bluuebunny/crossref_metadata_2025_split huggingface dataset:
Closure to Discussion by K. Prakash and A. Sridharan of “Atterberg Limits and Remolded Shear Strength–Water Content Relationships” [Geotechnical Testing Journal, Vol. 36, No. 6, pp. 939–947]
Authors: O’Kelly Brendan C. 
Published: May 2014

Abstract
This article presents the closure to the discussion on the Geotechnical Testing Journal, GTJ20130012, Vol. 36, No. 6, which had three stated objectives: (i) a critical assessment of empirical methods for predicting remolded undrained strength (sur) at different water contents on the basis of measured Atterberg limit values; (ii) a review of sur values mobilized at the Casagrande liquid limit (LL) and plastic limit (PL) conditions and hence the strength variation over the plastic range; and (iii) a new approach was propose for predicting sur values mobilized at different water contents. The original article stated the importance of clay mineralogy on clay behavior. A referenced comment was made regarding discourse by other researchers in recent literature on the link between mineralogy and differences in strengths at LL determined using the Casagrande cup and fall cone approaches. Although outside the immediate scope of the original article, this closure presents the opportunity to elaborate on this discourse since specifically raised by the discussers. The discussers also raised an unrelated but important point, namely attempts by several researchers of late to determine the PL using variants of the fall cone method. The author concurs with the discussers that these approaches deduce a strength-related reference water content that is fundamentally different from the lower water content limit for soil workability, which the Casagrande PL can be considered.
Impact of Different Loading Patterns with Short Duration on the Permanent Strain of Asphalt Mixture
Authors: Mansourkhaki Ali , Sarkar Alireza , Ameri Mahmoud 
Published: May 2014

AbstractThe suggested procedure for measuring the permanent deformation of asphalt concrete mixtures in the standard laboratory tests are based on using a single-hump loading. This loading type can only simulate the single-axle load, whereas pavements are subjected to single, tandem, and tridem axles at different speeds. On the other hand, the behavior of asphalt mixtures is affected by the loading pulse duration as a function of moving speed. Therefore, the laboratory investigation of permanent deformation is more logical under similar loading conditions. Accordingly, in this study, the effect of the type and duration of loading on the permanent strain of asphalt mixture have been examined at three stress levels. To investigate, the unconfined cyclic creep test was performed on asphalt specimens and, finally, the impacts of each variable on the permanent strain were evaluated, as discussed here in detail. Based on the findings of this research, it is concluded that for various loading patterns, the permanent deformation caused by the tridem axles can be greater than that caused by single and tandem axles, and under tandem axles it can be greater than that under single axles; the effects are dependent on the loading duration indeed. Also, this study showed that the impact of pulse duration on the changing trend of permanent strain is dependent on loading pattern and stress level.
Creep-Fatigue-Environment Crack Tip Kinetics of Ni-Base Superalloys
Authors: Evans Jeffrey L. 
Published: May 2014

Abstract
Several time-dependent damage mechanisms can operate during creep-fatigue loading. In the crack tip region, creep deformation, stress relaxation, oxygen diffusion along grain boundaries, and grain boundary oxidation are all occurring during the hold period of a creep-fatigue cycle. These conditions can lead to grain boundary embrittlement; however, it depends on the rates of the different processes. A comparison of the kinetics can determine which mechanisms are operational and which mechanism is the rate limiting step in the time-dependent damage process during creep-fatigue crack growth. This paper presents results for intergranular embrittlement occurring within a 10 s hold period and compares the kinetics of the processes.
Fatigue Behavior of Nickel Based Super Alloy 718 in a Hot Corrosive Environment
Authors: Prakash Raghu V. , Dhinakaran Sampath , Venkata Ramakanth Jeyar , Paulose Neeta , Narendrababu S. N. , Mannan S. L. 
Published: May 2014

Abstract
Nickel based super-alloys when exposed to a combination of high temperature and low melting point fused corrosion products, result in early fatigue failure compared to their response in high temperature benign environment. The high cycle fatigue (HCF) (at 550 and 625°C) as well as fatigue crack growth (at 550°C) behavior of a nickel based super alloy 718 in hot corrosive environment (Na2SO4+NaCl salt coating), typical of marine engine environment, is presented in this paper. At least an order of magnitude decrease in fatigue life is noticed when the temperature is changed from 550 to 625°C at stress levels below 450 MPa. The statistical analysis of scatter in fatigue lives at different stress levels is performed and a Weibull–Inverse power law model is fitted to the stress–fatigue life data of alloy 718 in hot corrosive environment. Fracture surface examination of hot corrosion fatigue failures showed higher crack growth rates compared to uncoated high temperature HCF fracture surfaces. Fatigue crack growth rate at 550°C in a hot corrosive environment increases by an order of magnitude at 0.5 Hz in the Paris region compared to crack growth kinetics at 2 Hz in lab air environment at the same temperature. The fracture surface shows a mix of transgranular and intergranular mode of crack in the propagation region at 0.5 Hz. A fatigue failure diagram is proposed combining the thresholds of maximum stress level from endurance tests and maximum stress intensity factor from fatigue crack growth tests to demarcate the regions of propagating and non-propagating cracks during hot corrosion fatigue. The complexities in incorporating the effect of loading frequency in fatigue failure diagram are highlighted.
Towards the Development of a Physics-Based Thermo-Mechanical Fatigue Life Prediction Model for a Single Crystalline Ni-Base Superalloy
Authors: Amaro Robert L. , Antolovich Stephen D. , Neu Richard W. , Adair Benjamin S. , Hirsch Michael R. , Fernandez-Zelaia Patxi , O'Rourke Matthew , Staroselsky Alexander 
Published: May 2014

Abstract
A long term effort has been underway to develop a mechanism-based model for life prediction under thermo-mechanical fatigue (TMF) cycling. A model has been developed which is based upon the impingement of slip bands upon oxidized regions and subsequent initiation of a crack due to stress concentration. The concept of an effective cycle temperature, T eff, and the dynamic nature of the material are critical components of the model and result in the ability to produce very accurate life predictions. It has also been shown that the model is capable of addressing complexities such as imposed high cycle fatigue (HCF) while still producing excellent agreement with the experiment. However, given the fact that this material is used for jet engine turbine blades and that such blades have cooling holes which act as notches, the next step in the development of this model is to incorporate it into a notched environment. The principal features of the TMF model are reviewed and a strategy for full integration into notched fatigue life prediction is discussed. Recent experimental results are presented which are based upon simulating smooth bar conditions at the notch root and a first approach to numerical simulation (called Q fit) is presented. Suggestions for further research are discussed.
Creep-Fatigue Interaction Models for Grade 91 Steel
Authors: Holmström Stefan , Pohja Rami , Payten Warwick 
Published: May 2014

Abstract
Different approaches for modelling creep–fatigue (CF) interaction are used on strain controlled creep fatigue data of 9Cr–1Mo-VNb (P91) steel and assessed with the target of finding suitable candidates for use in design rules. The assessed models include time, ductility, and strain energy-based creep-fatigue interaction methods and two simplified models. For the interaction diagram-based models, the challenge of acquiring representative creep damage fractions from the dynamic material response, i.e., cyclic softening with changing relaxation behaviour is addressed. In addition, the interaction diagram approaches are discussed in the light of known (fatigue) material scatter and defining representative cycles for CF data. The performance of the model are presented and also compared against the RCC–MR design code methodology. It is shown that the fitting accuracy of the complex interaction models vary significantly and that modified ductility based models seem to be less susceptible to changes in supporting creep and relaxation models. Successful and also superior prediction of the CF number of cycles to failure for Grade 91 steel was accomplished by simplified methods with much less fitting parameters. The practicality in using interaction diagram methods for design purposes, where simplicity is a key issue, is questioned.
Approach for Stabilized Peak/Valley Stress Modeling of Non-Isothermal Fatigue of a DS Ni-Base Superalloy
Authors: Bouchenot Thomas , Gordon Ali P. , Shinde Sachin , Gravett Phillip 
Published: May 2014

Abstract
Turbine blades derived from directionally solidified (DS) Ni-base superalloys are increasingly employed in the first and second stages of gas turbine engines, where thermal and mechanical cycling facilitate cyclic plasticity and creep. The elongated grains, which are aligned with the primary stress axis of the component, provide (1) greater creep ductility, and (2) lower minimum creep rate in solidification direction compared to other directions. Tracking the evolution of deformation in these structures necessitates a constitutive model having the functionality to capture rate, temperature, history, and orientation dependence. Historically, models rooted in microstructurally based viscoplasticity simulate the response of long-crystal, dual-phase, Ni-base superalloys with extraordinary fidelity; however, a macroscopic approach having reduced order is leveraged to simulate low-cycle fatigue (LCF), creep, and creep-fatigue responses with equally high accuracy. This study applies uncoupled creep and plasticity models to predict the thermomechanical fatigue (TMF) of a generic DS Ni-base, and an anisotropic yield theory accounts for transversely isotropic strength. The microstructure of the subject material contains γ-matrix (FCC Ni) and γ′-particles (cuboidal Ni3Al). Because of the fully analytic determination of material constants from mechanical test data, the model can be readily tuned for materials in either peak- or base-loaded units. Application of the model via a parametric study reveals trends in the stabilized hysteresis response of under isothermal fatigue, creep fatigue, idealized thermomechanical fatigue, and conditions representative of in-service components. Though frequently considered in design and maintenance of turbine materials, non-isothermal fatigue has yet to be accurately predicted for a generalized set of loading conditions. The formulations presented in this study address this knowledge gap using extensions of traditional Ramberg-Osgood and Masing models.
Current Investigations at Quenching Research Centre
Authors: Liščić Božidar , Filetin Tomislav , Landek Darko , Župan Josip 
Published: May 2014

AbstractQuenching Research Centre (QRC) was established at the beginning of 2010 through the financial support for excellence of the Ministry of Science Education and Sport, of the Republic of Croatia. The main investigation and research possibilities and potentials of the QRC are: quenching in liquids or in a salt bath and cooling by high pressure gases. As a result of long term research, the Temperature Gradient System has been designed, together with a unique cylindrical probe of 50 mm diameter by 200 mm instrumented with three thermocouples. Another device used at the Centre was the IVFSmartQuench® system according to ISO 9950, using a quenching device with agitation according to the ASTM D6482 standard. That equipment is used to investigate liquid quenchants and process parameters, including development of new quenchants: water, oil, and polymer based nanofluids, agitated by ultrasonic vibrations as a novel technology. QRC is also equipped with unique high pressure gas quenching facilities, providing the hardware for controllable heat extraction. The aim of using that equipment is to develop the method for measuring hardenability of high-alloyed steels when they are gas quenched and where a Jominy test is not applicable. QRC is also one of the initiators and an active participant in the project Global database on cooling intensities of liquid quenchants, which is coordinated and conducted by International Federation for Heat Treatment and Surface Engineering (IFHTSE).
Induction Hardening—Establishing the Process Window for Induction Quenching by Using Experimental Results and Computational Tools
Authors: Stormvinter Albin , Kristoffersen Hans , Troell Eva 
Published: May 2014

Abstract
To establish the process window for the spray quenching step of the induction hardening process is essential for quality control and optimized use of the quenching capacity supplied by the quenching unit. In general, the process window is established by an empirical approach, where the processing is related to the mechanical properties. On the other hand, there has been a rapid development of computational tools that may facilitate and accelerate process optimization. In the present work it is demonstrated how such tools, e.g., FE-simulation and multivariate analysis, can be applied to couple quenching characteristics to mechanical properties. The methodology is applied to induction hardened steel cylinders that were quenched with different flow rates, temperatures and composition of the quenchant. The results show how mechanical properties can be related to characteristics of the quenching, e.g., heat transfer coefficients and characteristics of the cooling curve. Moreover, the work discusses and exemplifies how the process window can be established and how computational tools allow the user to virtually alter the processing and estimate the impact it may have on the mechanical properties.
A Prediction of Quenching Parameters Using Inverse Analysis
Authors: Landek Darko , Župan Josip , Filetin Tomislav 
Published: May 2014

Abstract
The cooling curves of still water and of water-based polymer quenchant polyalkylene glycol (PAG) were recorded with the ISO Inconel 600 probe with 12.5 diameter and 60 mm length equipped with a type K thermocouple inserted into the probe's geometric center. The research included recording of cooling curves for still water in temperature range from 20 to 60°C, as well as quenching experiments with water based polymer solutions with concentration from 10 to 30 vol. % of PAG. The possibility of a new cooling curve determination method for any given water temperature based on interpolation model and experimental data for cooling curves at three different water temperatures was tested. Surface temperature, heat flux density, and heat transfer coefficient (HTC) were estimated based on the recorded cooling curve at the center of the ISO Inconel 600 probe using the solutions of inverse heat conduction problem (IHCP). The results of the inverse heat transfer analysis of the ISO Inconel 600 probe cooling in water and water based polymer solutions were compared to the results of the commercial software ivf SQintegra ver4.0 for the same cooling experiments. The proposed inverse determination of HTC can be used for the specification of boundary conditions in numerical simulations of quenching axisymmetric work pieces with similar dimensions to the ISO Inconel 600 probe.
Ductility and Brittleness in Rotating Disc Cavitation Erosion Testing
Authors: Meged Y. 
Published: May 2014

Abstract
Ductile and brittle failures have been long detected in metallic specimens when tested in tensile and impact tests. Recent observations indicate that these failures occur in cavitation erosion tests as well. Brittle failures in cavitation erosion tests take place under high cavitation loads, especially in rotating disc (RD) rigs. In the framework of the international cavitation erosion test (ICET), 264 tests were performed using seven test methods. One of these methods, the RD, proved to exert the highest cavitation erosion load on the test specimens, resulting in 29 brittle failures in 50 tests. The high percentage of brittle failures called for a close study of this failure mode, as detected in testing of five ICET reference metallic materials. In some cases, areas in the erosion-time domain were located, in which the ductile-to-brittle transition is highly probable.
Salvaging hope: Is increasing NAD+ a key to treating mitochondrial myopathy?
Authors: Lightowlers Robert N , Chrzanowska‐Lightowlers Zofia MA 
Published: May 2014

Mitochondrial diseases can arise from mutations either in mitochondrial DNA or in nuclear DNA encoding mitochondrially destined proteins. Currently, there is no cure for these diseases although treatments to ameliorate a subset of the symptoms are being developed. In this issue of EMBO Molecular Medicine, Khan et al () use a mouse model to test the efficacy of a simple dietary supplement of nicotinamide riboside to treat and prevent mitochondrial myopathies.
The Set1/COMPASS Histone H3 Methyltransferase Helps Regulate Mitosis With the CDK1 and NIMA Mitotic Kinases in Aspergillus nidulans
Authors: Govindaraghavan Meera , Anglin Sarah Lea , Osmani Aysha H , Osmani Stephen A 
Published: May 2014

Abstract
Mitosis is promoted and regulated by reversible protein phosphorylation catalyzed by the essential NIMA and CDK1 kinases in the model filamentous fungus Aspergillus nidulans. Protein methylation mediated by the Set1/COMPASS methyltransferase complex has also been shown to regulate mitosis in budding yeast with the Aurora mitotic kinase. We uncover a genetic interaction between An-swd1, which encodes a subunit of the Set1 protein methyltransferase complex, with NIMA as partial inactivation of nimA is poorly tolerated in the absence of swd1. This genetic interaction is additionally seen without the Set1 methyltransferase catalytic subunit. Importantly partial inactivation of NIMT, a mitotic activator of the CDK1 kinase, also causes lethality in the absence of Set1 function, revealing a functional relationship between the Set1 complex and two pivotal mitotic kinases. The main target for Set1-mediated methylation is histone H3K4. Mutational analysis of histone H3 revealed that modifying the H3K4 target residue of Set1 methyltransferase activity phenocopied the lethality seen when either NIMA or CDK1 are partially functional. We probed the mechanistic basis of these genetic interactions and find that the Set1 complex performs functions with CDK1 for initiating mitosis and with NIMA during progression through mitosis. The studies uncover a joint requirement for the Set1 methyltransferase complex with the CDK1 and NIMA kinases for successful mitosis. The findings extend the roles of the Set1 complex to include the initiation of mitosis with CDK1 and mitotic progression with NIMA in addition to its previously identified interactions with Aurora and type 1 phosphatase in budding yeast.
Effects of the Implant Design on Peri‐Implant Bone Stress and Abutment Micromovement: Three‐Dimensional Finite Element Analysis of Original Computer‐Aided Design Models
Authors: Yamanishi Yasufumi , Yamaguchi Satoshi , Imazato Satoshi , Nakano Tamaki , Yatani Hirofumi 
Published: May 2014

Background: Occlusal overloading causes peri‐implant bone resorption. Previous studies examined stress distribution in alveolar bone around commercial implants using three‐dimensional (3D) finite element analysis. However, the commercial implants contained some different designs. The purpose of this study is to reveal the effect of the target design on peri‐implant bone stress and abutment micromovement.Methods: Six 3D implant models were created for different implant–abutment joints: 1) internal joint model (IM); 2) external joint model (EM); 3) straight abutment (SA) shape; 4) tapered abutment (TA) shapes; 5) platform switching (PS) in the IM; and 6) modified TA neck design (reverse conical neck [RN]). A static load of 100 N was applied to the basal ridge surface of the abutment at a 45‐degree oblique angle to the long axis of the implant. Both stress distribution in peri‐implant bone and abutment micromovement in the SA and TA models were analyzed.Results: Compressive stress concentrated on labial cortical bone and tensile stress on the palatal side in the EM and on the labial side in the IM. There was no difference in maximum principal stress distribution for SA and TA models. Tensile stress concentration was not apparent on labial cortical bone in the PS model (versus IM). Maximum principal stress concentrated more on peri‐implant bone in the RN than in the TA model. The TA model exhibited less abutment micromovement than the SA model.Conclusion: This study reveals the effects of the design of specific components on peri‐implant bone stress and abutment displacement after implant‐supported single restoration in the anterior maxilla.
Botanical Investigation of Fallopia Dumetorum (L.) Holub (Polygonaceae) and Qualitative and Quantitative Assessment of its Polyphenolic Compounds
Authors: Olaru Ot , Ancuceanu Rv , Anghel Adriana Iuliana , Dinu Mihaela , Seremet Oana Cristina , Istudor Viorica 
Published: May 2014

Abstract
Background: Considering the continuous need to find new sources of polyphenolic compounds, we performed a pharmacognostical examination of the species Fallopia dumetorum (L.) Holub sin. Polygonum dumetorum L. (Polygonaceae). The plant is common in the plain regions of Romania and has not been exploited therapeutically.
Materials and method: Microscopic examination was performed on cross-sections, surface preparations and on powder obtained from the aerial parts of the flowering plant. Qualitative chemical analysis was realized by phytochemical screening and thin layer chromatography (TLC). Phenolic compounds were assayed by spectrophotometric methods: flavonoids expressed as rutin (with aluminium chloride), phenolcarboxylic acids expressed as chlorogenic acid (Arnow’s method) and proanthocyanidins expressed as cyanidin chloride (in acidic medium, by conversion to anthocyanins).
Results: The species has the following microscopic characters: anomocytic stomata, druses of calcium oxalate, sessile, pluricellular glandular hairs and pollen grains with smooth exine. Polysaccharides, reducing compounds, coumarins, sterols/triterpenes, phenol-carboxylic acids, flavones, proanthocyanidins, tannins and carotenoids were identified by phytochemical screening; chlorogenic acid, caffeic acid, quercetin and stigmasterol/beta-sitosterol were detected by TLC. F. dumetori herba has a content of 1.49 ± 0.105 g% polyphenol-carboxylic acids, 0.40 ± 0.087g% flavonoids and 0.18 ± 0.002 g% proanthocyanidins.
Conclusions: We have characterized pharmacognostically the native species F. dumentorum. Due to its content in phenolic compounds it might serve as a source of polyphenols.