bluuebunny/crossref_metadata_2025 huggingface dataset:
Controls on recent Alaskan lake changes identified from water isotopes and remote sensing
Authors: Anderson Lesleigh , Birks Jean , Rover Jennifer , Guldager Nikki
Published: June 2013

High‐latitude lakes are important for terrestrial carbon dynamics and waterfowl habitat driving a need to better understand controls on lake area changes. To identify the existence and cause of recent lake area changes in the Yukon Flats, a region of discontinuous permafrost in north central Alaska, we evaluate remotely sensed imagery with lake water isotope compositions and hydroclimatic parameters. Isotope compositions indicate that mixtures of precipitation, river water, and groundwater source ~95% of the studied lakes. The remaining minority are more dominantly sourced by snowmelt and/or permafrost thaw. Isotope‐based water balance estimates indicate 58% of lakes lose more than half of inflow by evaporation. For 26% of the lakes studied, evaporative losses exceeded supply. Surface area trend analysis indicates that most lakes were near their maximum extent in the early 1980s during a relatively cool and wet period. Subsequent reductions can be explained by moisture deficits and greater evaporation.
Fluid ascent during the 2004–2005 unrest at Mt. Spurr inferred from seismic tomography
Authors: Koulakov Ivan , West Michael , Izbekov Pavel
Published: June 2013

We present a seismic model of the crust beneath Mt. Spurr Volcano in Alaska based on tomographic inversion of local earthquake data recorded by temporary seismic network during the unrest of Mt. Spurr in 2004–2005. Beneath the northern vent of Mt. Spurr, where the most intensive fumarolic activity was observed during the last unrest, we observe a finger‐shaped anomaly with a higher P and lower S velocity, which corresponds to high Vp/Vs ratio. Another anomaly is located to the south of Crater Peak approximately beneath the same location where an explosive eruption occurred in 1992. We propose that these two finger anomalies represent separated conduits of magma and volatiles. The NE conduit extends to the surface and enables free volatile flux. The SE conduit seems to be blocked at a ca. 20 km depth and in case of continuous pressure build up may become a source of an explosive eruption.
SPILLOVERS OF HEALTH EDUCATION AT SCHOOL ON PARENTS' PHYSICAL ACTIVITY
Authors: Berniell Lucila , de la Mata Dolores , Valdés Nieves
Published: June 2013

This paper exploits state health education (HED) reforms as quasi‐natural experiments to estimate the causal impact of HED received by children on their parents' physical activity. We use data from the Panel Study of Income Dynamics for the period 1999–2005 merged with data on state HED reforms from the National Association of State Boards of Education Health Policy Database and the 2000 and 2006 School Health Policies and Programs Study. To identify the spillover effects of HED requirements on parents' behavior, we use several methodologies (triple differences, changes in changes, and difference in differences) in which we allow for different types of treatments. We find a positive effect of HED reforms at the elementary school on the probability of parents doing light physical activity. Introducing major changes in HED increases the probability of fathers engaging in physical activity by between 6.3 and 13.7 percentage points, whereas on average, this probability for mothers does not seem to be affected. We analyze several heterogeneous impacts of the HED reforms to unveil the mechanisms behind these spillovers. We find evidence consistent with hypotheses such as gender specialization of parents in childcare activities or information sharing between children and parents. Copyright © 2013 John Wiley & Sons, Ltd.
PER1 and CLOCK: Potential circulating biomarkers for head and neck squamous cell carcinoma
Authors: Hsu Cheng‐Ming , Lin Pai‐Mei , Lai Chi‐Chih , Lin Hsin‐Ching , Lin Sheng‐Fung , Yang Ming‐Yu
Published: June 2013

Background

Circadian clock regulates daily rhythms in various physiologic processes and deregulated circadian clock are linked to cancers. We have previously demonstrated the association between altered circadian clock genes (CCGs) and head and neck squamous cell carcinoma (HNSCC). The purpose of this study was to investigate whether the CCGs were also altered in peripheral blood (PB) of patients with HNSCC.

Methods

The 9 CCGs expression profiles of PB leukocytes from 94 patients with HNSCC and 56 healthy individuals were investigated using real‐time quantitative reverse transcriptase‐polymerase chain reaction (qRT‐PCR) and immunocytochemistry.

Results

All the 9 CCGs were significantly downregulated in the PB of preoperative patients (p < .0001). Recovery of PER1 and CLOCK expression was observed in postoperative patients with good prognosis but not in patients that died within 1 year after surgery.

Conclusion

CCGs were also altered in PB leukocytes of patients with HNSCC and PER1 and CLOCK are potential circulating prognostic markers for HNSCC. © 2013 Wiley Periodicals, Inc. Head Neck 36: 1018–1026, 2014
Resection margins and prognosis in locally invasive thyroid cancer
Authors: Hartl Dana M. , Zago Sophie , Leboulleux Sophie , Mirghani Haïtham , Déandreis Desirée , Baudin Eric , Schlumberger Martin
Published: June 2013

Background

Invasive thyroid cancer is rare, and the extent of surgery controversial. The purpose of this study was to present and evaluate therapeutic prognostic factors.

Methods

We conducted a retrospective single‐center study of differentiated thyroid carcinoma invading the larynx, trachea, and/or esophagus treated surgically with macroscopic complete resection.

Results

Forty‐six patients (average age, 57 years; average follow‐up, 4 years) were included. Free margins (R0) were obtained for 22 of 46 (49%) and microscopic residual tumor was present after surgery (R1) for 24 (51%). Ten‐year actuarial local control was 100% for R0 and 75% for R1 (p = .08). Five‐year local control was lower for recurrent tumors versus inaugurally invasive disease (63% vs 87%; log‐rank p = .011). Five‐year and 10‐year actuarial disease‐specific survival (DSS) was correlated with preoperative distant metastases (100% and 87%, respectively, for M0 vs 68% and 34% for M1; p = .01).

Conclusion

A trend toward lower local control was observed for R1 versus R0. The morbidity of surgery should be weighed against the prognosis if metastases are present. © 2013 Wiley Periodicals, Inc. Head Neck 36: 1034–1038, 2014
Cucurbitane‐Type Triterpenoids from Momordica charantia
Authors: Cheng Bao‐Hui , Chen Jian‐Chao , Liu Jie‐Qing , Zhou Lin , Qiu Ming‐Hua
Published: June 2013

The six new cucurbitane‐type triterpenoids 1–6, along with the ten known triterpenoids 7–16, were isolated from the vines and leaves of Momordica charantia. The structures of the new compounds were elucidated as (3β,7β,15β,23E)‐3,7,15,25‐tetrahydroxycucurbita‐5,23‐dien‐19‐al (1), (3β,7β)‐3,7,22,23‐tetrahydroxycucurbita‐5,24‐dien‐19‐al (2), (3β,7β)‐3,7,23,24‐tetrahydroxycucurbita‐5,25‐dien‐19‐al (3), (3β,7β,23S)‐3,7,23‐trihydroxycucurbita‐5,24‐dien‐19‐al 7‐β‐D‐glucopyranoside (4), (3β,7β,23E)‐cucurbita‐5,23‐diene‐3,7,19,25‐tetrol 7‐β‐D‐glucopyranoside (5), and (3β,7β,23E)‐3,7‐dihydroxy‐25‐methoxy‐cucurbita‐5,23‐dien‐19‐al 3‐β‐D‐allopyranoside (6), by extensive analyses of their spectral data, as well as by chemical methods.
New Secondary Metabolites from Allium victorialis
Authors: Khan Sadia , Fatima Itrat , Hussain Kazmi Mehdi , Malik Abdul
Published: June 2013

Allumines A and B (1 and 2, resp.), two new steroidal alkaloids, and a new cyclopentene derivative, 3, were isolated from the CHCl3‐soluble fraction of the whole plant of Allium victorialis. Their structures were elucidated by spectroscopic techniques, including 1D‐ and 2D‐NMR spectroscopy.
Fighting the Cybercrime Plague
Authors: Singleton Tommie
Published: June 2013

As anyone following the news can tell you, we're in the middle of a Cybercrime Crime Wave. Not only is there a lot more cybercrime, but the crimes are a lot more dangerous. And this plague is affecting everyone. Cybercrime is everywhere. It is affecting both public and private entities, and small firms as well as big companies. The author investigates just who is at risk, and some measures to take that will help protect those at risk. © 2013 Wiley Periodicals, Inc.
Your Guide to Authenticating Mobile Devices
Authors: Mooney J. Lowell , Parham Abbie Gail , Cairney Timothy D.
Published: June 2013

New information technology (IT) mobile devices—such as the iPhone and iPad—are increasingly emerging in the consumer market first. Then, they spread to the workplace. But this is creating major privacy and security headaches for corporate executives. Surveys show that IT groups significantly underestimate—by as much as 50%—how many employees use their own mobile devices for work purposes. So what is to be done? The authors take an in‐depth look at one vitally important security measure: user authentication. Companies need to go beyond just using passwords if they want to stay safe and secure. This article shows you how. It includes step‐by‐step instructions and a series of valuable checklists. © 2013 Wiley Periodicals, Inc.
Magnetic correlation functions in the slow and fast solar wind in the Eulerian reference frame
Authors: Weygand James M. , Matthaeus W. H. , Kivelson M. G. , Dasso S.
Published: June 2013

Simultaneous multiple point measurements of the magnetic field from seven spacecraft are employed to estimate the Eulerian correlation function and decorrelation time scales in the near Earth solar wind for two different solar wind speed ranges. We find that the Eulerian decorrelation time scale differs significantly in the slow solar wind (<450 km/s), where quasi‐two‐dimensional turbulence dominates, and in the fast solar (>600 km/s) wind, where slab‐type turbulence dominates. In slow solar wind, the decorrelation time is 215 ± 43 min, and in fast solar wind, the decorrelation time scale is 114 ± 23 min, which indicates that decorrelation times vary with the nature of the turbulence. The values reported here are comparable to estimates of decorrelation times based on a number of different models, but do not clearly support or refute any specific solar wind turbulence model. These results may be useful in magnetohydrodynamic modeling of the solar wind and can contribute to our understanding of solar and galactic cosmic ray diffusion in the heliosphere.
Cluster observations near reconnection X lines in Earth's magnetotail current sheet
Authors: Hwang K.‐J. , Goldstein M. L. , Wendel D. E. , Fazakerley A. N. , Gurgiolo C.
Published: June 2013

Magnetic reconnection is an efficient way to convert magnetic energy into particle energy. In this paper, we use Cluster thermal electron and ion measurements in the vicinity of a reconnection X line to delineate the structure of the reconnection current sheet. Multispacecraft observations made by Cluster on 18 August 2002 indicate that an X line drifted close to the spacecraft, about 3.4 RE earthward of the position where another X line had been observed earlier. Comparison of the Hall magnetic and electric field geometry and the observed properties of energetic electron beams streaming along the separatrix between the Cluster spacecraft indicates that the second X line formed within 20 s of the observation of the first X line. Repeated flow reversals and Hall field geometry together with the presence of a magnetic island embedded in the outflow region downstream of the first X line suggest that the initial current sheet was unstable, perhaps to the tearing mode. We identify a region with a thickness of 0.72 ion inertial lengths (29 electron inertial lengths, de) of super‐Alfvénic electron outflow (greater than the ion in‐flow Alfvén speed) during the period when the spacecraft was in the vicinity of the neutral sheet. Slightly below the neutral sheet, Cluster observed asymmetric counter‐streaming electrons with a loss of axisymmetry in the electron (V⟂1,V⟂2) distribution functions over a thin boundary with a thickness of several de. This electron‐scale transition layer was embedded in a much wider region where both the ion and electron Walén tests failed, and the electron super‐Alfvénic bulk outflow jets with high‐energy electron beams were detected. Those phenomena provide details of the substructure of the reconnection current sheet and suggest that the spacecraft traversed or skimmed the tailward edge of an elongated electron current layer. We also note that this event differs from a previously reported reconnection event in that strong electron temperature anisotropy (T∥>T⟂) is observed both in the inflow region and in the exhaust, where the anisotropy appears to be associated with the elongated electron outflow jets.
Evidence for strong middle Pleistocene earthquakes in the epicentral area of the 6 April 2009 L'Aquila seismic event from sediment paleofluidization and overconsolidation
Authors: Storti F. , Aldega L. , Balsamo F. , Corrado S. , Del Monaco F. , Di Paolo L. , Mastalerz M. , Monaco P. , Tallini M.
Published: June 2013

Obtaining constraints on maximum earthquake energy from fossil geological evidence has a primary importance for complementing historical information toward the proper mitigation of seismic hazard in a region. In this paper, we describe a newly discovered extensional fault zone in the western L'Aquila basin (Italy), associated with large paleofluidization structures. Paleofluidization‐bearing Calabrian sediments provide evidence for very shallow burial from mineralogical, organic matter thermal maturity, and flat dilatometer test data, whereas density of organic matter shows anomalously high values. We propose that all these pieces of information can be reconciled into a paleoseismological scenario where sediment liquefaction and fluidization in early middle Pleistocene times, as well as dewatering and overconsolidation, were coseismically triggered by strong earthquakes with magnitude approaching or slightly exceeding 7.0.
Statistical modelling of extreme precipitation indices for the Mediterranean area under future climate change
Authors: Hertig E. , Seubert S. , Paxian A. , Vogt G. , Paeth H. , Jacobeit J.
Published: June 2013

Projected changes of extreme precipitation in the Mediterranean area up until the end of the 21st century are analysed by means of statistical downscaling. Generalized linear models are used as downscaling technique to assess different percentile‐based indices of extreme precipitation on a fine‐scale spatial resolution. In the region under consideration extreme precipitation is related to anomalies of the large‐scale circulation as well as to convective conditions. To account for this, predictor selection encompasses variables describing the large‐scale circulation (geopotential heights of the 700 hPa and 500 hPa levels, u‐ and v‐wind components of the 850 hPa level) as well as thermo‐dynamic parameters (specific humidity of the 850 hPa and 700 hPa levels, Showalter‐Index, convective inhibition). In the scope of the statistical downscaling approach a specific statistical ensemble technique is applied in order to allow for non‐stationarities in the predictors–predictand relationships. Consequently, the statistical ensembles include a range of possible future evolutions of extreme precipitation. Two different emission scenarios (A1B and B1), multiple runs for each scenario, and output of two different general circulation models (ECHAM5 and HadCM3) are applied to assess extreme precipitation under enhanced greenhouse warming conditions. The results yield mainly decreases over many parts of the Mediterranean area in spring. In summer increases are assessed around the Tyrrhenian Sea, the Ionian Sea, and the Aegean Sea, whereas decreases are projected for most of the western and northern Mediterranean regions. In autumn reductions of heavy rainfall occur over many parts of the western and central areas. In winter distinct increases are widespread in the Mediterranean area. Beyond the assessments using all predictors it is shown in the present contribution that different predictor variables can lead to varying statistical downscaling results. It points to distinct impacts of the change of specific atmospheric conditions on local extreme precipitation.
Asymptotic analysis of non‐discrete radiating modes for open waveguide structures
Authors: Nordebo Sven , Cinar Gökhan , Gustafsson Stefan , Ioannidis Andreas , Nilsson Börje
Published: June 2013

This paper presents an asymptotic analysis of non‐discrete radiating modes with applications in waveguide theory. As a main application, the radiating modes of an open waveguide structure with circular geometry is considered. A generalized Jordan's lemma is used to justify that field components can be calculated as the sum of discrete and non‐discrete modes, that is, as the sum of residues of poles and an integral along the branch‐cut defined by the transversal wavenumber of the exterior domain. An asymptotic expression is derived for field components at large distance along the waveguide and supplemented with rigorous upper and lower error bounds. A numerical example regarding the axial symmetric 0th order transverse magnetic modes of a thin copper wire in water is included to demonstrate that there may be a non‐trivial balance between the contributions from discrete and non‐discrete modes. Copyright © 2013 John Wiley & Sons, Ltd.
On the R‐semiseparation of the Stokes bi‐stream operator in inverted prolate spheroidal geometry
Authors: Hadjinicolaou M. , Protopapas E.
Published: June 2013

An analytical method, for deriving the complete general solution of the fourth order partial differential equation E4ψ=0, in the inverted prolate spheroidal coordinates is presented. This equation governs the axisymmetric Stokes flow and is employed in many applications where particle‐fluid systems are encountered. The complete solution is obtained by employing the method of the R‐separation of variables and the notion of semiseparability. The general Stokes stream function ψ is represented as a sum of two different kinds of functions where the first one belongs to the 0‐eigenspace of the operator E′2, and it is given in R‐separable form with R equals to the Euclidean distance r, whereas the second one belongs to the generalized 0‐eigenspace of the Stokes operator E′2 and it is given in R‐semiseparable form, with R equals now to r3. This result reveals that the equation E′4ψ = 0, in the inverted prolate spheroidal system, allows R‐semiseparation. In order to illustrate the method, we derive explicitly a particular eigenfunction of the generalized 0‐eigenspace of E′2. Copyright © 2013 John Wiley & Sons, Ltd.
Treatment of Sugarcane Bagasse Lignin Employing Atmospheric Pressure Microplasma Jet in Argon
Authors: Amorim Jayr , Oliveira Carlos , Souza‐Corrêa Jorge A. , Ridenti Marco A.
Published: June 2013

An atmospheric argon rf microplasma jet was employed to treat lignin samples. The treatment time was carried out from 30 min to 4 h resulting in a strong degradation of the lignin structure. The most important degradation was observed in functional groups having asymmetric in‐phase ring stretching as well as in CC and CO stretching vibrations. Simple calculations may help us explain the OH bond breakings by electron collisions inside the microplasma. In the afterglow condition, it was not observed any change on the lignin spectra.
How do Patients, Politicians, Physiotherapists and Other Health Professionals View Physiotherapy Research in Switzerland? A Qualitative Study
Authors: Schoeb Veronika , Rau Barbara , Nast Irina , Schmid Stefan , Barbero Marco , Tal Amir , Kool Jan
Published: June 2013

Background

Since 2002, the professional education for Swiss physiotherapists has been upgraded to a tertiary educational level. With this change, the need for research related to professional practice has become more salient. The elaboration of research priorities is seen as a possible way to determine the profession's needs, to help coordinate research collaborations and to address expectations regarding physiotherapy. There is still limited evidence about stakeholders' views with regard to physiotherapy research. The objective of this study was to investigate key stakeholders' opinions about research in physiotherapy in Switzerland.

Methods

Focus groups with patients, health professionals, researchers and representatives of public health organizations were conducted, and semi‐structured interviews were conducted with politicians, health insurers and medical doctors from three linguistic regions in Switzerland. An interview guide was elaborated. Data were transcribed and analysed using inductive content analysis (Atlas‐ti 6®).

Results

Eighteen focus groups and 23 interviews/written commentaries included 134 participants with various research experiences and from different settings. Fourteen categories were defined reflecting three themes: identity, interdisciplinarity and visibility. Stakeholders had positive views about the profession and perceived physiotherapists' important role now and in the future. Yet, they also felt that physiotherapy was not sufficiently recognized in society and not visible enough. A stronger professional identity would be key to enhancing interdisciplinary work.

Conclusions

Results of this qualitative study provide insights into key aspects for moving the physiotherapy profession forward. Identity is at the heart of physiotherapy, not necessarily in terms of research priorities but in the definition of domains of competence and future positioning. Identity is also tightly connected to Interdisciplinarity as this might threaten the existence of the profession. Stakeholders outside the profession insist on the importance of visibility. The results of this study can help stakeholders reflect on the future of physiotherapy and elaborate research priorities. © 2013 The Authors. Physiotherapy Research International published by John Wiley & Sons Ltd.
Scanning probe microscopy investigation of the mechanisms limiting electronic transport in substrate‐supported graphene
Authors: Giannazzo F. , Fisichella G. , Nigro R. Lo , Fiorenza P. , Franco S. Di , Marino A. , Piluso N. , Rimini E. , Roccaforte F.
Published: June 2013

The scattering mechanisms limiting electronic transport in substrate‐supported graphene have been investigated by mapping the electron mean free path (l) in graphene on substrates with different dielectric permittivities, i.e. SiO2(κSiO2=3.9), 4H‐SiC (0001) (κSiC=9.7) and SrTiO3(001) (κSrTiO3=330). From the analysis of the local l versus gate bias curves, histograms and nanoscale maps of the densities of charged impurities (NCI) have been extracted. l was found to increase from (107±6) nm to (218±11) nm moving from SiO2 to SiC substrate, whereas a decrease to (179±5)nm was found for gra‐ phene on SrTiO3. Furthermore, a clear correlation between the minima in the l maps and the maxima in the NCI maps was obtained for graphene on SiO2 and SiC, whereas the two maps are uncorrelated in graphene on SrTiO3. These results indicate that charged impurity scattering is the main source of the lateral inhomogeneity of l on lower κ substrates, like SiO2 and SiC, whereas a different scattering mechanism (probably resonant scattering) must be invoked as the origin of the nanoscale variations of l in graphene on high‐κ substrates like SrTiO3. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cold‐pool formation in a narrow valley
Authors: Vosper S. B. , Hughes J. K. , Lock A. P. , Sheridan P. F. , Ross A. N. , Jemmett‐Smith B. , Brown A. R.
Published: June 2013

A numerical model simulation of the formation of a cold pool within a narrow valley during a clear calm night is presented. The results are compared with measurements made during the COLd air Pooling EXperiment (COLPEX). It is demonstrated that the model provides a realistic simulation of the observed cold pool. The cold pool begins to form approximately 1.5 hours before sunset, when the near‐surface air within the valley starts to cool more rapidly than the air on the surrounding hills. The model potential temperature budget is used to determine which physical processes are most important for the evolution of the cold pool. The results show that sheltering provided by the valley causes a turbulent heat ﬂux divergence over the lowest 5 m above the valley ﬂoor, which is large compared with the other terms in the budget. This causes relatively rapid cooling of the air adjacent to the ground. On the surrounding hills the turbulent heat ﬂux divergence is larger than in the valley, but the enhanced cooling this provides is approximately balanced by an almost equally large warming tendency from advection. The net eﬀect of these two terms is small compared with that in the valley and therefore the cooling rate is smaller. Above 5 m, the cooling in the valley is dominated by local transport of cold air away from the surface into the interior valley atmosphere.
Robust Multivariate Control Chart for Outlier Detection Using Hierarchical Cluster Tree in SW2
Authors: Fan Shu‐Kai S. , Huang Hui‐Kuo , Chang Yuan‐Jung
Published: June 2013

The goal of this paper is to develop a new multivariate control chart that can effectively detect potential outlier(s) in multi‐dimensional data while keeping the masking and swamping effects under control. The hierarchical clustering tree plays a central role in the proposed control chart, in an attempt to improve the Sullivan and Woodall's second method, known as the SW2 method. Historical multivariate datasets taken from the literature are used as the benchmarks to illustrate the performance of the proposed control charts in comparison to nine existing methods for outlier detection. The two criteria, the masking and swamping rates, are used as yardsticks for the evaluation purpose. An additional simulation study by means of Monte Carlo experiments further verifies that the proposed control chart that incorporates the hierarchical clustering tree performs much better in outlier detection and swamping prevention than the original SW2 and minimum volume ellipsoid methods. Copyright © 2012 John Wiley & Sons, Ltd.
A Copula Markov CUSUM Chart for Monitoring the Bivariate Auto‐correlated Binary Observations
Authors: Dokouhaki Pershang , Noorossana Rassoul
Published: June 2013

Although in the statistical process control (SPC) literature, there are considerable number of researches related to the multivariates variables control charting (focusing on the variable quality characteristics), fewer investigations could be found regarding the multivariate attributes control charts (relying on the attribute quality characteristics). More specifically considering the multivariate attributes control charting, it would be more interesting to monitor the auto‐correlated data, since the real‐world processes usually include the data based on an auto‐correlation structure. Ignoring the auto‐correlation structure in developing a multivariate control chart increases the type I and type II errors simultaneously and consequently reduces the performance of the chart. The most important difficulty with developing multivariate attributes control charts is the absence of the joint distribution for the quality characteristics. This deficiency can be dispelled through the use of the copula approach for developing the joint distribution.

In this paper, we use the Markov approach for modeling the auto‐correlated data. Then, the copula approach is used to make the joint distribution of two auto‐correlated binary data series. Finally, based on this joint distribution, we develop a cumulative sum (CUSUM) chart. Hence, the proposed chart is entitled the copula Markov CUSUM chart. The proposed control chart is compared with the most recent and effective existing one in the literature. Based on the average number of observations to signal (ANOS) measure, it is considered that the developed control chart performs better than the other one. In addition, a real case study related to two correlated diseases such as the Type 2 Diabetes Mellitus and the Obesity, in which each has an auto‐correlated structure, is investigated to verify the applicability of the control chart. Copyright © 2012 John Wiley & Sons, Ltd.
Control Charts For Monitoring The Weibull Shape Parameter Based On Type‐II Censored Sample
Authors: Guo Baocai , Wang Bing Xing
Published: June 2013

In this paper, a new statistic is proposed to monitor the Weibull shape parameter when the sample is type II censored. The one‐sided and two‐sided average run length‐unbiased control charts are derived based on the new monitoring statistic. The control limits of the proposed control charts depend on the sample size, the failure number and the false alarm rate. Using Monte Carlo simulation, the performance of the proposed control charts is studied and compared with the range‐based charts proposed by Pascual and Li (2012), which is equivalent to the proposed control charts when r = 2. The simulation results show that the proposed control charts perform better than the ones of Pascual and Li (2012). This paper also evaluates the effects of parameter estimation on the proposed control charts. Finally, an example is used to illustrate the proposed control charts. Copyright © 2012 John Wiley & Sons, Ltd.
Influence of the type of alkali metal cation on the interaction of soluble silicates with porous anodic alumina
Authors: Gaggiano R. , De Graeve I. , Verbeken K. , Kestens L. A. I. , Terryn H.
Published: June 2013

Aqueous sodium silicate solutions are commonly used in pretreatments of aluminium alloys as cleaners and corrosion inhibitors. Silicate films are a promising alternative for corrosion protection and are able to confer high hydrophilicity to the metal surface. An interaction mechanism of soluble sodium silicates with anodic alumina was proposed in previous publications, where the sodium cation acts as ‘bridging’ element between the silicate anions and the anodic oxide. In this work, this model of interaction is extended by considering the effect of different types of alkali cations. Porous anodized aluminum oxides were silicate treated by dipping in water‐based silicate solutions of different monovalent cations, namely lithium, sodium and potassium. The surface modifications occurring on the oxide layer during immersion in solution are studied as a function of the type of cation at ratio SiO2/M2O = 1 (M = Li, Na, K) at two different temperatures of the silicate solution (30 °C and 70 °C). The morphological changes occurring on the oxide surface during immersion are observed by field emission scanning electron microscopy, while the reactions happening at the anodic alumina surface are studied by monitoring the open circuit potential as a function of time. The attack of the oxide layer at low silicon‐to‐cation ratio is quantified by means of wavelength dispersive X‐ray fluorescence. Copyright © 2013 John Wiley & Sons, Ltd.
TiO2 Single Crystal with Four‐Truncated‐Bipyramid Morphology as an Efficient Photocatalyst for Hydrogen Production
Authors: Zhang Kai , Liu Qian , Wang Hui , Zhang Rubo , Wu Chunhui , Gong Jian Ru
Published: June 2013

Diverse titanium dioxide (TiO2) nanostructures have attracted much attention recently due to their potential application in photocatalytic and photovoltaic fields. Here, the synthesis of a TiO2 single crystal with a novel four‐truncated‐bipyramid morphology is reported for the first time, produced by a simple hydrothermal method. Both peroxo titanic acid precursor and hydrofluoric acid capping agent are essential for the formation of this unique morphology. Moreover, the as‐prepared TiO2 photocatalyst exhibits excellent hydrogen production activity from an ethanol–water solution, which is attributed to exposure of both high‐energy {001} oxidative and low‐energy {101} reductive facets in an optimal ratio. The current findings will contribute greatly to development of more novel photocatalysts with controllable microscopic structures for hydrogen production.
Annealing Behavior of Accumulative Roll Bonding Processed Aluminum Composites
Authors: Su Lihong , Lu Cheng , Tieu Kiet , Deng Guanyu
Published: June 2013

Accumulative roll bonding (ARB) is an effective method to produce ultrafine‐grained (UFG) sheet materials with high strength. In this work, the ARB process up to five cycles was performed to the starting materials AA1050 and AA6061 and produced three different laminates: AA1050/AA1050, AA6061/AA6061, and AA1050/AA6061. The grain size of AA1050 and AA6061, in all laminates, was reduced significantly after ARB deformation. Meanwhile, a remarkable enhancement in the hardness was achieved. The materials were annealed at different conditions and the microstructures and mechanical properties of the materials were investigated. Static annealing was carried out at temperatures of 100–400°C for 30 min in order to examine the thermal stability of the aluminum alloy. The grain size and hardness evolution of both the AA1050 and AA6061 alloys, in all the three laminates, showed a similar change with the annealing temperature. Annealing induced hardening was observed at 100°C for all the materials examined, and the microstructure of the alloys stayed almost the same as the as‐deformed alloys. The materials softening started after annealing at 150°C, and the hardness decreased rapidly between 150 and 300°C and then stayed stable. The change of the hardness values with the annealing time at low temperature was nearly negligible. The hardness and grain size values of the AA1050 and AA6061 in both the monotonic laminates and composite are similar.
Collaborating on Assessment of the Undergraduate Student Experience
Authors: Shivers Melissa S. , McMillan Sally J.
Published: June 2013

This chapter focuses on selected collaborative initiatives involving academic and student affairs at the University of Tennessee, Knoxville.
Measuring the Second‐Year Transformational Experience Program (STEP) at The Ohio State University
Authors: Kennedy‐Phillips Lance C. , Uhrig Kellie J.
Published: June 2013

This case study describes the role of assessment in a program for second‐year students at The Ohio State University.
Climate change regional review: Russia
Authors: Sharmina Maria , Anderson Kevin , Bows-Larkin Alice
Published: June 2013

With climate change, an increasingly important focus of scientific and policy discourse, the Russian government has aimed to position the country as one of the leaders of the global process for addressing climate change. This article reviews a breadth of literature to analyze the politico‐economic situation in Russia with regard to international climate change negotiations, related domestic policies, societal attitudes, and climatic change impacts on Russia's territory. The analysis demonstrates how Russia has a pivotal role in influencing the future direction of international climate change mitigation and adaptation. Not only is Russia predisposed geographically to the impacts of climate change, but also it is a major emitter of greenhouse gases and a global supplier of fossil fuels, and remains a major force in international politics. This unique confluence of circumstances leaves Russia with a challenging dilemma. It can choose to acquiesce to short‐term political and economic considerations, adopt weak mitigation measures, and face potentially significant impacts. Or it can apply its considerable attributes and powers to initiate an epoch of international action to secure a low‐carbon climate‐resilient future. Although the former will see Russia subsumed into the international malaise on climate change, the latter may both quench the nation's ‘thirst for greatness’ and fill the void of international leadership. WIREs Clim Change 2013, 4:373–396. doi: 10.1002/wcc.236

This article is categorized under:

Policy and Governance > National Climate Change Policy

Trans‐Disciplinary Perspectives > Regional Reviews

Trans‐Disciplinary Perspectives > National Reviews
A Bis(μ‐phenoxo)‐Bridged Dizinc Complex with Hydrolytic Activity
Authors: Mitra Mainak , Singh Reena , Pyrkosz‐Bulska Monika , Haukka Matti , Gumienna‐Kontecka Elzbieta , Nordlander Ebbe
Published: June 2013

The dinuclear complex [Zn2(papy)2]·2CH3OH [H2papy = N‐(2‐hydroxybenzyl)‐N‐(2‐picolyl)glycine] was synthesized and characterized. The crystal structure of the complex reveals that both ZnII ions are pentacoordinate with distorted pentagonal bipyramidal coordination arrangements. The phenoxyl groups of each ligand bridge the two metal atoms, whereas each carboxylate of the ligand is terminally bound to one ZnII ion. Potentiometric studies of the ZnII:H2papy system in a methanol/water mixture show the existence of a mononuclear species at lower pH; but at a pH above 5, a dimeric species starts to dominate and transforms further into a bis(μ‐phenoxo) bridged dizinc complex by deprotonation of phenolic hydrogen. A kinetic study of the hydrolysis of bis(2, 4‐dinitrophenyl)phosphate at different pH, catalyzed by complex 1, indicates a maximum rate at pH 9, where the bis(μ‐phenoxo)‐bridged dizinc species corresponding to 1 dominates in solution.
Characterization and statistical modeling of irregular porosity in carbon/carbon composites based on X‐ray microtomography data
Authors: Drach B. , Drach A. , Tsukrov I.
Published: June 2013

Statistical analysis procedure is proposed to characterize volume, shape and orientation distribution of pores in chemical vapor infiltrated carbon/carbon composites. The microstructure data is provided by X‐ray microtomography. To characterize orientation distribution of pores, probability distribution functions of pore volume, orientation angles and principal moments of inertia are constructed. Based on this information, a statistically significant range of pore geometry parameters is determined for evaluation of their contribution to the effective elastic properties of the material. Using the design of experiment approach, a subset of 53 pores is selected for the finite element simulations. The results are analyzed to construct a 3‐factor stochastic model of a pore contribution to the overall elastic response based on its geometric parameters. It is determined that the non‐dimensionalized surface to volume ratio factor plays an important role for pores in this type of material. A 4‐factor model incorporating this ratio is proposed. The model is validated by direct finite element simulations for a set of 150 randomly selected pores not included in the initial subset. The accuracy of the proposed approach is compared with the traditionally used approximation of pores by equivalent ellipsoids.
On the dual‐mixed formulation for an exterior Stokes problem
Authors: Gatica G.N. , Hsiao G.C. , Meddahi S. , Sayas F.‐J.
Published: June 2013

This paper is concerned with a dual‐mixed formulation for a three dimensional exterior Stokes problem via boundary integral equation methods. Here velocity, pressure and stress are the main unknowns. Following a similar analysis given recently for the Laplacian, we are able to extend the classical Johnson & Nédélec procedure to the present case, without assuming any restrictive smoothness requirement on the coupling boundary, but only Lipschitz‐continuity. More precisely, after using the incompressibility condition to eliminate the pressure, we consider the resulting velocity‐stress approach with a Neumann boundary condition on an annular bounded domain, and couple the underlying equations with only one boundary integral equation arising from the application of the normal trace to the Green representation formula in the exterior unbounded region. As a result, we obtain a saddle point operator equation, which is then analyzed by the well‐known Babuška‐Brezzi theory: in particular, the well‐posedness of the formulation will be established.
High‐order finite volume schemes based on defect corrections
Authors: Filimon A. , Dumbser M. , Munz C.‐D.
Published: June 2013

For the approximation of steady state solutions, we propose an iterated defect correction approach to achieve higher‐order accuracy. The procedure starts with the steady state solution of a low‐order scheme, in general a second order one. The higher‐order reconstruction step is applied a posteriori to estimate the local discretization error of the lower‐order finite volume scheme. The defect is then used to iteratively shift the basic lower‐order scheme to the desired higher‐order accuracy given by the polynomial reconstruction. Hence, instead of solving the high‐order discrete equations the low‐order basic scheme is solved several times. This avoids that the high‐order reconstruction with a large stencil has to be implemented into an existing basic solver and can be seen as a non‐intrusive approach to higher‐order accuracy.
On the measurement of surface tension and contact angle
Authors: Miersemann E.
Published: June 2013

We propose a new method which combines experiments with numerical calculations to determine the capillary constant and the capillary contact angle. We measure the ascent of the liquid at the interior and at the exterior of a circular transparent tube. In contrast to known methods we do not assume that the contact angle is known. Assuming the interior contact angle is equal to the exterior angle, we find the capillary constant of the given liquid from the fact that the surface tensions of the interior and the exterior surfaces are equal. Dipping a cylindrical wire with constant circular cross section into a liquid with known surface tension we can determine the contact angle between the given liquid and the material from which the wire is made.
An extended Discontinuous Galerkin and Spectral Difference Method with modal filtering
Authors: Meister A. , Ortleb S. , Sonar T. , Wirz M.
Published: June 2013

We give a short overview of an extended Discontinuous Galerkin and Spectral Difference Method using PKD polynomials on triangular grids. A corresponding exponential filter is used to avoid oscillations near discontinuous solutions and to give some stabilization for nonsmooth testcases.
Properties and simplifications of constitutive time‐discretized elastoplastic operators
Authors: Sysala S.
Published: June 2013

In the paper, a general constitutive elastoplastic model for associated plasticity is investigated. The model is based on the thermodynamical framework with internal variables and can include basic plastic criteria with a combination of kinematic hardening and non‐linear isotropic hardening. The corresponding initial value constitutive elastoplastic problem is discretized by the implicit Euler method. The discretized one‐time‐step constitutive problem defines the elastoplastic operator, which is formulated by a simple generalization of a projection onto a convex set. Properties of the so‐called generalized projection are used for deriving basic properties of the elastoplastic operator like potentiality, monotonicity, Lipschitz continuity and local semismoothness. Further, hardening variables are eliminated from the projective definition of the elastoplastic operators, which yields relations among the models with hardening variables and the perfect plasticity model. Also a simplification of the operator for plastic criteria in eigenvalue forms is introduced. The simplifications are useful for a numerical implementation and can be used for deriving other properties like strong semismoothness of the elastoplastic operators for the classical plastic criteria or strong monotonicity of the stress‐strain operator for some models with hardening. The derived properties can be important for convergence analyses of Newton‐like methods and other mathematical and numerical analyses.
A novel method for the solution of the forward displacement problem of spherical parallel manipulators
Authors: Rodriguez J. , Ruggiu M.
Published: June 2013

In this paper, a novel method that solves the Forward displacement problem (FDP) of several common spherical parallel manipulators (SPMs) is presented. The method uses the quaternion algebra to express the FDP as a system of equations and the Dixon determinant procedure to construct univariate polynomials whose roots can be found either numerically or analytically. A case study is solved for a specific SPM, which satisfies certain geometric conditions, having 3 ‐ R(E)R architecture, with R denoting a revolute joint, E a planar motion generator and underlines indicating the actuated joint. In this case, the solutions of the system are obtained analytically by a symbolic method exploiting symmetries.
N‐Phase decagonal quasicrystalline circular inclusions under thermomechanical loadings
Authors: Wang X. , Schiavone P.
Published: June 2013

In this work a simple and effective method is proposed to solve the problem corresponding to plane strain deformations of an N‐phase decagonal quasicrystalline circular inclusion‐matrix system in which the circular inclusion is bonded to the surrounding matrix through (N‐2) co‐axial interphase layers. We consider three kinds of thermomechanical loadings: (i) the matrix is subjected to a remote uniform stress field; (ii) the composite undergoes a uniform temperature change; (iii) the matrix is subjected to a uniform heat flux at infinity. We find that it is sufficient to manipulate three 8 × 8 real matrices, a 5 × 5 real matrix, and another 4 × 4 real matrix to arrive at the complete temperature and thermoelastic fields within the circular inclusion and the surrounding matrix, irrespective of the number of interphase layers existing within the composite system. Our results clearly indicate that the existence of the intermediate interphase layer(s) mean that the internal stresses within the circular inclusion are: (i) sextic functions of the two coordinates x1 and x2 under the loading of a remote uniform stress field; (ii) quadratic functions of the two coordinates under the loading of a uniform temperature change; (iii) cubic functions of the two coordinates under the loading of a remote uniform heat flux. The design of neutral and harmonic coated circular inclusions is also discussed as an application of the derived solution. Our analysis suggests that a coated inclusion can be made neutral only to a remote isotropic phonon stress field; whereas it can be made harmonic to any remote uniform phonon stress field.
DNA elastic nonlinearities as multiple smooth combinations of soft and hard linear springs
Authors: Xiao H.
Published: June 2013

DNA molecules perform biological functions via large elastic deformations and conformational changes in courses of their interactions with the cellular machinery. Adequate characterization of DNA elasticity is accordingly essential to an in‐depth understanding of DNA functions. Because of profound complexity, however, nonlinear features inherent in DNA elasticity remains to be uncovered in a direct, full sense and a unified, explicit characterization over the entire stretch range has been unavailable. Here it is suggested that DNA elastic nonlinearities may be understood by combining linear springs with high compliance and high rigidity. This finding uncovers the inherent geometrical feature in profound nonlinearities of DNA elasticity and leads to a unified, explicit force‐extension formula up to breaking. This formula reveals for the first time a complete set of characteristic constants for DNA elasticity and is shown to provide a unified characterization for both double‐ and single‐stranded DNA molecules. Results are presented in a straightforward, broad sense independent of any substructural details.