bluuebunny/crossref_metadata_2025 huggingface dataset:
Clay mineral-grain size-calcite cement relationships in the Upper Cretaceous Chalk, UK: a preliminary investigation
Authors: Jeans C. V. , Tosca N. J . , Hu X. F. , Boreham S.
Published: May 2014

The idea is tested that the evolution of the Chalk’s clay mineral assemblage during diagenesis can be deduced by examining the relationships between its clay mineralogy, particle size distribution pattern, and the timing and trace element chemistry of the calcite cement. The preliminary results from five different examples of cementation developed at different stages of diagenesis in chalks with smectite-dominated clay assemblages suggest that this is a promising line of investigation. Soft chalks with minor amount of anoxic series calcite cement poor in Mg, Fe and Mn are associated with neoformed trioctahedral smectite and/or dioctahedral nontronite and talc. Hard ground chalk with extensive anoxic series calcite cement enriched in Mg and relatively high Fe, Mn and Sr are associated with neoformed glauconitesensu lato, berthierine and dioctahedral smectite, possibly enriched in Fe. The chalk associated with large ammonites shows extensive suboxic series calcite cement enriched in Mg, Mn and Fe that show no obvious correlation with its clay mineralogy. Nodular chalks with patchy suboxic series calcite cement enriched in Fe are associated with neoformed dioctahedral smectite, possibly enriched in Al, and berthierine. Regionally hardened chalk with extensive suboxic calcite cement and relatively high trace element contents contain pressure dissolution seams enriched in kaolin and berthierine. Laser-based particle-size distribution patterns suggest that each type of lithification has a typical complex clay mineral population, indicating that subtleties in mineralogy are not being identified and that there could be some control on the size and shape of the clay crystals by the different types of cementation.
Chemostratigraphy and provenance of clays and other non-carbonate minerals in chalks of Campanian age (Upper Cretaceous) from Sussex, southern England
Authors: Wray D. S. , Jeans C. V.
Published: May 2014

Geochemical analysis of acid-insoluble residues derived from white chalks and marl seams of Campanian age from Sussex, UK, has been undertaken. All display a broadly similar <2 μm mineralogical composition consisting of smectite or smectite-rich illite-smectite with subordinate illite and minor amounts of talc. Plots of K2O/Al2O3 and TiO2/Al2O3 indicate that most marl seams have an acid-insoluble residue composition which is slightly different to that of the over- and underlying white chalk, implying that marl seams are primary sedimentary features not formed through white chalk dissolution. On the basis of a negative Eu anomaly and trace element geochemistry one marl seam, the Old Nore Marl, is considered to be volcanically derived and best classified as a bentonite; it is considered to correlate with the bentonite M1 of the north German
succession.
Evidence of interspersed co-existing CaCO3-III and CaCO3-IIIb structures in polycrystalline CaCO3 at high pressure
Authors: Merlini M. , Crichton W. A. , Chantel J. , Guignard J. , Poli S.
Published: May 2014

New experimental data are reported on high-pressure polymorphism of CaCO3. The CaCO3-III phase was stabilized using a large-volume press device and high-resolution X-ray powder diffraction (XRPD) patterns were collected from a few mm3 of powder sample. The interpretation of XRPD indicates that CaCO3-III and CaCO3-IIIb structures are present simultaneously and are in similar proportions. The lack of any unindexed peaks demonstrates that these two polymorphs are the only phases in this experiment, indicating that CaCO3-III and CaCO3-IIIb are the structures most likely to occur above 2.5 GPa. Relevant co-axial crystallographic matrix transformations from lower-pressure polymorphs to both CaCO3-III and CaCO3-IIIb are discussed to illustrate a further possible occurrence of co-existing and interspersed stable polymorphs in carbonate systems.
A review of crystal chemistry of natural silicates of alkaline elements in the light of new structural data
Authors: Zubkova N. V. , Pekov I. V. , Pushcharovsky D. Yu.
Published: May 2014

A review is presented here of the crystal chemistry of natural silicates of alkaline elements, mainly Na, with a focus on reporting recent data on the structural mineralogy of the new members of this chemical family and their crystal structures. The majority of the natural hydrous silicates of alkaline elements studied are characterized by a specific crystal-chemical feature − the presence of silanol groups Si−OH. The discovery of the two new minerals, chesnokovite and yegorovite, means that all the main topological types of the [SixOy] complexes are represented in the crystal structures for this family.
Crystal-chemistry and short-range order of fluoro-edenite and fluoro-pargasite: a combined X-ray diffraction and FTIR spectroscopic approach
Authors: Della Ventura G. , Bellatreccia F. , Cámara F. , Oberti R.
Published: May 2014

This study addresses the crystal chemistry of a set of five samples of F-rich amphiboles from the Franklin marble (USA), using a combination of microchemical (Electron microprobe analysis (EMPA)), single-crystal refinement (SREF) and Fourier transform infrared (FTIR) spectroscopy methods. The EMPA data show that three samples fall into the compositional field of fluoro-edenite (Hawthorne et al., 2012), whereas two samples are enriched in high-charged C cations and – although very close to theCR3+boundary – must be classified as fluoro-pargasite. Magnesium is by far the dominant C cation, Ca is the dominant B cation (withBNa in the range 0.00−0.05 a.p.f.u., atoms per formula unit) and Na is the dominant A cation, withA☐ (vacancy) in the range 0.07−0.21 a.p.f.u.;WF is in the range 1.18−1.46 a.p.f.u. SREF data show that: TAl is completely ordered at the T(1) site; theM(1) site is occupied only by divalent cations (Mg and Fe2+);CAl is disordered between theM(2) andM(3) sites;ANa is ordered at the A(m) site, as expected in F-rich compositions. The FTIR spectra show a triplet of intense and sharp components at ~3690, 3675 and 3660 cm−1, which are assigned to the amphibole and the systematic presence of two very broad absorptions at 3560 and 3430 cm−1. These latter are assigned, on the basis of polarized measurements and FPA (focal plane array) imaging, to chlorite-type inclusions within the amphibole matrix. Up to eight components can be fitted to the spectra; band assignment based on previous literature on similar compositions shows thatCAl is disordered over theM(2) andM(3) sites, thus supporting the SREF conclusions based on the  bond distance analysis. The measured frequencies of all components are typical of O−H groups pointing towards Si−O(7)−Al tetrahedral linkages, thus allowing characterization of the SRO (shortrange- order) ofTAl in the double chain. Accordingly, the spectra show that in the fluoro-edenite/ pargasite structure, the T cations, Si and Al, are ordered in such a way that Si−O(7)−Si linkages regularly alternate with Si−O(7)−Al linkages along the double chain.
Thermal expansion inC2/cpyroxenes: a review and new high-temperature structural data for a pyroxene of composition (Na0.53Ca0.47)(Al0.53Fe0.47)Si2O6(Jd53Hd47)
Authors: Tribaudino M. , Mantovani L.
Published: May 2014

Single-crystal X-ray data collection was performedin situatT= 300 and 700°C on a sample synthesized along the jadeite–hedenbergite series. The structural data, together with those of a previous investigation of a crystal of the same composition, were compared to those of the endmembers. The evolution of the displacement parameters with temperature shows significant residuals for the O1, O2 and O3 oxygen atT= 0 K, most significantly in the O1, which were interpreted as an indication of positional disorder.

Volume thermal expansion and axial deformation ellipsoids were calculated for the above sample together with those of a series ofC2/cpyroxenes. Pyroxenes with a divalent M2 cation, Ca, Fe and Mg have a greater expansion than those with a monovalent M2, like Na and Li; the Na pyroxene endmembers with Al, Cr and Fe were observed to show greater expansion than corresponding Li ones.

The greater axial expansion is found along thebaxis, except in LiCrSi2O6; the changes along thebaxis are related to the volume thermal expansion. The axial orientation and anisotropy of the two axes onto the (010) plane is different in Na, Li and Ca-Mg-Fe pyroxenes, but the overall expansion onto the (010) plane, given by the sum of the scalar expansion along the two axes on (010), is very similar in pyroxenes.

The deformation along thebaxis with temperature and composition is driven by the deformation along b of the octahedral M1 chain; most important is the contribution from the O1−O1 shared edge between M1 octahedra in the same octahedral chain.
The crystal structure of sarmientite, Fe23+ (AsO4)(SO4)(OH)·5H2O, solved ab initio from laboratory powder diffraction data
Authors: Colombo F. , Rius J. , Vallcorba O. , Pannunzio Miner E. V.
Published: May 2014

The crystal structure of sarmientite, Fe23+ (AsO4)(SO4)(OH)·5H2O, from the type locality (Santa Elena mine, San Juan Province, Argentina), was solved and refined from in-house powder diffraction data (CuKα1,2 radiation). It is monoclinic, space group P21/n, with unit-cell dimensions a = 6.5298(1), b = 18.5228(4), c = 9.6344(3) Å, β = 97.444(2)º, V = 1155.5(5) Å3, and Z = 4. The structure model was derived from cluster-based Patterson-function direct methods and refined by means of the Rietveld method to Rwp = 0.0733 (X2 = 2.20). The structure consists of pairs of octahedral-tetrahedral (Fe−As) chains at (y,z) = (0,0) and (½,½), running along a. There are two symmetry-independent octahedral Fe sites. The Fe1 octahedra share two corners with the neighbouring arsenate groups. Both individual chains are related by a symmetry centre and joined by two symmetry-related Fe2 octahedra. Each Fe2 octahedron shares three corners with double-chain polyhedra (O3, O4 with arsenate groups; the O8 hydroxyl group with the Fe1 octahedron) and one corner (O11) with the monodentate sulfate group. The coordination of the Fe2 octahedron is completed by two H2O molecules (O9 and O10). There is also a complex network of H bonds that connects polyhedra within and among chains. Raman and infrared spectra show that (SO4)2− tetrahedra are strongly distorted.
Local order in wüstite using a pair distribution function (PDF) approach
Authors: Welberry T. R. , Goossens D. J. , Heerdegen A. P.
Published: May 2014

We show how different aspects of a model of the complex disordered structure of wüstite, Fe1−xO, affect the pair distribution function (PDF) and powder diffraction pattern. The aim is to assess the efficacy of using these techniques to determine details of local structure. The different aspects include the nature of the individual defect clusters, the nature of the paracrystalline superlattice on which they are distributed and the ‘size-effect’ relaxation of the basic rocksalt FeO matrix around the defects. The results show that PDF data are sensitive to those aspects of the models that have a significant effect on the populations of interatomic spacings but are less able to determine correlation structures in the samples if these do not have a substantial interaction with interatomic separations.
Solitary splenic metastasis of ovarian carcinoma: a case report
Authors: Karni Dror , Kopelman Doron , Hatoum Ossama Abu
Published: May 2014

Introduction

Splenic metastasis from ovarian carcinoma generally presents as peritoneal spread with multiorgan involvement. Fewer than 30 cases of solitary parenchymal splenic metastasis from ovarian carcinoma have been published in the literature. The presentation is often asymptomatic.

Case presentation

An increase in tumor marker CA-125 from 18.1 to 132.6 units/ml (normal <35 units/ml) was measured in a 56-year-old Israeli Jewish woman who had undergone, six years previously, a total abdominal hysterectomy with bilateral salpingo-oophorectomy due to right ovarian carcinoma. An abdominal computed tomography scan revealed a mass of 6×8cm at the anterior of the spleen, with close proximity to the wall of the stomach. A gastroscopy demonstrated exterior pressure on the stomach body. An open splenectomy was performed to exclude a peritoneal carcinomatosis. No intraoperative evidence of tumoral spreading in the abdominal cavity was observed, other than the spleen. The final histologic result demonstrated a high-grade carcinoma consistent with metastatic endometrioid-type ovarian carcinoma grade 3.

Conclusions

This case highlights the importance of cancer antigen 125 assessment and medical imaging in the follow-up of ovarian carcinoma. Open laparotomy, or laparoscopy, enables exclusion of a peritoneal carcinomatosis, which is more common than solitary parenchymal splenic metastasis, as was presented in the current case.
Mechanic’s hands revisited: is this sign still useful for diagnosis in patients with lung involvement of collagen vascular diseases?
Authors: Sohara Erei , Saraya Takeshi , Sato Shinji , Tsujimoto Naoki , Watanabe Takayasu , Takata Saori , Tanaka Yasutaka , Ishii Haruyuki , Takizawa Hajime , Goto Hajime
Published: May 2014

Background

The presence of “mechanic’s hands” is one of the clinical clues for collagen vascular diseases. However, the exact relevance of “mechanic’s hands” in collagen vascular diseases has not been well documented. The aim of this study was to clarify the relevance of “mechanic’s hands” to collagen vascular diseases including various skin lesions and interstitial pneumonia.

Methods

A retrospective review of the medical records of patients with “mechanic’s hands” at our hospital between April 2011 and December 2012 was conducted. A PubMed search was also conducted using the term “mechanic’s hands”.

Results

Four patients in our institution and 40 patients obtained from PubMed who had “mechanic’s hands” were identified. The most frequent diseases were DM/amyopathic DM (n = 24, 54.5%) and anti-ARS syndrome (n = 17, 38.6%). In these patients, the major skin lesions associated with “mechanic’s hands” were periungual erythema (n = 23, 52.3%), Gottron’s sign (n = 17, 38.6%), heliotrope rash (n = 10, 22.7%), Raynaud’s phenomenon (n = 9, 20.5%), and anti-ARS syndrome (n = 17, 38.6%). Six cases (2 DM, 4 anti-ARS syndrome) had only “mechanic’s hands”. Antibodies to anti-ARS (n = 24) were Jo-1 (n = 19), PL-7 (n = 3), OJ (n = 1), and PL-12 (n = 1).

Conclusion

The presence of “mechanic’s hands” together with diverse skin lesions could be a clinical clue to the diagnosis of lung involvement associated with collagen vascular diseases, especially in anti-ARS syndrome or DM/amyopathic DM.
Analysis of dose measurement other than the radiation protection during the radiographic examination
Authors: Kim Ki-Youl , Cho Jae-Hwan , Lee Hae-Kag
Published: May 2014

Objectives

The study measured the dose on body regions that were not shielded to protect from radiation exposure during the general procedure, with the goal of providing basic radiation dose data for radiological technologists who perform the radiographic examination.

Materials and methods

Shooting parts with the phantom were similar to human tissues using general shooting equipment in the general examination room. The scattered rays were measured with the ion chamber. The hand received the highest average radiation dose and the kidney the lowest. The same pattern was evident for the average equivalent dose. The available daily shooting was highest in the anterior/posterior skull, followed by the posterior/anterior chest, abdomen, anterior/posterior spine and extremities.

Results

The daily available numbers for the eye were lower than other body regions (6-times, 4-times, 26-times, 3-times and 121-times) and the numbers on the foot were higher than for other regions (73-times, 48-times, 263-times, 39-times and 702-times).

Conclusions

Radiation should be thoroughly blocked by the apron to protect the radiological technologist from the radiation exposure, the proper distance from the irradiation source should be maintained exposure is inevitable and the exposure dose and working environment shall be regularly assessed to ensure minimal exposure dose of the radiological technologist in accordance with the International Commission on Radiological Protection recommendation.
Combining the strength of genomics, nanoparticle technology, and direct intraductal delivery for breast cancer treatment
Authors: Teo Wei Wen , Sukumar Saraswati
Published: May 2014

A large number of genes are altered in cancer cells. Often, reversal or inhibition of just one of these alterations leads to death of the cancer cells. Technological advances in multiple areas are necessary to potentiate clinical translation of these findings. In a recent article, Brock and colleagues reported that overexpressed HOXA1 is a critical event in tumor progression in a mouse mammary tumor model. They developed HOXA1-small interfering RNA nanoparticles and achieved effective therapeutic doses by delivering them intraductally through the nipple to the site of the tumor and at the same time circumvented the systemic immune response. This study strengthens the concept of targeting overexpressed genes by using small interfering RNA and bypassing systemic immunity through local intraductal delivery.
Dma1-dependent degradation of Septation Initiation Network proteins during meiosis inSchizosaccharomyces pombe
Authors: Krapp Andrea , Simanis Viesturs
Published: May 2014

The Schizosaccharomyces pombe septation initiation network (SIN) is required for cytokinesis during vegetative growth and spore formation during meiosis. Regulation of the SIN during mitosis has been studied extensively, but less is known about its meiotic regulation. Here, we show that several aspects of the SIN regulation differ between mitosis and meiosis. First, the presence of GTP-bound spg1p is not the main determinant of the timing of cdc7p and sid1p association with the SPB during meiosis. Second, the localisation dependencies of SIN proteins differ from those in mitotic cells, suggesting a modified functional organisation of the SIN during meiosis. Third, there is stage-specific degradation of SIN components in meiosis; byr4p is degraded after meiosis I, while the degradation of cdc7p, cdc11p and sid4p occurs after the second meiotic division and depends upon the ubiquitin ligase dma1p. Finally, dma1p-dependent degradation is not restricted to the SIN, for we show that dma1p is needed for the degradation of mcp6p/hrs1p in meiosis I. Together, these data suggest that stage-specific targetted proteolysis will play an important role in regulating meiotic progression.
The Tor and Sin3-Rpd3 complex regulate expression of the mitophagy receptor protein Atg32
Authors: Aihara Masamune , Jin Xiulian , Kurihara Yusuke , Yoshida Yutaka , Matsushima Yuichi , Oku Masahide , Hirota Yuko , Saigusa Tetsu , Aoki Yoshimasa , Uchiumi Takeshi , Yamamoto Tadashi , Sakai Yasuyoshi , Kang Dongchon , Kanki Tomotake
Published: May 2014

When mitophagy is induced in Saccharomyces cerevisiae, the mitochondrial outer membrane protein ScAtg32 interacts with the cytosolic adaptor protein ScAtg11. ScAtg11 then delivers the mitochondria to the pre-autophagosomal structure for autophagic degradation. Despite the importance of ScAtg32 for mitophagy, the expression and functional regulation of ScAtg32 are poorly understood. In this study, we identified and characterized the ScAtg32 homolog in Pichia pastoris (PpAtg32). Interestingly, we found that PpAtg32 was barely expressed before induction of mitophagy and was rapidly expressed after induction of mitophagy by starvation. Additionally, PpAtg32 was phosphorylated when mitophagy was induced. We found that PpAtg32 expression was suppressed by Tor and the downstream PpSin3-PpRpd3 complex. Inhibition of Tor by rapamycin induced PpAtg32 expression, but could neither phosphorylate PpAtg32 nor induce mitophagy. Based on these findings, we conclude that the Tor and PpSin3-PpRpd3-related pathway regulates PpAtg32 expression, but not PpAtg32 phosphorylation.
Evidence-base for aspirin as venous thromboembolic prophylaxis following joint replacement
Authors: Jameson S. S. , Baker P. N. , Deehan D. J. , Port A. , Reed M. R.
Published: May 2014

The National Institute for Health and Clinical Excellence (NICE) has thus far relied on historical data and predominantly industry-sponsored trials to provide evidence for venous thromboembolic (VTE) prophylaxis in joint replacement patients. We argue that the NICE guidelines may be reliant on assumptions that are in need of revision. Following the publication of large scale, independent observational studies showing little difference between low-molecular-weight heparins and aspirin, and recent changes to the guidance provided by other international bodies, should NICE reconsider their recommendations?

Cite this article: Bone Joint Res 2014;3:146–9.
Thermal stability of novel polyurethane adhesives investigated by TGA
Authors: Maminski Mariusz , Jaskolowski Waldemar , Parzuchowski Pawel
Published: May 2014

The objective of the work was an assessment of thermal stability of novel polyurethane wood adhesives by means of TGA. Hyperbranched polyglycerols of various structures were used as polyol components cured with polymeric methylenediphenyldiisocyanate (PMDI) or polymeric hexamethylenediisocyanate (PHDI). Resultant adhesives were thermally degraded in temperature range 20 - 500ÂºC. Performance of polyurethane based on fully aliphatic polyglycerol was inferior to those based on polyglycerols bearing aromatic moieties. The differences in 50%-weight loss temperature achieving 27 - 39Â°C as well as residual weights at 480 ÂºC indicate the contribution of aromatic units presence within the macromonomer structure to increased thermal stability of polyurethane upon thermal degradation. Furthermore, temperature of 50% weight loss revealed that thermal stability of the developed hyperbranched polyglycerol-based adhesives was comparable to that of the commercial PUR adhesive.
Photoelectrochemical Studies on Inorganic/Organic Aqueous Nano-Suspensions Made by TiO2/Poly Neutral Red Assembly
Authors: K. Kasem Kasem , Bennett William
Published: May 2014

An inorganic/organic interface (IOI) consisting of TiO2/polyNeutral Red(PNR) was subjected to photoelectrochemical studies in both aqueous nano-suspensions and in thin solid forms. The effects caused by PNR modifier on the photoelectrochemical behaviour of the IOI were investigated using [Fe(CN)6]4- as a photoactive hydrated electron donor agent. Results show that the adsorption process of [Fe(CN)6]3- (photolysis product) controls the photo-activity outcomes of IOI assemblies. TiO2/PNR shows lower heterogeneous photochemical response than native TiO2 in a short photolysis time. At longer photolysis times the IOI show a photo activity greater than that of native TiO2. TiO2 /PNR nanoparticles adsorb more [Fe(CN)6]3- in a very steady adsorption /desorption process than the unmodified particles. The interface activities were explained by analysing the IOI junction characteristics, such as electron affinity, work function and hole/electron barrier heights. At TiO2/PNR a strong hybridization between electrons-like and hole-like sub band states in close vicinity to the Fermi energy are developed. The aqueous nano-systems retained moderate stability as indicated by the reproducibility of their photo catalytic activities. Both [Fe(CN)6]4- and PNR contributed to the stability of native TiO2 surfaces.
A Remark on Newest Vertex Bisection in Any Space Dimension
Authors: Gallistl Dietmar , Schedensack Mira , Stevenson Rob P.
Published: May 2014

With newest vertex bisection, there is no uniform bound on the number of n-simplices that need to be refined to arrive at the smallest conforming refinement

𝒯
'

$\mathcal {T}^{\prime }$

of a conforming partition

𝒯

$\mathcal {T}$

in which one simplex has been bisected. In this note, we show that the difference in levels between any

T
'

∈

𝒯
'

$T^{\prime } \in \mathcal {T}^{\prime }$

and its ancestor

T
∈
𝒯

$T \in \mathcal {T}$

is uniformly bounded.
This result has been used in
Lemma 4.2 of [SIAM J. Numer. Anal. 51 (2013), 2935–2955]
by Carstensen and the first two authors.
Analytic in planar domains functions with preassigned asymptotic set
Authors: Ganenkova Ekaterina G. , Starkov Victor V.
Published: May 2014

In 1954 M. Heins proved that, for every
analytic set A containing the infinity, there exists an entire
function whose set of asymptotic values at the infinity equals A.
We obtain analogs of this result for functions analytic in planar
domains of arbitrary connectivity.
Freeze-Thaw-Cycles on Borehole Heat Exchanger Grouts: Impact on the Hydraulic Properties
Authors: Anbergen Hauke , Frank Jens , Müller Lutz , Sass Ingo
Published: May 2014

In this paper a testing device is described that measures the hydraulic conductivity of grout specimens for Borehole Heat Exchangers (BHE). During the operation of closed-loop ground source heat pumps running with antifreeze, freezing of the backfill can occur due to extensive heat extraction. This laboratory device can assess the influence of frost on the hydraulic seals of BHEs. The device is based on a triaxial flexible wall permeameter. A freely selectable number of cyclic freeze-thaw-stresses as well as a confining pressure simulating radial earth pressure (σ2 = σ3) can be applied. Specimens are composed of an annular grout body and a polyethylene pipe simulating the BHE system. The freezing direction is perpendicular to the vertical axis of the BHE from the inside to the outside. Numerical coupled modeling was applied to verify the results of the temperature distribution inside the specimens. It was observed and modeled that the propagation of the frost front and the fabric disintegration processes are correlated. Results of three different grouting materials will be presented. With its relative small dimensions the device can be easily implemented into soil mechanical laboratories and thus can contribute to quality control of grouts.
Improved Isotropically Consolidated Undrained Triaxial Test Method for Non-Self-Supporting Materials
Authors: Zhu Wei , Wang Rui , Zuo Jia , Lin Cheng , Min Fanlu
Published: May 2014

The non-self-supporting materials that are often encountered in practice include shield tunnel grout, cement mortar, mine tailings, and dredged sludge. These materials typically have characteristics of high moisture content and high flowability. So far, a complete mechanical process (e.g., consolidation and shearing) of the non-self-supporting materials has not been well characterized because the materials of high flowability cannot be tested directly in conventional triaxial test equipment. This paper presents an improved triaxial test method capable of preparing the flowable specimens and testing them in a conventional triaxial apparatus. The procedure includes: (1) a flowable specimen prepared in the split mold and forced to be erective through a small confining pressure applied to the holes built in the split mold, (2) the split mold was detached from the specimen using the specially designed components and remained in the triaxial cell, and (3) the specimen was then subjected to the consolidation and shearing test. The improved triaxial test method was used to test the shield tunnel grout, dredged sludge, and the dry sand in an isotropically consolidated undrained shear condition. The test results indicated the improved triaxial method was used successfully to simulate the stress–strain behavior of the non-self-supporting materials in a holistic manner.
Comparison of True Triaxial and Hollow Cylinder Tests on Cross-Anisotropic Sand Specimens
Authors: Lade Poul V. , Rodriguez Nina M.
Published: May 2014

Experiments have been performed in true triaxial equipment and in hollow cylinder equipment on dense Fine Nevada sand to study and compare the influence of the intermediate principal stress on the behavior observed in the two types of apparatuses. By suitable application of outside and inside pressures in hollow cylinder tests performed on cross-anisotropic sand deposits with horizontal bedding planes (without application of shear stresses), generated stress states are comparable with those applied in true triaxial tests on oriented specimens in Sector I and III of the octahedral plane. Stress non-uniformities occur in the hollow cylinder specimens and they may affect the results of these tests. The experiments showed good comparison in Sector I, but those in Sector III were not comparable because the hollow cylinder tests showed effects of buckling instability, failure in the σ2-direction, and effects of stiff versus flexible boundaries through which the pressures were applied.
Alternatives for the Detection of Residual Polyacrylamide in Geotextile Tube Dewatering—Streaming Current Detection and China Clay Settling Rate Methods
Authors: Bhatia Shobha K. , Khachan Mahmoud M. , Stallings Andrew M. , Smith Jennifer L.
Published: May 2014

The use of polyacrylamide (PAM)-based flocculants has become an essential component of most geotextile tube dewatering projects. Although knowledge of the residual flocculant concentration in geotextile tube supernatant and effluent is essential to the safe use of PAM-based flocculants, residual flocculant concentration is not commonly measured in geotextile tube dewatering operations. Furthermore, there is no ASTM standard test method for measuring residual flocculant concentrations in water. This paper presents a comparative study of two different methods that are commonly used to measure residual flocculant concentrations in water: the Streaming Current Detection (SCD) method and the China Clay Settling Rate (CCSR) method, to evaluate their applicability to the geotextile tube industry. The comparison is based on an analysis of measured residual PAM concentrations obtained for five different cationic PAM polymers used to flocculate Tully fines soil. Optimum flocculant doses for the Tully fines soil were determined using the jar test (ASTM D2035-08) for three different solids concentrations by mass (5, 15, and 33 %). The SCD and CCSR methods were performed on the supernatants of Tully fines that were conditioned at their optimum doses and at concentrations 50 % above their optimum dose. Laboratory test results showed that both the SCD and CCSR methods produced similar residual PAM concentration results for the polymer/soil combinations tested. The SCD method, however, produced more consistent and repeatable results in comparison to the CCSR method. The SCD method was also easier to use and could be performed in shorter amounts of time than the CCSR method. Based on the results, it is recommended that the SCD method be standardized and used to measure residual PAM-based flocculant concentrations in geotextile tube supernatant and effluent.
Centrifuge Modelling of Diaphragm Wall Construction Adjacent to Piled Foundations
Authors: Choy C. K. , Standing J. R. , Mair R. J.
Published: May 2014

Diaphragm walls are often implemented to support the sides of deep excavations and in urban environments situations increasingly occur where it is necessary to install them close to existing piled structures. There is a lack of good quality field monitoring case studies to help understand this complex three-dimensional soil–structure interaction problem. It can be investigated using numerical analysis or an alternative approach is to perform small-scale model tests in a geotechnical centrifuge. This paper describes a sophisticated model construction system that was developed to simulate the construction sequence (excavation and casting of concrete) of a single or series of three diaphragm wall panels in sand as part of a study to investigate the influence of constructing diaphragm walls adjacent to piled foundations. Prior to wall construction an adjacent instrumented model pile was driven in-flight and a constant force maintained at the pile head to simulate axially loaded piles. The system response was captured through the use of miniature soil stress cells, LVDTs, and laser displacement sensors. A detailed description of the centrifuge model and test procedures developed is presented and the necessary simplifications and associated errors discussed. The effectiveness of the small-scale physical model is demonstrated by presenting some selected test results (soil stresses and deformations).
Discussion of “Atterberg Limits and Remolded Shear Strength—Water Content Relationships”
Authors: Prakash K. , Sridharan A.
Published: May 2014

The present discussion tries to bring out the importance of clay mineralogical composition of fine-grained soils on their liquid limit behaviour. It reinforces the author's observation that the undrained shear strengths at liquid limit water content and at plastic limit water content are not unique.
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

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

The 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

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

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

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

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

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

Quenching 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

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.