bluuebunny/crossref_metadata_2025 huggingface dataset:
Simple Tool to Evaluate Airtightness in Chilean Homes
Authors: González Cáceres Alex , Recart Carolina , Espinoza Rodrigo , Bobadilla Ariel
Published: October 2016

Given the high impact that air leaks have on buildings’ energy expenses, most developed countries have set out norms which regulate their presence in homes. Chile will soon begin this process; however, the airtightness revision strategy in envelopes has not been resolved as of yet. This article presents a tool to Assess Airtightness in Design, EHeD. The software will allow predicting the performance of homes under the regulations which will be set out, aiding designers, builders or owners to make decisions when making changes to improve airtightness. EHeD has been validated through pressurization tests in diverse homes across the country, with results that are in line with expectations, thus validating its calculation model. The methodology considers three stages: determining the main factors that have an impact on the airtightness in Chilean homes, preparing an airtightness database for each component (wall, windows and doors) and preparing a calculation model that is integrated in an IT interface.
The Effect of Environmental, Social and Governance Consistency on Economic Results
Authors: Ferrero-Ferrero Idoya , Fernández-Izquierdo María , Muñoz-Torres María
Published: October 2016

This study aims to explore how environmental, social and governance (ESG) consistency impacts the firm performance, specifically, the relationship between ESG performance and economic performance (EP). This study posits that the company’s commitment and effectiveness towards the creation of consistent competitive advantage in environmental, social and governance dimensions constitutes an intangible value that leads improvements in corporate performance. This work uses a panel dataset for listed firms of the EU-15 countries during the period 2002 to 2011 and applies Generalized method of moments (GMM) estimator system in order to address the potential unobserved heterogeneity and dynamic endogeneity. The main results reveal that the global effect of ESG performance on EP for those firms that present interdimensional consistency is greater than the rest, except for higher levels of ESG performance.
Emergent Imaginaries and Fragmented Policy Frameworks in the Canadian Bio-Economy
Authors: Birch Kean
Published: October 2016

Climate change means that countries like Canada need to find suitable transition pathways to overcome fossil-fuel dependence; one such pathway is the so-called ‘bio-economy’. The bio-economy is a term used to define an economic system in which biological resources (e.g., plants) form the basis of production and production processes. For example, it would involve the replacement of petroleum energy, inputs, chemicals, and products with bioenergy, biological inputs, bio-chemicals, and bio-products. A number of countries and jurisdictions have established policy strategies in order to promote and support the development of a bio-economy, exemplified by the European Union where the bio-economy represents a key pillar in its broader Horizon 2020 strategy. Other countries, like Canada, do not yet have an over-arching bio-economy strategy, but have a series of diverse, and often competing, policy visions and frameworks. It is useful to analyse countries like Canada in order to understand how these policy visions and policy frameworks are co-constituted, and what this might mean for the development of an over-arching bio-economy strategy. This raises a number of questions: How is the bio-economy imagined by different social actors? How are these imaginaries and policy frameworks co-produced?
Effect of Phase Change Materials (PCMs) Integrated into a Concrete Block on Heat Gain Prevention in a Hot Climate
Authors: Hasan Ahmad , Al-Sallal Khaled , Alnoman Hamza , Rashid Yasir , Abdelbaqi Shaimaa
Published: October 2016

In the current study, a phase change material (PCM) contained in an insulated concrete block is tested in extremely hot weather in the United Arab Emirates (UAE) to evaluate its cooling performance. An insulated chamber is constructed behind the block containing PCM to mimic a scaled down indoor space. The effect of placement of the PCM layer on heat gain indoors is studied at two locations: adjacent to the outer as well as the inner concrete layer. The inclusion of PCM reduced heat gain through concrete blocks compared to blocks without PCM, yielding a drop in cooling load indoors. The placement of PCM and insulation layers adjacent to indoors exhibited better cooling performance compared to that adjacent to the outdoors. In the best case, a temperature drop of 8.5% and a time lag of 2.6 h are achieved in peak indoor temperature, rendering a reduction of 44% in the heat gain. In the tested hot climate, the higher ambient temperature and the lower wind speed hampered heat dissipation and PCM re-solidification by natural ventilation. The findings recommend employing a mechanical ventilation in hot climates to enhance regeneration of the PCM to solid state for its optimal performance.
Re-Linking Governance of Energy with Livelihoods and Irrigation in Uttarakhand, India
Authors: Buechler Stephanie , Sen Debashish , Khandekar Neha , Scott Christopher
Published: October 2016

Hydropower is often termed “green energy” and proffered as an alternative to polluting coal-generated electricity for burgeoning cities and energy-insecure rural areas. India is the third largest coal producer in the world; it is projected to be the largest coal consumer by 2050. In the Himalayan state of Uttarakhand, India, over 450 hydroelectric power schemes are proposed or are under development. Hydropower projects ranging from micro hydro (run-of-the-river systems with generating capacity up to 100 kW) to large reservoirs (storage systems up to 2000 MW) such as the Tehri Dam are in various stages of planning, construction or implementation. Run-of-the-river hydropower projects are being developed in Uttarakhand in order to avoid some of the costs to local communities created by large dams. Stakeholders in this rapid hydropower expansion include multiple actors with often diverging sets of interests. The resulting governance challenges are centered on tradeoffs between local electricity and revenue from the sale of hydropower, on the one hand, and the impacts on small-scale irrigation systems, riparian-corridor ecosystem services, and other natural resource-based livelihoods, on the other. We focus on the Bhilangana river basin, where water dependent livelihoods differentiated by gender include farming, fishing, livestock rearing and fodder collection. We examine the contradictions inherent in hydropower governance based on the interests of local residents and other stakeholders including hydropower developers, urban and other regional electricity users, and state-level policymakers. We use a social justice approach applied to hydropower projects to examine some of the negative impacts, especially by location and gender, of these projects on local communities and then identify strategies that can safeguard or enhance livelihoods of women, youth, and men in areas with hydropower projects, while also maintaining critical ecosystem services. By assessing the Bhilangana basin case, we also offer hydropower–livelihoods–irrigation nexus lessons for headwater regions across the Himalayas and globally.
Characteristics of Droughts in South Africa: A Case Study of Free State and North West Provinces
Authors: Botai Christina , Botai Joel , Dlamini Lucky , Zwane Nosipho , Phaduli Elelwani
Published: October 2016

The Free State (FS) and North West (NW) Provinces are often hard hit by droughts with impacts on water availability, farm production and livestock holdings. The South African government declared the two Provinces drought disaster areas in the 2015/2016 hydrological year. This is a major drawback, since both the Provinces play an important role to South African economy as they are a haven to agricultural production and have major water reservoirs in South Africa. This study was undertaken to investigate the historical evolution of drought within the FS and NW Provinces over the past 30 years. The Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) calculated based on monthly meteorological data from 14 weather/climate stations within the FS and NW Provinces were used to explore and characterize variation in drought intensity, duration, frequency and severity in FS and NW Provinces during 1985–2015. Results indicate that there exist localized positive and negative trends with spatial dependence across the selected stations. In particular, about 60% of the weather stations exhibiting a decreasing trend are located in FS Province, suggesting that FS has being experiencing increasing drought during the analyzed period compared to NW Province. Results from the analysis of drought evaluation indicators (DEIs) calculated from SPEI suggest that drought severity and frequency was more pronounced in FS while the intensity of the drought was more in NW Province during 1985–2015. In addition, based on SPEI calculations, moderate drought occurrences increased during 1985–1994 and 1995–2004 periods and decreased thereafter (2005–2015) in both Provinces. Drought classification based on parameters derived from SPEI produced similar results for mild drought occurrences during the same time scales.
Comparing blends and blocks: Synthesis of partially fluorinated diblock polythiophene copolymers to investigate the thermal stability of optical and morphological properties
Authors: Boufflet Pierre , Wood Sebastian , Wade Jessica , Fei Zhuping , Kim Ji-Seon , Heeney Martin
Published: October 2016

The microstructure of the active blend layer has been shown to be a critically important factor in the performance of organic solar devices. Block copolymers provide a potentially interesting avenue for controlling this active layer microstructure in solar cell blends. Here we explore the impact of backbone fluorination in block copolymers of poly(3-octyl-4-fluorothiophene)s and poly(3-octylthiophene) (F-P3OT-b-P3OT). Two block co-polymers with varying block lengths were prepared via sequential monomer addition under Kumada catalyst transfer polymerisation (KCTP) conditions. We compare the behavior of the block copolymer to that of the corresponding homopolymer blends. In both types of system, we find the fluorinated segments tend to dominate the UV–visible absorption and molecular vibrational spectral features, as well as the thermal behavior. In the block copolymer case, non-fluorinated segments appear to slightly frustrate the aggregation of the more fluorinated block. However, in situ temperature dependent Raman spectroscopy shows that the intramolecular order is more thermally stable in the block copolymer than in the corresponding blend, suggesting that such materials may be interesting for enhanced thermal stability of organic photovoltaic active layers based on similar systems.
THREE TEMPERATE NEPTUNES ORBITING NEARBY STARS*
Authors: Fulton Benjamin J. , Howard Andrew W. , Weiss Lauren M. , Sinukoff Evan , Petigura Erik A. , Isaacson Howard , Hirsch Lea , Marcy Geoffrey W. , Henry Gregory W. , Grunblatt Samuel K. , Huber Daniel , Braun Kaspar von , Boyajian Tabetha S. , Kane Stephen R. , Wittrock Justin , Horch Elliott P. , Ciardi David R. , Howell Steve B. , Wright Jason T. , Ford Eric B.
Published: October 2016

We present the discovery of three modestly irradiated, roughly Neptune-mass planets orbiting three nearby Solar-type stars. HD 42618 b has a minimum mass of 15.4 ± 2.4

, a semimajor axis of 0.55 au, an equilibrium temperature of 337 K, and is the first planet discovered to orbit the solar analogue host star, HD 42618. We also discover new planets orbiting the known exoplanet host stars HD 164922 and HD 143761 (ρ CrB). The new planet orbiting HD 164922 has a minimum mass of 12.9 ± 1.6

and orbits interior to the previously known Jovian mass planet orbiting at 2.1 au. HD 164922 c has a semimajor axis of 0.34 au and an equilibrium temperature of 418 K. HD 143761 c orbits with a semimajor axis of 0.44 au, has a minimum mass of 25 ± 2

, and is the warmest of the three new planets with an equilibrium temperature of 445 K. It orbits exterior to the previously known warm Jupiter in the system. A transit search using space-based CoRoT data and ground-based photometry from the Automated Photometric Telescopes (APTs) at Fairborn Observatory failed to detect any transits, but the precise, high-cadence APT photometry helped to disentangle planetary-reflex motion from stellar activity. These planets were discovered as part of an ongoing radial velocity survey of bright, nearby, chromospherically inactive stars using the Automated Planet Finder (APF) telescope at Lick Observatory. The high-cadence APF data combined with nearly two decades of radial velocity data from Keck Observatory and gives unprecedented sensitivity to both short-period low-mass, and long-period intermediate-mass planets.
A SURVEY OF MAGNETIC WAVES EXCITED BY NEWBORN INTERSTELLAR He+ OBSERVED BY THE ACE SPACECRAFT AT 1 au
Authors: Fisher Meghan K. , Argall Matthew R. , Joyce Colin J. , Smith Charles W. , Isenberg Philip A. , Vasquez Bernard J. , Schwadron Nathan A. , Skoug Ruth M. , Sokół Justyna M. , Bzowski Maciej , Zurbuchen Thomas H. , Gilbert Jason A.
Published: October 2016

We report observations of low-frequency waves at 1 au by the magnetic field instrument on the Advanced Composition Explorer (ACE/MAG) and show evidence that they arise due to newborn interstellar pickup He+. Twenty-five events are studied. They possess the generally predicted attributes: spacecraft-frame frequencies slightly greater than the He+ cyclotron frequency, left-hand polarization in the spacecraft frame, and transverse fluctuations with minimum variance directions that are quasi-parallel to the mean magnetic field. Their occurrence spans the first 18 years of ACE operations, with no more than 3 such observations in any given year. Thus, the events are relatively rare. As with past observations by the Ulysses and Voyager spacecraft, we argue that the waves are seen only when the background turbulence is sufficiently weak as to allow for the slow accumulation of wave energy over many hours.
A HIGH FRACTION OF Lyα EMITTERS AMONG GALAXIES WITH EXTREME EMISSION LINE RATIOS AT z ∼ 2*
Authors: Erb Dawn K. , Pettini Max , Steidel Charles C. , Strom Allison L. , Rudie Gwen C. , Trainor Ryan F. , Shapley Alice E. , Reddy Naveen A.
Published: October 2016

Star-forming galaxies form a sequence in the [O iii] λ5007/

versus [N ii] λ6584/

diagnostic diagram, with low-metallicity, highly ionized galaxies falling in the upper left corner. Drawing from a large sample of UV-selected star-forming galaxies at

with rest-frame optical nebular emission line measurements from Keck-MOSFIRE, we select the extreme ∼5% of the galaxies lying in this upper left corner, requiring log([N ii]/

) 

and log([O iii]/

) 

. These cuts identify galaxies with

, when oxygen abundances are measured via the O3N2 diagnostic. We study the

properties of the resulting sample of 14 galaxies. The mean (median) rest-frame

equivalent width is 39 (36) Å, and 11 of the 14 objects (79%) are

 emitters (LAEs) with

. We compare the equivalent width distribution of a sample of 522 UV-selected galaxies at

identified without regard to their optical line ratios; this sample has mean (median)

equivalent width −1 (−4) Å, and only 9% of these galaxies qualify as LAEs. The extreme galaxies typically have lower attenuation at

than those in the comparison sample and have ∼50% lower median oxygen abundances. Both factors are likely to facilitate the escape of

: in less dusty galaxies

photons are less likely to be absorbed during multiple scatterings, while the harder ionizing spectrum and higher ionization parameter associated with strong, low-metallicity star formation may reduce the covering fraction or column density of neutral hydrogen, further easing

escape. The use of nebular emission line ratios may prove useful in the identification of galaxies with low opacity to

photons across a range of redshifts.
ExtractingTenebrio molitor protein while preventing browning: effect of pH and NaCl on protein yield
Authors: Yi L. , Van Boekel M.A.J.S. , Lakemond C.M.M.
Published: October 2016

The potential of insects as an alternative protein source for food applications was investigated by studying the effect of pH and NaCl on extraction yield of water-soluble proteins fromTenebrio molitor, while preventing browning due to polyphenol oxidation. Minimum protein solubility (29.6%) was at pH=4-6 and maximum (68.6%) at pH=11. Protein extraction at 0.1 M NaCl, pH=10 gave a recovery of 100%. The observed increase in browning at pH=8-11 corresponded to a lower monomeric phenol content. Sodium bisulphite (studied from 0.5-4%) could prevent browning, whereas ascorbic acid (studied in the range 0.01-0.04%) could not prevent as strong as sodium bisulphite. After acid precipitation (pH=4) an isolate with a protein content of 74% (yield of 22% of total protein) was obtained. It was observed that proteins fromT. molitor behave more or less the same as proteins from meat and fish with respect to aqueous extraction, which is of relevance for food industry when usingT. molitor protein as an ingredient in food products.
Small Incision Lenticule Extraction (SMILE) as Re-treatment for a Thick LASIK Flap
Authors: Catalan-Lopez Sara , Portas-Ferradas Alba Mariña , Cadarso-Suarez Luis , Rodriguez-Rodriguez Adriana
Published: October 2016

PURPOSE:

To report the case of a residual refractive error after LASIK for moderate myopia successfully re-treated several years later using the small incision lenticule extraction (SMILE) technique.

METHODS:

Case report.

RESULTS:

Following LASIK, the patient showed a central flap thickness of 269 microns, whereas residual stromal bed thickness under the flap was 210 microns. SMILE was performed within the flap. In this less invasive surgical procedure, the residual stromal bed is not manipulated and ablation is conducted on the existing flap. At 6 months of follow-up, visual and anatomical outcomes were satisfactory. Uncorrected distance visual acuity was 20/20 and refractive error was +0.75 −0.50 × 30°.

CONCLUSIONS:

In selected patients with a thick flap and thin residual stromal bed after LASIK, SMILE as re-treatment may be a good option.

[
J Refract Surg.
2016;32(10):718–720.]
Impact of Suction Loss During Small Incision Lenticule Extraction (SMILE)
Authors: Liu Manli , Wang Jianchao , Zhong Wen , Wang Danyang , Zhou Yugui , Liu Quan
Published: October 2016

PURPOSE:

To evaluate the clinical results of suction loss in eyes during small incision lenticule extraction (SMILE).

METHODS:

This prospective paired-eye case study enrolled 8,490 eyes of 4,296 patients, of which 35 eyes experienced suction loss during the SMILE procedure while being treated for myopia or myopic astigmatism. The eyes with suction loss were re-treated with SMILE, femtosecond laser-assisted LASIK (FS-LASIK), or pseudo SMILE, and the fellow eyes were treated with SMILE. Patients were examined before surgery and at 1 day, 1 week, and 1 and 3 months postoperatively. Corrected distance visual acuity (CDVA) and uncorrected distance visual acuity (UDVA), manifest refraction, higher order aberrations (HOAs), and morphologic modifications of corneal architecture were evaluated. At 3 months, patients were asked if they preferred the vision in either eye.

RESULTS:

High-contrast CDVA was worse in the eyes that suffered loss of suction than in the fellow eyes at 1 week postoperatively (two-tailed paired
t
tests,
P
= .04), but not at 1 and 3 months. There was no statistical significance between the two treatments in the safety and efficacy indices or the 3rd and 4th order aberrations at 3 months postoperatively (two-tailed paired
t
tests, all
P
> .05). No apparent abnormalities were observed in the corneas by frequency-domain optical coherence tomography.

CONCLUSIONS:

Re-treatment with femtosecond laser for incomplete SMILE was safe, predictable, and effective, and the patients did not perceive a difference in vision.

[
J Refract Surg.
2016;32(10):686–692.]
Transepithelial Iontophoresis Versus Standard Corneal Collagen Cross-linking: 1-Year Results of a Prospective Clinical Study
Authors: Vinciguerra Paolo , Romano Vito , Rosetta Pietro , Legrottaglie Emanuela F. , Piscopo Raffaele , Fabiani Claudia , Azzolini Claudio , Vinciguerra Riccardo
Published: October 2016

PURPOSE:

To compare 1-year transepithelial corneal collagen cross-linking with iontophoresis (I-CXL) outcomes with standard CXL (S-CXL) epithelium-off for progressive keratoconus.

METHODS:

Forty eyes of 40 patients with progressive keratoconus were included in this comparative, prospective clinical study. Corrected distance visual acuity (CDVA), spherical equivalent, cylinder refraction, corneal topography, Scheimpflug tomography, aberrometry, and endothelial cell count were assessed at baseline and at 1, 3, 6, and 12 months of follow-up.

RESULTS:

Patients received either I-CXL (20 eyes) or S-CXL (20 eyes). Functional parameters (visual acuity and aberrometry) showed a significant improvement (
P
< .05) after 6 and 12 months of follow-up in both groups. In the I-CXL group, the CDVA showed a rapid recovery of vision after 3 months (
P
= .01) compared to baseline. Morphological parameters showed a significant reduction of maximum keratometry in the S-CXL group by −1.05 ± 1.51 diopters (D) after 12 months, whereas the I-CXL group curvature was stable (−0.31 ± 1.87 D). Minimum pachymetry values were stable even after 12 months of follow-up in the I-CXL group, whereas a significant corneal thinning 12 months following treatment was recorded in the S-CXL group (
P
< .001). None of the patients had continuous progression of keratoconus or had to repeat CXL procedures. Endothelial cell counts did not change significantly (
P
> .05).

CONCLUSIONS:

The 1-year outcomes suggest that I-CXL might be comparable to S-CXL in stabilizing the progression of the degenerative ectatic disease. Additionally, quicker improvement of functional parameters was reported in the I-CXL group.

[
J Refract Surg.
2016;32(10):672–678.]
Comparison Between Mix-and-Match Implantation of Bifocal Intraocular Lenses and Bilateral Implantation of Trifocal Intraocular Lenses
Authors: Bilbao-Calabuig Rafael , González-López Felix , Amparo Ferrer , Alvarez Gemma , Patel Sunni R. , Llovet-Osuna Fernando
Published: October 2016

PURPOSE:

To investigate the visual outcomes between mix-and-match bifocal intraocular lenses (IOLs) (ReSTOR +2.50 and +3.00 diopters [D]; Alcon Laboratories, Inc., Fort Worth, TX) versus bilateral implantation of a trifocal IOL (FineVision; PhysIOL, Liège, Belgium).

METHODS:

Twenty-three patients (average age: 56.3 ± 6.9 years; range: 45 to 71 years) referred for lens phacoemulsification and IOL implantation were included in this study. Patients were randomly assigned to two groups. The FineVision group was bilaterally implanted with the FineVision trifocal IOL and the ReSTOR group was implanted with mix-and-match bifocal ReSTOR +2.50 and +3.00 D IOLs. A 3-month postoperative check was performed, and manifest refraction and logMAR uncorrected (UDVA) and corrected (CDVA) distance and near visual acuities were recorded. Monocular and binocular defocus curve testing was performed under photopic (85 cd/m
2
) conditions in 0.50-D defocus steps. Contrast sensitivity was measured monocularly and binocularly under mesopic conditions at spatial frequencies of 3, 6, 12, and 18 cycles per degree using the CSV-1000 contrast test (VectorVision, Greenville, OH).

RESULTS:

There were no reported differences in monocular distance visual acuity or refractive outcomes between groups (
P
> .05). Furthermore, there were no significant differences in contrast sensitivity between the three IOLs (
P
> .05). The FineVision group achieved better monocular and binocular near and intermediate visual acuities under defocus curve testing than the ReSTOR group (
P
< .05).

CONCLUSIONS:

Binocular implantation of the FineVision trifocal IOL provided a better range of visual acuities at near and intermediate distances than mix-and-match bifocal IOL implantation.

[
J Refract Surg.
2016;32(10):659–663.]
Ratcheting Simulation of Z2CN18.10 Austenitic Stainless Steel under Pre-Strain Conditions
Authors: Wang Yong , Peng You Gang , Chen Xu
Published: October 2016

Uniaxial ratcheting behaviors of Z2CN18.10 austenitic stainless steel under both tensile pre-strain (TP) and compressive pre-strain (CP) were experimentally studied at room temperature. The experimental results show that: TP restrains ratcheting strain accumulation of subsequent cycling with positive mean stress; lower level of CP is found to accelerate ratcheting strain accumulation while higher level of CP retards the accumulation. Based on the Ohno-Wang II kinematic hardening rule, rate-independent model, viscoplastic model, isotropic hardening model and a modified model were constructed to describe the ratcheting behaviors under various pre-strain conditions. All the four models gave fairly good prediction on ratcheting strains for various TP. The isotropic hardening model and modified model predicted acceptable ratcheting strain though still showed slight tendency of over prediction.
Research on High Temperature Compression and Creep Properties of Porous Copper Alloy
Authors: Chen Li , Chen Jian , Li Wei , Li Cong , Li Xiong Fei , He Jian Jun
Published: October 2016

The powder sintering process is adopted for preparing the porous Cu-35Ni-15Al alloy.The microstructure was observed by using scanning electron microscopy. Mechanical properties were tested and compared at different temperatures and stress conditions. This thesis also studied the impact of stress on creep properties of Cu-35Ni-15Al alloy,The results show there are roughly three deformation stages of high temperature compression deformation.The microscopic deformation was mainly the curved, collapsed and folded holes.The creep resistance performance of porous Cu-35Ni-15Al alloys weakens with the increasing pressure.
Microstructural Evolution of Nuclear Power Steel A508-III in the Creep Process at 800°C
Authors: Xie Zhi Gang , He Yan Ming , Yang Jian Guo , Gao Zeng Liang
Published: October 2016

The A508-III steel is widely used to manufacture the lower heads of commercial reactor pressure vessels (RPV). In severe accident, the reactor core in the RPV begins to melt and meanwhile the technology of in-vessel retention (IVR) exerts its role. In this case the inner surface of RPV will expose to temperatures over a phase transition temperature. However, the significant nonlinear feature of creep curve of A508-III steel suffered heterogeneous damage was not studied. In this work, the creep tests were performed for the steel at the phase transition temperature of 800°C. The microstructural evolution at different creep stages was characterized by scanning electron microscopy and transmission electron microscopy. The results show that, at the second creep stage, more coarsening second phase particles occur in the steel. With the creep processing, the grain size and diameter of second phase particles increase. At the tertiary creep stage, the grain size increases significantly, and the second phase particles coarsen during the process of atom migration. In addition, Micro-cracks and voids also come into being in the situation and they can become larger by combing each other during the creep process. At this stage, the growth of cavities and second phase particles coarsening become the main mechanism of creep damage. The trend of microstructural evolution is consistent with the creep constitutive equation obtained for the A508-III steel at the phase transition temperature of 800°C. The results obtained provide indispensable foundation to establish the relationship between the macroscopic creep and microscopic damage.
Investigation on Creep Behavior of Grade 91 Heat-Resistant Steel at 923K
Authors: Ren Fa Cai , Tang Xiao Ying
Published: October 2016

Creep deformation behavior of SA387Gr91Cl2 heat-resistant steel used for steam cooler has been investigated. Creep tests were carried out using flat creep specimens machined from the normalized and tempered plate at 973K with stresses of 100, 125 and 150MPa. The minimum creep rate and rupture time dependence on applied stress was analyzed. The analysis showed that the heat-resistant steel obey Monkman-Grant and modified Monkman-Grant relationships.
Study on the Non-Probabilistic Interval Damage of High Temperature Furnace Tube
Authors: Tian Yun , Zhou Chang Yu , Pan Lin Feng
Published: October 2016

Uncertainty of parameters like material mechanical properties are traditionally described by probabilistic model, which requires detailed statistical information of parameters limited to obtain in engineering application. In this paper, the problem is solved by using the non-probabilistic convex model that only needs the upper and lower bounds of variables instead of abundant statistical information, which greatly reduces the demand of data and avoids unsafe results caused by the scatter of data. Based on the non-probabilistic convex model, the non-probabilistic interval analysis method is introduced to calculate the creep damage of HK40 high temperature furnace tube and to discuss the influence of operation conditions on creep damage with operation pressure and operation temperature regarded as interval variables. Consequently, the effect of outer wall temperature on creep damage interval is greater at the beginning of furnace tube operation stage. With the increase of running time, the effect of inner wall temperature on creep damage interval is greater and greater, and at the same time greater than that of creep damage interval when the outer wall temperature considered as interval variables. When the operating pressure is treated as interval variable, the upper and lower bounds of creep damage are nearly in a straight line that indicates the effect of pressure change on damage is little. Meanwhile, the life of high temperature furnace tube is predicted according to the definition of non-probabilistic interval index, and the analysis results are compared with the results of probabilistic model. The analysis results sufficiently demonstrate that the non-probabilistic approach presented in this paper is viable.
Experimental Investigation on the Effect of Arm Length on Accuracy of Torque Wrench
Authors: Peng You Gang , Wang Yong
Published: October 2016

Experiments were carried out to investigate the effect of arm length on the accuracy of two typical conventional torque wrenches, namely, setting type torque wrench (STW) and indicating type torque wrench (ITW). The experiment results demonstrate that the measurement values of STW rises rapidly with decreasing arm length while measured torque of ITW shows irrelevant to arm length. Theoretical solution with respect to STW shows quite good agreement with experiment results. Irrelevance of arm length regard to ITW may be attributable to compensation of bending moment measurement due to proper arrangement of circuit and structural design. In order to conduct a proper assessment at a calibration laboratory or ensure its reliability with reference to actual use conditions, a torque wrench should be used by a customer at the loading point as recommended.
Efficient Analysis of 3D Mixed-Mode Cracks of a Pressure Vessel Based on Schwartz-Neuman Alternating Method
Authors: Du Qing , Shi Guang Yu
Published: October 2016

The Schwartz-Neuman alternating method is employed to analyze 3D cracks in structural components with complicated geometries.The SIFs of Mode I, II and III for the mixed-mode cracks under complicated stress state are obtained from the alternating computing scheme between finite element method solution for the uncracked body and the symmetric Galerkin boundary element method solution for the crack in an infinite body. The SIFs of the different surface cracks postulated at a regular pipe and elliptical surface cracks at the nozzle-cylinder intersection of a typical reactor pressure vessel are investigated by using the Schwartz-Neuman alternating method. The comparison with other analysis models and results reported in the literature shows that the Schwartz-Neuman alternating method can efficiently and accurately evaluate SIFs of surface cracks of different shapes and depths with much smaller computational models, which indicates that the Schwartz-Neuman alternating method is an efficient method in the evaluation of the SIFs of 3D cracks.
Effect of Maximum Temperature on the Thermal Fatigue Behavior of Superalloy GH536
Authors: Chen Jing , Shi Duo Qi , Miao Guo Lei , Yang Xiao Guang
Published: October 2016

Thermal fatigue tests of superalloy GH536 were carried out at different maximum temperature. Three-dimensional numerical finite element computations were performed to simulate thermal fatigue test process. The crack initiation, propagation and thermal fatigue failure mechanism of GH536 plate at different maximum temperatures were obtained by experiments and numerical methods. Result shows that the crack initiation life is shortened and the crack growth rate is accelerated with the increase of the maximum temperature of thermal fatigue test. The numbers of appearing 1 mm length cracks are 180, 74 and 37, respectively, when the maximum temperature is 800°C, 850°C and 900°C respectively. So the thermal fatigue performance decreases with the increase of the maximum temperature. But in the thermal fatigue tests of different maximum temperature, the thermal fatigue crack initiation is all caused by a single crack initiation source, and the thermal fatigue cracks initiate transgranularly, develop and propagate intergranularly.
Research on Full-Scale Hydrostatic Burst Testing of Different Pipeline Girth Weld Defects
Authors: Xuan Wen Bo , Wang Fu Xiang , Zhou Li Jian , Wang Ting , Chen Jian , Lei Zheng Qiang , Yang Hui
Published: October 2016

Recently incidents related to cracking of girth welds in oil and gas pipelines occurred frequently. With highly concentrated stresses, girth weld defects may significantly reduce bearing capacity of pipelines. Many girth weld defects were detected in the in-line inspection and excavated verification. How to assess the severity of these defects to avoid the excessive and unnecessary repair was a technical challenge. Four different kinds of girth weld defects were manufactured in the 32-inch pipeline and full-scale hydrostatic burst testing were carried out to assess the pressure performance of these defects. Many fitness-for-purpose assessment methods were applied to verify the accuracy of experimental results. After the testing, pipelines with failure defects were cut out to carry out the microanalysis. The research results make us understanding the severity of these defects and avoid the excessive and unnecessary repair of these defects to ensure the pipeline safety.
Structural Analysis and Optimization of Transition Section of Convex Tube Sheet
Authors: Liu Zun Chao , Wang Ke , Liu Tong , Xu Wei Feng , Liu Min Shan
Published: October 2016

The convex tube sheet which is used in heat recovery boiler consists of three parts: the high temperature tube sheet, the low temperature tube sheet and the transition section.Three-dimensional finite element model of convex tube sheet in new type of heat recovery boiler is established in this paper. Using the ANSYS Workbench software, thermal stress of the convex tube sheet is analyzed. The temperature fields and thermal stress distribution of convex tube sheet are obtained, and its structure strength is checked. The effects of the high temperature tube sheet thickness, low temperature tube sheet thickness and transition section thickness on the maximum equivalent stress of the convex tube sheet are analyzed. The results show that: temperature of most parts of convex tube sheet is close to the tube side fluid temperature, and the large temperature gradient only existed in the thinner regions of shell side of convex tube sheet; temperature distribution shows obvious skin effect. At the transition section, the temperature along the thickness direction is more evenly distributed, with little change in temperature gradient; larger thermal stress mainly concentrated at tube layout area which close to the shell side of the high temperature tube sheet and the connecting parts of transition section and low temperature tube sheet in the tube side. Through checking the strength intensity, convex tube sheet structural strength meets the requirements.The transition section thickness are optimized. The optimum thickness of the transition section analyzed in this paper is 31mm.
Semi-Open Thermal Protection Scheme of Electronics in Nuclear Rescue Robot
Authors: Sun Ke , Han Yan Long , Luan Wei Ling
Published: October 2016

Thermal management of electronics is quite important for safe operation of nuclear rescue robot. However, the ambient temperature of the nuclear robot in the site of nuclear accident will suffer an alternation between ordinary and elevated temperature. Traditional phase change material (PCM) based closed scheme for thermal protection is not suitable due to the capacity limitation of PCM. Open scheme with forced air cooling or water cooling is not acceptable either, because it cannot operate in high temperature. Therefore, a semi-open thermal control scheme is proposed by using silica aerogel for heat insulation, PCM for heat absorption, and Nickel-titanium alloy spring as temperature switch. An investigation on different ambient temperature, laying angle, melting point of PCM and heat power is conducted. The results showed that, compared with the PCM-based closed scheme, our design can provide 19.23% prolonged safe working hours, which can improve the reliability of electronic devices.
A Prediction Model for Mode-III Fatigue Crack Growth
Authors: Qi Shuang , Cai Li Xun , Shi Kai Kai , Bao Chen
Published: October 2016

In the fracture mechanics, the failure of mode-III crack belongs to the anti-plane shear (also called out-plane shear or longitudinal shear). Fatigue crack growth (FCG) behavior under mode-III reversed load (load ratio R=-1) was studied by using 30Cr2Ni4MoV rotor steel with types of circumferential notches. Under the remote cyclic torsional load, the precrack process was applied to specimens with notch in the round bar, and the ideal sharp-crack was obtained. Then, mode-III FCG test under the remote cyclic torsional load and the axial constant small load was carried out until to fatigue failure. The axial constant small load is aimed at reducing the cracks interaction in the mode-III FCG experiment. Due to experimental data of 30Cr2Ni4MoV rotor steel, the mode-III FCG rate in the range of KIII from 12MPa·m1/2 to 40 MPa·m1/2 and the threshold value were got. Furthermore, a prediction model for mode-III FCG is proposed with considering the small scale yield of plane stress crack tip zone and the plastic strain energy density failure criteria. The predicted mode-III FCG rate is found to agree well with the experimental curves of 30Cr2Ni4MoV rotor steel.
Failure Analysis of the outside Coating on the Furnace Roller
Authors: Feng Zheng Qu , Wang Lu , Wang Wei Ze , Cheng Kai Di , Chen Cheng Zhou
Published: October 2016

A failure case of the outside coating on the furnace roller is presented in this study. The coating consists of WC-Co, which is deposited on 45 steel by High Velocity Oxygen Fuel (HVOF) spraying. The spalling of coatings has been found in the middle of the roller. Rust was also observed on the coatings of the roller. The failure analysis of the coating was performed in terms of composition analysis, and microstructure observation etc. In addition, the effects of different sandblasting post-treatments were compared. And the effect of substrate material is investigated on the corrosion of coatings. It was concluded that the sandblasting particles remained on the substrate surface have effects on the failure of the coating. The peeling-off coating on the roller is also related with the formation of iron oxides. Less sand can be remained on the substrate surface when air purging and brushing is used after the sand-blasting compared with air purging or non-treatment is applied. The stainless steel shows more excellent corrosion resistance than the low carbon steel when they are used as substrate for WC-Co coatings.
HAZOP-LOPA-Based Corrosion Risk Identification and Control
Authors: Cong Guang Pei , Shi Xuan , Meng Ting Yu
Published: October 2016

It is analyzed to control the affection for dynamic affection of change in process parameters to the corrosion of equipment and pipes with the HAZOP, LOPA and corrosion self-healing control system, then HAZOP-LOPA–Based corrosion risk identification and control technology is proposed to improve the level of effective active control in high-risk corrosion in the petroleum–chemical process in this paper.
Comparative Study on the Application of Two RBI Methods on Pipelines
Authors: Chen Ding Yue , Chen Hu , Chen Wen Fei , Jin An Jie , Huang Huan Dong , Wang Du , Sheng Jian Ming , Qin Jing Fang
Published: October 2016

547 pipelines of SAN equipment of Ningbo X enterprise were independent evaluated by RBI technology using DNV`S Orbit Onshore software and method, and Lloyd's RBMI software and method.The probability offailure and failure consequence of pipeline were quantitative calculated by RBI technology and ultimately determined the risk matrix. From assumed condition set, damage modes analysis, failure probability and consequence,circuit divisionand risk matrix, the two RBI methods were comparative studied. Similarities and differences of two RBI methods were analyzed and optimalrisk matrixordering was get. It can provide scientific basis for the enterprise to carry out the risk-based inspection and not only improve the reliability of equipment but also reduce the cost.
Interaction between Local Plastic Strain and Multi-Scale Fatigue Crack Propagation Behavior in Titanium Alloy TC4
Authors: Ye Shen , Zhang Xian Cheng , Tu Shan Tung
Published: October 2016

Multi-scale Fatigue crack growth behavior of titanium alloy TC4 under different maximum stress was identified in the present work by using an in-situ fatigue testing system. Results showed that specimen tested at lower maximum stress exhibited longer fatigue life, since the small fatigue crack stage accounted for a larger fraction of the total fatigue life. Local deformation around fatigue crack was measured by digital image correlation (DIC) technique. The evolution of multi-scale fatigue crack was identified. Relationship between size of plastic zone and crack growth rate was identified.
Development of Bending and Torsion Fatigue Testing Machine for Multiaxial Non-Proportional Loading
Authors: Morishita Takahiro , Itoh Takamoto , Sakane Masao
Published: October 2016

This study presents a newly developed multiaxial high cycle fatigue testing machine which can load a cyclic bending loading and a reversed torsion loading onto an hour-glass shaped solid bar specimen. This testing machine can perform the fatigue tests with a high frequency under a proportional and a non-proportional loading conditions. In the non-proportional loading, principal directions of stress and strain are changed in a cycle. In the testing machine, the loading is generated by centrifugal force caused by the revolving weights attached to rotational wheels. The maximum frequency of the testing machine is 50Hz. A material tested was a type 304 stainless steel. In the test, two types of loading paths are employed, a proportional loading and a non-proportional loading. The former is a cyclic bending loading and the latter a combining cyclic bending and reversed torsion loading in the developed testing machine. In this study, an applicability of the testing machine is evaluated by carrying out the tests under these loading conditions.
A Modified Cumulative Damage Model for Fatigue Life Prediction under Variable Amplitude Loadings
Authors: Yue Peng , Lei Qiang , Zhang Cheng Lin , Zhu Shun Peng , Huang Hong Zhong
Published: October 2016

To evaluate the fatigue damage accumulation and predict the residual life of components at different stress levels, this paper proposed a modified cumulative damage model based on the strain energy density parameter. Noting that mean stress and load interaction under uniaxial fatigue loading exhibit significant effects on fatigue damage accumulation and life prediction. According to this, a new model based on damaged stress model which considers the effects of mean stress and load interaction was presented in this paper. The proposed model was verified by using four experimental data sets of aluminium alloys and steels. The experimental results are compared with those of the Miner’s rule, damaged stress model (DSM) and damaged energy model (DEM). Results show that the proposed model agrees better with the experimental observations than others.
Mechanical Behavior and Fatigue Performance of Carburized Steel Specimens
Authors: Pang Ke Ji , Yuan Huang
Published: October 2016

Carburization is popular in design and fabrication of mechanical parts, such as gears, to improve fatigue performance. However, it is still open how to characterize the mechanical property of carburized steel and to quantify effects of the carburization to fatigue life of carburized parts. In the present paper four types of specimens differently treated and carburized are experimentally investigated. The experiments confirm significant increments in hardness and yield stress due to carburization. The fracture strain of the carburized steel is significantly smaller than that of the base material. Although the fatigue performance of the carburized steel is slightly worse than the base material, the solid carburized specimen shows significantly longer fatigue life. The fatigue limit increases from ca. 300 MPa for the base material to 550 MPa for the tensile carburized specimens. Detailed measurements display that the carburized layer in a carburized specimen possesses high compressive residual stresses, which arises the fatigue performance of the carburized steel.
Weight Functions and Stress Intensity Factors for Eccentric through Cracks in a 3-D Rectangular Plate Subjected to In-Plane Loading
Authors: Hu Xu Teng , Jia Xu , Song Ying Dong
Published: October 2016

Three unknown coefficient weight functions for eccentric through cracks in a 3-D rectangular plate subjected to in-plane loading are proposed. 3-D finite element models of cracked rectangular plates within the whole range of crack aspect ratios, i.e., 0≤e/W≤0.8, 0.08≤a/(W-e)≤0.9, were established to obtain a reference SIF database for both crack points A and B, rather than 2-D finite element models. To improve the accuracy of the weight function, the coefficients were derived from this database using the Binary Lagrange Interpolation Method instead of Curve-Fitting Expression. Comparisons of stress intensity factors calculated using the present weight functions with finite element data for the high-order power law and residual stress distributions show high accuracy of the present weight functions.
Ductile Crack Growth Modeling under Low Cycle Fatigue Loading Condition
Authors: Nam Hyun Suk , Kim Yun Jae , Kim Jin Won
Published: October 2016

This paper presents a numerical method using FE damage analysis to simulate ductile tearing in CT specimen under low cycle fatigue loading conditions. To define a cyclic material properties, the nonlinear kinematic hardening model is adopted. The damage model is defined based on the ductility exhaustion concept using the multi-axial fracture strain energy concept. The proposed model is then applied to simulate two cyclic fracture toughness tests with different R-ratios. Simulated results show overall good agreement with experimental results.