditions and material products, the determination of the flow regime present in packing rings is not a straightforward task to predict. This paper presents a study on the ability of micro channel flow models to predict leak rates through packing rings made of soft materials such as graphite. A methodology based on the experimental characterization of the porosity parameters is developed to predict leak rates at different compression stress levels. Three different models are compared to predicate the leakage, where the diffusive and second order flow models are derived from Naiver-Stokes equations and incorporate the boundary conditions of an intermediate flow regime to cover the wide range of leak rate levels. The lattice model is based on porous media of packing rings as packing bed (Dp). The flow porosity parameters (Rc,Dp) of the micro channels assumed to simulate the leak paths present in the packing are obtained experimentally. The predicted leak rates from different gasses (He, N2, Ar) are compared to those measured experimentally, in which the set of packing rings is mainly subjected to different gland stresses and pressures.
Gaseous Deflagration in Piping: Part 1 — Experimental Observations
Authors: Ligon Thomas C. , Gross David J. , Minichiello John C.
Published: October 2017

The focus of this paper is on gaseous deflagration in piping systems and the corresponding implications on piping analysis and design. Unlike stable detonations that propagate at a constant speed and whose pressure-time histories can in some cases be predicted analytically, deflagration flame speeds and pressure-time histories are transient and depend on both the gas mixture and geometry of the pipe. This paper presents pressure and pipe strain data from gaseous deflagration experiments in long and short test apparatuses fabricated from either 2-inch or 4-inch diameter pipes. These data are used to demonstrate a spectrum of measured pressure-time histories and corresponding pipe response. It is concluded that deflagrations can be categorized as either “high” or “slow” speed with respect to pipe response. Slow deflagrations can be treated as quasi-static pressurizations, but high speed deflagrations can generate shock waves that dynamically excite the pipe.

The existence of a transition from quasi-static to dynamic response has ramifications in regards to piping structural analysis and design, and a method for predicting the expected deflagration structural response using a semi-empirical flame acceleration model is proposed.
Effect of Uncontrolled Hydrogen Injection on SCC Susceptibility of 304L Steel in High Temperature Water
Authors: Medina-Almazán A. L. , Galicia-Aguilar G. , Zenteno-Suárez J. C. , Arganis-Juárez C. , López-García N. , Marín-Almazo M.
Published: October 2017

For operation of existing nuclear power plants (NPPs) beyond their design lifetime (up to 80 years), one of the main issues is the assessment of the performance of its structures, systems and components (SSC) during the period of extended operation. In Boiling water reactors (BWR), the reactor pressure vessel internals (RPVI) components are submitted to both, Neutron irradiation and high oxidizing environment which lead (together, by itself or mixed with a sensitized condition) to stress corrosion cracking (SCC) [1–4]. One of the measures to mitigate SCC in BWR is the decrease of the Electrochemical Corrosion Potential (ECP) of the structural materials by the injection of hydrogen (1-2 ppm H2) and Noble Metal Chemical Addition (NMCA) or On-Line NobleChemTM (OLNC). However, ECP is a thermodynamic measurement that little says about the kinetics of the process of SCC; by the other side, literature shows that hydrogen has an effect on austenitic stainless steels under Light Water Reactors (LWR) environments in corrosion fatigue crack initiation and corrosion fatigue crack growth [4], whilst it has been observed an hydrogen effect by Slow Strain Rate Tests (SSRT) only in stainless steels irradiated to high fluence and in Pressurized Water Reactor (PWR) primary water [4].

The results of Slow Strain Rate Tests (SSRT) performed in a 304L SS at 288°C and 8 MPa are presented in this work. 50% cold worked 304L SS was tested in High Oxygen Water Chemistry (HOWC, no hydrogen injection) and in HWC with Platinum hydrothermal deposits (PtHD); by the other hand, sensitized 304L SS with PtHD was tested under excess hydrogen injection condition (EHI, >8 ppm H2). It was observed that both, 50% cold worked 304L SS tested under HOWC and sensitized 304L SS with Pt deposits tested under excess hydrogen injection, fail in a brittle way, by transgranular stress corrosion cracking (TGSCC), whereas 50% cold worked 304L SS with Pt deposits tested in HWC presents a ductile fracture surface. Even the brittle behavior of the fracture surface of sensitized 304L SS with Pt deposits tested under uncontrolled hydrogen injection, it is not a embrittlement effect on the final elongation (εf), nevertheless it is seen a hardness increase that could be attributed to H2.
Life Extension of the 9975 Package As a Storage Container: Thermal Analysis
Authors: Kiflu Bereket , Hensel Steve J.
Published: October 2017

The 9975 shipping package is used to store plutonium bearing material with a heat release of up to 19 Watts at the Department of Energy (DOE) Savannah River Site (SRS). Individual 9975 packages have been used to store these materials for nearly 15 years. The 9975 package contains non-metallic components such as the elastomeric dual O-ring seals, used to ensure containment at the vessel closures, and a fiberboard over pack which provides impact and fire resistance to the containment vessels. These non-metallic components degrade during long term storage, particularly when higher heat generating contents are packaged. Degraded fiberboard properties result in higher peak internal 9975 package material temperatures during a fire accident event.

The thermal performance of the 9975 shipping package was evaluated for a sequential accident consisting of a fire and drop which locally ruptures the outer drum. The package is exposed to an off-normal 58.3°C (137°F) ambient temperature prior to being fully engulfed in a fire for 1.5 hours at 815.6°C (1500°F). Subsequently the fiberboard smolders for 1.0 hour at 760°C (1400°F) at the location of drum rupture, followed by cool down to the ambient temperature. The thermal evaluation considered both the beginning-of-life (as-designed) condition and after 20 years of service as a plutonium material storage container. The results of the evaluation demonstrate that the 9975 shipping package maintains containment during initial and after 20 years of service. The maximum Primary Containment Vessel dual O-ring temperatures during the facility fire-drop-smoldering accident are 163.9°C (327°F) and 186.1°C (367°F) for beginning of life and after 20 years of service, respectively, which are within the allowable accident temperature limit of 204.4°C (400°F). Thus, the 9975 shipping package meets its intended function to provide containment.
Evaluation of Mechanical Behavior of Taper Pipe Threads in the Tightening Process by Finite Element Analysis and Elementary Theory of Solid Mechanics
Authors: Fukuoka Toshimichi , Hirai Yuki
Published: October 2017

There are two types of pipe threads, i.e., parallel and tapered ones. The former is used for mechanically connecting hollow cylinder-shaped structures, and the latter is usually employed for connecting thin pipes and tubes. The primary function required for taper pipe threads is to prevent the leakage of contained fluids. In order to ensure the sealing performance, target taper pipe threads need to be tightened with proper conditions. However, it seems that a standard tightening guideline with sufficient mechanical background has not been established. In this paper, using helical thread models, the relationship between assembly torque and rotation angle of threaded pipe is studied by FEA. The relationship between rotation angle and radial contact force between male and female threads, which is regarded as an index of the sealing performance, is also evaluated in like manner. In the numerical calculations, finite element analyses are performed as elastic and elastic-plastic problems, in which nominal dimeter of threads, pipe wall thickness and coefficient of friction on the thread contact surface are changed systematically, aiming at the establishment of a practical tightening guideline. Additionally, a simple method is proposed to evaluate the contact force between male and female threads, using elementary theory of solid mechanics. It is shown that the simple method can predict the contact force with sufficient accuracy, comparing to the calculation results by FEA.
Interim Safe Storage of Radioactive Materials at the Savannah River Site
Authors: Kyriazidis Lucas L. , Hensel Steve J. , Jordan Jeff M.
Published: October 2017

Storage of plutonium bearing materials at the US Department of Energy Savannah River Site (SRS) typically are packaged in DOE-STD-3013 welded containers which are stored in 9975 shipping packages. However, some materials are packaged in non-welded metal containers which consist of a can-bag-can configuration. These non-welded containers and the 9975 package provide safe containment of the plutonium bearing materials. Additionally, the materials must be stabilized such that adverse reactions do not occur during storage. Lastly, a surveillance program of these containers provides field and laboratory data with respect to package aging and potential degradation. The packaging, material stabilization, and surveillance requirements are identified in an Interim Safe Storage Criteria (ISSC) Program at SRS. This paper provides a high level overview of the ISSC program. Interim storage is defined as the storage prior to long term plutonium disposition.
Introduction to Actual Field Repair for Skirt Attachment Portion in Coke Drum
Authors: Murakami Takushi , Shishido Yasuhiko , Yoshimoto Makoto
Published: October 2017

Cracks on skirt attachment welds in coke drum fabricated in 1979 installed in a coker plant in Japan were completely repaired by the team of authors in 2016. Coke drums undergo cyclic operations typically in the temperature range from ambient temperature to about 500°C (930°F). Consequently, repetitive large thermal stress which leads to cracks is developed in skirt attachment portion of coke drum. Usually, the existence of serious cracks that need to be repaired extensively is recognized by the regular inspections such as plant turnarounds, whereas the overall schedule of turnarounds from shutdown to start-up is planned carefully in advance with consideration in terms of production loss as well. Accordingly, time constraint becomes a critical problem to consider when an appropriate countermeasure is expected. Although the authors have faced this kind of problem due to serious cracks detected at turnaround, weld repair for entire circumferential seam of skirt attachment and post weld heat treatment for the repaired area have completed satisfactorily. This paper summarizes the actual repair and inspection methods including the work flow from the planning stage in order to accomplish the repair work within the limited turnaround period and achieve the expected quality for further use.
The Correlation Analysis of the Big Data for Pipeline Defect
Authors: Zhang Hewei , Dong Shaohua , Zhang Laibin
Published: October 2017

With the increasing of pipe diameter and operation pressure, the severity of the accident consequences has been increased, especially for the impact on the high consequence area. The safety of oil and gas pipeline is very important.

At the same time, a lot of data were produced during the process and the amount of detection data signal has also reached the TB level. However, because the relationship between these data sets has not been established, most part of the “Big Data” in which the safety information of pipeline hidden was ignored and discarded.

In order to effectively use the relevant pipeline data of the defects, the mutual information method was adopted to establish a correlation analysis model. Its main purpose was extracting all the factors that lead to pipeline defects from the “Big Data” and determined the crucial factors from them.

A pipe segment on a long-distance pipeline with the length of 100km was taken as a case. Based on the correlation analysis model, the crucial factors which had great correlation relationship with pipeline defect were extracted, so as to provide reference to accident prevention. It is a new way of pipeline safety management.
Design Modification to Mitigate the Reactor Inner Zone Inlet Header Temperature in a CANDU Reactor
Authors: Li Bing , Tang Preston , Khan Khurram , Bhatia Akash
Published: October 2017

The Reactor Inner Zone Inlet Header (RIZIH) temperatures have raised more rapidly in the CANDU units in general, compared to the original aging predictions. The RIZIH high temperature alarms are required to be monitored to prevent operation outside the safe operating envelope as supported by the safety analysis. To prevent RIZIH temperature alarms, increasing RIZIH temperatures are being mitigated through changes in unit operating conditions which have caused power derates (as low as 87% Full Power) and a loss of revenue. In order to address the above concerns, a CANDU utility has initiated a study to evaluate multiple design alternatives and develop the best design option to improve RIZIH temperatures control. Seven design alternatives were assessed to a sufficient level based on their risk, suitability, economics, and effectiveness in managing RIZIH temperature with minimum system level impacts to interfacing systems. The study concluded that the external feedwater bypass of High Pressure Heater is the preferred option.
Load Classification for Dynamic Responses on Single Mass Cantilever Structure With Bi-Linear Material Property
Authors: Kai Satoru , Otani Akihito
Published: October 2017

Nuclear Power Plants (NPPs) are designed to withstand postulated earthquake events. Seismic loads induced by a seismic event on essential structures such as a piping are typically evaluated with two different load categories: inertia loads and deformation loads which are also called as load-controlled loads and displacement-controlled loads, respectively. The inertia force is still believed to govern failure mode of piping components as almost of all design codes for NPPs give weight at qualifying the inertia loads as primary stress components for piping. The first paper PVP2015-45287 [22] anticipated a structure excited by a lower frequency than the natural frequency which is considered as an excitation at Rigid condition could result in plastic collapse because of a minimal recovering force counteracting the deformation. However, the second paper PVP2016-63363 [23] which applied an elastic-plastic analysis showed the different conclusion that a single mass cantilever structure at Rigid condition finally behaved as Soft condition which was anticipated as a stable condition in the paper along the progress of the plastic deformation on the structure. This result implies that the current design codes which assume elastic-behavior may include significant over-conservatism to ensure the adequacy of structures under seismic condition. As many experimental results are showing, very large seismic loads which excessively exceed the design limit barely caused failure in piping components. This paper investigates the relationship between inertia forces and element forces on a single mass cantilever model applying a bi-linear material property against several random time-history loads which are adjusted to represent the said excitation conditions. This paper also clarifies the correlation between deformations due to the excitations and the inertia/element forces observed on the models. This study takes over the previous researches published as PVP2015-45287 and PVP2016-63363.
A Design Based Approach to Material Selection for Advanced High Temperature Reactor Components
Authors: Sham T.-L. , Jetter Robert I.
Published: October 2017

Material selection decisions for advanced reactor concepts are frequently based on simple consideration of required wall thickness for a particular component and the resultant cost based on averaged cost per unit, usually by weight. However, this approach does not take into consideration the overall impact of other material properties on design feasibility. An example would be the interrelated roles of thermal conductivity, thermal expansion and creep-strength on the design of components to withstand cyclic and sustained loading. The problem is that this would nominally require a detailed design and loading definition. However, as presented herein, a meaningful comparison can be achieved by selective evaluation of the ratios of the material properties required to achieve a particular performance goal for a particular design objective; for example, the relative ability to accommodate axial thermal gradients in a pressurized cylindrical vessel. This paper covers the development of such critical parametric ratios for a number of component elements and loadings and illustrates their application.
Deficient Materials in Hot Reheat Seam Welded High-Energy Piping
Authors: Coleman Kent , Rosinski Stan , Foulds Jude
Published: October 2017

Although failures of seam welded high-energy piping date to about 1970, the utility industry concern about premature failure of longitudinal seam welded piping has been of the utmost importance since the mid 1980’s driven primarily by well publicized piping failures at that time. The major concern is with hot reheat piping, some of which failed catastrophically resulting in substantial costs and personnel injury.

Many utilities manage their high energy piping integrity through a combination of engineering analysis and periodic inspections. At many utilities around the world, however, high energy piping has not received the attention that normally occurs after a major failure because the perception is that there have been few failures. EPRI has compiled a database of over 50 failures and large areas of damage in utility piping systems around the world and it does not include the entire utility experience but still demonstrates the need for a diligent high energy piping integrity management program.

The investigation of a recent failure in a 42 in. (1066 mm) diameter, 2 in. (50.8 mm) thick wall, ASTM A155 (American Society of Testing and Materials) seam welded hot reheat pipe demonstrated a first of its kind damage mechanism which determined that inappropriate welding filler metal was utilized for at least some of the weld passes resulting in a weldment that was weak in creep. Due to the placement of the incorrect welding filler metal, the failure occurred as a leak instead of a rupture however, the damage on the inside surface of the pipe extended for over 9ft. (2743 mm). This paper presents the results of the failure analysis and life assessment work performed and provides guidance for the rest of the utility fleet.
Application of One-Dimensional Hydrogen Event Pressure Pulse Propagation and Diminishment Model to Analysis and Design of Hanford WTP Piping
Authors: Pellman Abby M. , Collin Jean E. , Minichiello John C.
Published: October 2017

The Hanford Tank Waste Treatment and Immobilization Plant (WTP) will process waste slurries capable of generating a dispersed non-condensable gas phase. Under postulated conditions, the generated bubbles may coalesce to form flammable gas pockets. Ignition of such a gas pocket may result in a deflagration or detonation that can transmit a pressure pulse into the surrounding gas-liquid slurry. The transmitted pressure pulses will impose structural loads on the piping and associated supports. These loads, and their evolution as the pressure pulse propagates throughout the system, must be considered in the design of WTP piping. Recent work has demonstrated good agreement between experimental data and predictions of the pressure diminishment associated with the propagation of a pressure pulse through a bubbly medium using a simplified onedimensional pursuit model (i.e., model of rarefaction wave overtaking shock front).

This paper describes the application of the pursuit model to flammable gas pocket scenarios postulated in the design of WTP piping. The model is adapted to consider the effect of the time-evolution of the ignited gas pocket and parametric simulations are used to demonstrate the effect of key variables on the propagation and diminishment of the pressure pulse in piping. The practical applicability of the pursuit model for WTP piping design / analysis is illustrated through the development of a correlation that appropriately represents the results of the pursuit model for a wide range of conditions and that could be readily incorporated into existing structural analysis tools. Arguments are presented supporting the applicability of the simplified model even for scenarios in which the ignited gas pocket does not satisfy the model’s onedimensional assumption.
Study on the Stream-Wise Fluidelastic Instability of Rotated Square Arrays of Circular Cylinders Subjected on Cross-Flow
Authors: Nakamura Tomomichi , Tsujita Tomoki
Published: October 2017

Stream-wise fluidelastic instability has recently been in the spotlight due to a practical event in steam generators at a nuclear power plant [1]. The instability has been reported to occur easily in rotated triangular arrays, but at all hardly in normal triangular arrays [2][3]. In square arrays, no instability has been reported in the authors’ test facility [4].

This paper presents the test results on rotated square arrays of the pitch-diameter ratios from 1.2 to 1.5. The tests have been conducted with a wind tunnel, where cylinders have been constrained to move in only one specific direction, either stream-wise or transverse to the flow. The results indicate that fluidelastic vibrations occur only in the stream-wise direction. The critical factor corresponds to the previous data reported in some guidelines [5], but here the factor is related mainly to stream-wise instability.
Analysis and Optimization of the Deep-Hole Drilling Technique in Measuring Complex Residual Stress
Authors: Zheng Gang , Hossain Sayeed , Shen Feng , Truman Chris
Published: October 2017

The aim of the present study was to utilize a complex residual stress generated within a welded circular disc to further investigate the standard deep-hole drilling (DHD) technique and the newly developed over-coring deep-hole drilling (oDHD) technique in accurately measuring residual stresses well over yield stress. Finite Element Analysis (FEA) was used to optimize and extend the deep-hole drilling technique and improve its accuracy. The standard DHD procedure involves 4 steps. (1) A reference hole is gun-drilled through the component. (2) The internal diameter of the reference hole is measured at different angular positions through the depth of the component. (3) A cylindrical section with the reference hole as its longitudinal axis is trepanned free from the component. (4) Finally, the relaxed internal diameter is re-measured at the same angular positions and the same depths. The drilling, trepanning procedures and the parameters of the deep-hole drilling technique were all studied in detail to optimize the technique. Comparison is made between the FEA predicted residual stress in the weld, the measurements and the reconstructed residual stresses of the measurements. The close correlations confirmed the suitability of new modifications made in the deep-hole drilling technique to account for plasticity when measuring near yield residual stresses present in a component.
Performance Evaluation of a Respirator Vortex Cooling Device
Authors: Elizondo Ashley D. , Iacovone Robert K.
Published: October 2017

The United States Department of Energy’s Savannah River Site (SRS) in Aiken, South Carolina, is dedicated to promoting site-level risk-based inspection practices in order to maintain a safe and productive work environment. Protective suits are worn by personnel working in contaminated environments. These suits require that cooling be applied to keep the interior temperature within safe and comfortable limits. A vortex tube, also known as the Ranque-Hilsch vortex tube, can provide the necessary cooling. As mechanical devices void of moving components, vortex tubes separate a compressed gas into hot and cold streams; the air emerging from the “hot” end reaching a temperature of 320 degrees F, and the air emerging from the “cold” end reaching a temperature of negative 25 degrees F [1]. Routing the cold stream of the vortex tube to the user’s protective suit facilitates the required cooling.

Vortex tubes currently in use at SRS are pre-set, through sole modification by and within the SRS Respiratory Equipment Facility (REF), to provide a temperature reduction between 40 and 45 deg F. When a new model of vortex tube capable of user adjustment during operation recently became available, prototype testing was conducted for product comparison. Similar cooling performance between the old and new models is achievable. Implementing the use of the new model of vortex tube at SRS will result in significant cost savings because the product could be shipped directly to the end user, circumventing adjustment by the REF. Production units were acquired to be subjected to complete product analysis at SRS utilizing a statistical test plan. The statistical test plan, data, thermodynamic calculations, and conclusions were reviewed.
Residual Stress Assessment for Pressure Vessel Subject to Thermal Shock
Authors: Hsiao Jushin , Qian Haiyang , Brunner Christopher , Bober Thomas R. , D’Amico Lynn , Loomis Robert W.
Published: October 2017

API 579-1/ASME FFS-1 Part 9 provides assessment procedures for evaluating crack-like flaws in components to determine if it is fit for continued service. Although residual stress distribution is required as an input to perform a fatigue life assessment, no procedure or guideline is available for evaluating this crack driving force resulting from thermal shocks.

Through a systematic analysis, a conservative residual stress distribution can be obtained for pressure vessels subject to thermal shocks. For the two thick-walled vessels considered, the maximum residual stress occurs when the vessel is half filled with water. The conservative residual stress provides the needed input when using API 579-1/ASME FFS-1 for evaluating crack-like flaws in components. Dependence of the residual stress on film coefficient, temperature difference between water and metal surface, and water level inside the vessel is also presented so that refinement can be made on life assessment when additional field data becomes available.
Expanding Plug Wedge Test for Evaluating Hoop Tensile Properties of Fuel Cladding
Authors: Jiang Hao , Wang Jy-An John
Published: October 2017

An expanding plug wedge test method was developed to determine hoop tensile properties of irradiated fuel cladding in a hot cell [1]. Ring specimens with the plug-wedge insert were fabricated based Finite Element Analysis (FEA) design. After several design and modification iterations, the protocol was validated for M5 and Zr-4 cladding. Results show that tested ring specimens have uniform radial expansion deformation in the gage section. The test data processing procedure was developed based on the energy approach to generate hoop stress-strain correlation. α factor estimated from FEA was used to remove dissipated friction energy. With the proposed method, optimized specimen design, and data processing procedure, the protocol validates that the measured piston load, plug extension, and ring radial expansion can be effectively and accurately converted into the hoop stress-strain curve for clad tubing structural material characterization. Validation proved that the expanding plug wedge test method is robust and can be easily performed.
Expansion of Multi-Purpose Steam Facility and Application to Acoustic Resonance in a Closed Side Branch Investigating Effects of Static Pressure Under Wet Steam Flow
Authors: Uchiyama Yuta , Morita Ryo
Published: October 2017

Flow-induced acoustic resonances in piping with closed side branches or T-junctions are one of the phenomena causing severe structural vibration and fatigue damage of the piping and components in many engineering applications such as power plants. Practical piping systems of power plants often have a steam flow, and moreover, the steam state can be not only dry steam but also wet steam. From our previous experiments under low-pressure dry and wet steam flows using a single side branch, higher acoustical damping was confirmed under wet steam than that under dry steam, which is considered to be caused by the existing liquid phase. Although the static pressure in practical steam piping is often higher than that in our previous experiments, the effects of the static pressure on acoustical damping under a wet steam flow have not been clarified. Thus, we constructed a new test facility that can be used to perform continuous flow test under dry and wet steam flows with higher pressures than our previous test facility. In this paper, we give an overview of the new steam test facility and some experimental results for the acoustic resonance in a single side branch under higher-pressure dry and wet steam flows than those in our previous studies, using the new facility to investigate and evaluate the effects of the static pressure.
Using Isochronous Method to Calculate Creep Damage in Pressure Vessel Components: Part 2
Authors: Nadarajah Chithranjan , Hantz Benjamin F. , Krishnamurthy Sujay
Published: October 2017

This paper is Part 2 of two papers illustrating how isochronous stress strain curves can be used to calculate creep stresses and damage for pressure vessel components. Part 1 [1], illustrated the use of isochronous stress strain curves to obtain creep stresses and damages on two simple example problems which were solved using closed form solution. In Part 2, the isochronous method is implemented in finite element analysis to determine creep stresses and damages on pressure vessel components. Various different pressure vessel components are studied using this method and the results obtained using this method is compared time explicit Omega creep model. The results obtained from the isochronous method is found to be in good agreement with the time explicit Omega creep model.
Extending Drum Life While Increasing Throughput in a Delayed Coking Unit
Authors: Kirkpatrick Kenneth , Antalffy Les , Millet Barry , Miller George
Published: October 2017

As throughput is increased and cycle times are reduced for delayed cokers, many owners are experiencing an increased occurrence of repairs and drum failures. Typically, other equipment in the facilities are upgraded while the coker unit is left unchanged and is expected to perform under more severe cyclic conditions. The operators are required to keep increasing the throughput and decrease the cycle time to meet targeted production. Most Coke drum failures are due to the high cyclic thermal stresses. Cyclic thermal stresses along with their increased occurrence lead to premature failures and cracking. It can be shown that by adding a 3rd drum to a 2 drum unit, the drum life can be extended by several fold, possibly eliminate the need to replace the coke drums and at the same time increase throughput.
Experimental Demonstration of Failure Modes on Bellows Structures Subject to Internal Pressure
Authors: Ando Masanori , Yada Hiroki , Tsukimori Kazuyuki , Ichimiya Masakazu , Anoda Yoshinari
Published: October 2017

In this study, in order to develop the evaluation method of the pressure toughness of bellows structures under the beyond design base event, the pressure failure tests and finite element analysis (FEA) of the bellows structures subjected to internal pressure were performed. Since the several tests and FEA results were reported previously by current authors, the additional tests were performed by the specimen simulating the real setting situation in the actual plant and for demonstrating the plain failure modes. Test specimens consist of the single and double ply bellows made of SUS304 were used. Total five specimens were tested, and one specimen was attached the guard pipe around the bellows to simulate the actual situation in the plant to confirm the effect of the neighbor structures to the ultimate toughness. The maximum pressure obtained in all tests were over 10 times larger than the estimated results of limiting design pressure based on in-plain instability by the EJMA standards; although the test specimens were pressurized exceed the pressure of buckling deformation. Because it is very difficult problem to simulate the inversion of the convolution accompanied convolutions contact for FEA with implicit method, FEA with simplified technique and explicit analysis were performed to simulating the complex deformation of the test specimen, and then these results were estimated in some procedures to compare with the test results. Three failure modes identified in the tests, however, the complex deformation behavior make it difficult to simulate by ordinary FEA procedure and to estimate the ultimate toughness of the bellows structures under the internal pressure. Therefore several kinds of idea for evaluating the ultimate toughness of the bellows structures were execute and suggested.
Dynamic Load Factor for Surge Load on Pipe Using the Stress Wave Propagation Methodology
Authors: Seena Abu
Published: October 2017

The full time history method for calculating the pipe stresses and restraint loads due to transient flow event requires high computing memory and long simulation time. Alternately, the static equivalent method has been extensively used in power and process industry where a dynamic load factor is used to account for the dynamic amplification response of suddenly applied surge/hammering loads on pipe. In practice, the DLF is multiplied on the maximum value of dynamic force depending on the time rise of load. Due to the complexity of calculating DLF, the engineers adopt maximum value of DLF = 2.0 irrespective of the load variation. The present paper discusses the uncertainty and inaccuracy involved in performing approximate analysis or static equivalent analysis and shows the significance and need of performing full force time history analysis. A new methodology has been derived for the estimation of approximate DLF from the full force time history profiles. Using the stress wave propagation methodology, the DLF can be estimated for the pipe with axial restraints and guides. The axial line stoppers are precondition to apply present method, which can be easily included during design phase of the pipe routes. The DLF’s are computed for sample force curve with various other parameters and are compared with the FEA results. It has also been shown that the load amplification does not scale with the displacement amplification. With proposed methodology the DLF for can be calculated for each pipe. Then it is recommended to perform the static analysis with the estimated DLF’s based on full time history profiles.
Computation of Fluid Thrust Force From the Pressure Release Tank of Nuclear Power Plant Pressurizer
Authors: Xiong Fu-Rui , Jiang Nai-Bin
Published: October 2017

Pressure release tank is a key component of nuclear power plant safeguard. Evaluating the fluid thrust force against nearby structures from high pressure and high temperature flow jet under postulated accidents is an essential task for nuclear system design and safety estimation. In this work, flow jet impingement from pressure release tank to nearby building roof is computed via a two-stage strategy. First, the 1-dimensional RELAP5 code is applied to estimate thermal-hydraulic conditions at pressure release tank outlet. The thermal-hydraulic computational model includes key components of pressure release tank and its connection to the pressurizer. Based upon the thermal-hydraulic estimation at the pressure release tank outlet, detailed computational fluid dynamics (CFD) simulation is performed with full considerations of how flow thrust is applied on nearby structures. The two-stage computational strategy provides a practical paradigm of fluid thrust force estimation for industrial applications.
Assessment of a Stress-Free Temperature Model for Residual Stresses in Surface Cladding of a Reactor Pressure Vessel
Authors: Bass B. Richard , Williams Paul T. , Dickson Terry L. , Klasky Hilda B.
Published: October 2017

This paper describes further results from an ongoing study of a simplified engineering model that is intended to account for effects of clad residual stresses on the propensity for initiation of preexisting inner-surface flaws in a commercial nuclear reactor pressure vessel (RPV). The deposition of stainless steel cladding during fabrication of an RPV generates residual stresses in the cladding and the heat affected zone of the under-lying base metal. In addition to residual stress, thermal strains are generated by the differential thermal expansion (DTE) of the cladding and base material due to temperature changes during normal operation. A simplified model used in the ORNL-developed FAVOR probabilistic fracture mechanics (PFM) code accounts for the clad residual stress by incorporating a stress-free temperature (SFT) approach. At the stress-free temperature (Ts-free), the model assumes there is no thermal strain, i.e., the thermal expansion stresses and clad residual stresses offset each other. For normal cool-down transients applied to the RPV, interactions of the latter stresses generate additional crack driving forces on shallow, internal surface-breaking flaws near the clad/base metal interface; those flaws tend to dominate the RPV failure probability computed by FAVOR. In a previous report from this study (PVP2015-45086), finite element analysis was used to compare the stresses and stress-intensity factors (SIF) during a cool-down transient for two cases: (1) the existing SFT model of FAVOR, and (2) directly applied RPV clad residual stress (CRS) distribution obtained from empirical (hole-drilling) measurements made at room temperature on an RPV that was never put into service. However, those analyses were limited in scope and focused on a single flaw orientation.

In this updated study, effects of CRS on the SIF histories computed for both circumferential and axial flaw orientations subjected to a cool-down transient were determined from an extended set of finite element analyses. Specifically, comparisons were made between results from applying CRS experimental data to ABAQUS two-dimensional, inner-surface flaw models and those generated by the FAVOR SFT model. It is demonstrated that the FAVOR-recommended SFT value of 488 °F produces conservatively high values of SIF relative to the use of CRS profiles in the ABAQUS models. For the vessel and flaw geometry and transient under study, the circumferential flaw (360° continuous) required a decrease of SFT down to 390 °F to match the CRS SIF histories. For the infinite axial flaw model, a decrease down to 300 °F matched the CRS SIF histories. Future plans are described to develop more general conclusions regarding the FAVOR model.
Fatigue Life and Reliability Consideration During Field Repair of Coke Drum and Piping
Authors: Chadda Tej , Anand Umakanthan
Published: October 2017

Aging coke drums and their connected overhead piping in delayed coking units experience fatigue cracks which most commonly occur at the skirt junction and high stress pipe welds.

This paper presents 2-case studies of this new cost-effective repair methodology with fatigue resistant design upgrade. The first case study applies to coke drum weld build-up solid skirt crack repair and the second for overhead vapor line weld crack repair.

This paper presents new field repair methodology which could also improve long term fatigue resistance. It also suggests optimizing the thermal operation & thermal gradients of coke drums for further reliability improvement.

Based on FEA, successful field execution and our experience, these case studies demonstrate a long term improvement in reliability and fatigue life of the order of 2.5 to 3 or higher especially if combined with thermal operation optimization.