bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal and thermomechanical behavior of amino functionalized and metal decorated MWCNTs/PMMA nanocomposite films
Authors: Raza Ramsha , Ali Saqib , Ahmed Fiaz , Ullah Shafiq , Grant John T.
Published: December 2013

The homogeneous nanocomposites (NC) films of amino modified and metal decorated multiwall carbon nanotubes (MWCNTs) with polymethylmethacrylate (PMMA) were synthesized through in‐situ free radical polymerization. Silver metal nanohybrids (Ag/MWCNTs) were prepared by two strategies, that is, reduction of metal salt in presence of sodium dodecyl sulfate and in‐situ growth from AgNO3 aqueous solution. The amino functionalization by ball milling enhanced the dispersion of MWCNT in monomer and produced a new class of radiation resistant NC. These synthesized films were characterized by FTIR, TGA, TEM, EDX, TC, DMA, and optical microscopy to ascertain their structural morphologies, thermal stability, and mechanical strength. Microscopic studies reflect the homogeneous mixing of amino functionalized and metal decorated MWCNTs in polymer matrix contributing in the enhancement of thermal stability, thermo‐mechanical strength, glass transition temperatures, and thermal conductivity of NC even at 0.25 wt% addition of modified nanofiller. The thermal stability of NC film at 0.25 wt% loading was increased around ≂50°C and the raise of thermo‐mechanical properties was observed up to 85% at 100°C in the presence of adsorbed surfactant. Thermal and thermomechanical behavior of pre and post UV/O3 irradiated NC films has been compared with neat polymer. The results revealed that amino modified nanofiller embedded network in polymer matrix can effectively disperse the radiation and has a dramatic reinforcement effect on the nature of degradation of PMMA matrix. POLYM. COMPOS., 35:1807–1817, 2014. © 2013 Society of Plastics Engineers
Crystal transition behavior of odd–odd nylon 11,11 under annealing and stretching
Authors: Liu Shaobing , Fu Peng , Liu Minying , Li Zhaopeng , Lv Zhengya , Zhao Qingxiang
Published: December 2013

Nylon 11,11 is a new odd–odd polyamide with multiple crystalline structures. The wide‐angle X‐ray scattering indicated that the structure of quenched sample was not amorphous but a γ‐form crystal with a relatively low crystallinity. The α‐form and the γ‐form crystal of nylon 11, 11 could be obtained by annealing the quenched samples at high and low temperature, respectively. No crystal transition happened for the α‐form sample when annealed at any temperature before melting. However, the γ‐form would quickly transform into the α‐form when annealed above 145°C. Under the stretching conditions, the α‐form rapidly transformed into the γ‐form at low temperature, while the γ‐form changed into the α‐form only at high temperature. These results indicated that the stretching inducement was beneficial to produce the γ‐form, and the thermal inducement was favorable to forming the α‐form. POLYM. ENG. SCI., 54:2785–2790, 2014. © 2013 Society of Plastics Engineers
Protein degradation and phosphorylation after freeze thawing result in spermatozoon dysfunction
Authors: Yuan Jing
Published: December 2013

Cryopreservation is widely used in many assisted conception units. Semen cryopreservation is the only proven method that offers many couples the chance to have children. However, spermatozoa are exposed to physical and chemical stressors during freezing and thawing that result in adverse changes in membrane lipid composition, sperm motility, viability, and acrosome status. Wang et al. (Proteomics 2014, 14, 298–310) evaluate the protein content of freeze‐thawed sperm samples relative to that of fresh sperm samples from the same normozoospermic donors. Four proteins are verified via Western blot and immunofluorescent staining, which are putatively involved in spermatozoon dysfunction. These marked differences demonstrated by Wang et al. suggest that dysfunctional spermatozoon after cryopreservation may be due to protein degradation and protein phosphorylation.
Antagonism of human CC‐chemokine receptor 4 can be achieved through three distinct binding sites on the receptor
Authors: Slack Robert J. , Russell Linda J. , Barton Nick P. , Weston Cathryn , Nalesso Giovanna , Thompson Sally‐Anne , Allen Morven , Chen Yu Hua , Barnes Ashley , Hodgson Simon T. , Hall David A.
Published: December 2013

Chemokine receptor antagonists appear to access two distinct binding sites on different members of this receptor family. One class of CCR4 antagonists has been suggested to bind to a site accessible from the cytoplasm while a second class did not bind to this site. In this report, we demonstrate that antagonists representing a variety of structural classes bind to two distinct allosteric sites on CCR4. The effects of pairs of low‐molecular weight and/or chemokine CCR4 antagonists were evaluated on CCL17‐ and CCL22‐induced responses of human CCR4+ T cells. This provided an initial grouping of the antagonists into sets which appeared to bind to distinct binding sites. Binding studies were then performed with radioligands from each set to confirm these groupings. Some novel receptor theory was developed to allow the interpretation of the effects of the antagonist combinations. The theory indicates that, generally, the concentration‐ratio of a pair of competing allosteric modulators is maximally the sum of their individual effects while that of two modulators acting at different sites is likely to be greater than their sum. The low‐molecular weight antagonists could be grouped into two sets on the basis of the functional and binding experiments. The antagonistic chemokines formed a third set whose behaviour was consistent with that of simple competitive antagonists. These studies indicate that there are two allosteric regulatory sites on CCR4.
SMT: Sparse multivariate tree
Authors: Deng Houtao , Baydogan Mustafa Gokce , Runger George
Published: December 2013

A multivariate decision tree attempts to improve upon the single variable split in a traditional tree. With the increase in datasets with many features and a small number of labeled instances in a variety of domains (bioinformatics, text mining, etc.), a traditional tree‐based approach with a greedy variable selection at a node may omit important information. Therefore, the recursive partitioning idea of a simple decision tree combined with the intrinsic feature selection ofL1regularized logistic regression (LR) at each node is a natural choice for a multivariate tree model that is simple, but broadly applicable. This natural solution leads to the sparse multivariate tree (SMT) considered here. SMT can naturally handle non‐time‐series data and is extended to handle time‐series classification problems with the power of extracting interpretable temporal patterns (e.g., means, slopes, and deviations). BinaryL1regularized LR models are used here for binary classification problems. However, SMT may be extended to solve multiclass problems with multinomial LR models. The accuracy and computational efficiency of SMT is compared to a large number of competitors on time series and non‐time‐series data. © 2013 Wiley Periodicals, Inc. Statistical Analysis and Data Mining, 2013
Space‐efficient tracking of persistent items in a massive data stream
Authors: Lahiri Bibudh , Tirthapura Srikanta , Chandrashekar Jaideep
Published: December 2013

Motivated by scenarios in network anomaly detection, we consider the problem of detecting persistent items in a data stream, which are items that occur ‘regularly’ in the stream. In contrast with heavy hitters, persistent items do not necessarily contribute significantly to the volume of a stream, and may escape detection by traditional volume‐based anomaly detectors.

We first show that any online algorithm that tracks persistent items exactly must necessarily use a large workspace, and is infeasible to run on a traffic monitoring node. In light of this lower bound, we introduce an approximate formulation of the problem and present a small‐space algorithm to approximately track persistent items over a large data stream. We experimented with three different datasets to see how the accuracy and memory footprint of the algorithm varies with the skewness of the dataset. Our algorithms performed best for the two datasets out of three which had highest skewness of persistence and lowest mean persistence. To our knowledge, this is the first systematic study of the problem of detecting persistent items in a data stream, and our work can help detect anomalies that are temporal, rather than volume‐based. © 2013 Wiley Periodicals, Inc. Statistical Analysis and Data Mining, 2013
Psychological characteristics of religious delusions
Authors: Iyassu Robel , Jolley Suzanne , Bebbington Paul , Dunn Graham , Emsley Richard , Freeman Daniel , Fowler David , Hardy Amy , Waller Helen , Kuipers Elizabeth , Garety Philippa
Published: December 2013

Purpose

Religious delusions are common and are considered to be particularly difficult to treat. In this study we investigated what psychological processes may underlie the reported treatment resistance. In particular, we focused on the perceptual, cognitive, affective and behavioural mechanisms held to maintain delusions in cognitive models of psychosis, as these form the key treatment targets in cognitive behavioural therapy. We compared religious delusions to delusions with other content.

Methods

Comprehensive measures of symptoms and psychological processes were completed by 383 adult participants with delusions and a schizophrenia spectrum diagnosis, drawn from two large studies of cognitive behavioural therapy for psychosis.

Results

Binary logistic regression showed that religious delusions were associated with higher levels of grandiosity (OR 7.5; 95 % CI 3.9–14.1), passivity experiences, having internal evidence for their delusion (anomalous experiences or mood states), and being willing to consider alternatives to their delusion (95 % CI for ORs 1.1–8.6). Levels of negative symptoms were lower. No differences were found in delusional conviction, insight or attitudes towards treatment.

Conclusions

Levels of positive symptoms, particularly anomalous experiences and grandiosity, were high, and may contribute to symptom persistence. However, contrary to previous reports, we found no evidence that people with religious delusions would be less likely to engage in any form of help. Higher levels of flexibility may make them particularly amenable to cognitive behavioural approaches, but particular care should be taken to preserve self-esteem and valued aspects of beliefs and experiences.
Microvascular Infiltration has Limited Clinical Value for Treatment and Prognosis in Hepatocellular Carcinoma
Authors: Portolani Nazario , Baiocchi Gian Luca , Molfino Sarah , Benetti Anna , Gheza Federico , Giulini Stefano Maria
Published: December 2013

Background

Microvascular infiltration (MVI) is considered a necessary step in the metastatic evolution of hepatocellular carcinoma (HCC), but its prognostic value after liver resection (LR) is uncertain. We studied the clinical value of MVI compared to the Milan criteria in a consecutive series of patients submitted to radical LR.

Methods

A total of 441 patients were retrospectively evaluated. MVI and the Milan criteria were analyzed and compared as prognostic factors for overall and disease‐free survival (DFS).

Results

MVI was present in 189 patients (42.8 %). Grading, satellitosis, size of cancer, and alfa fetoprotein value were significantly related to MVI, which was present in 34.3 and 53.2 % of Milan+ and Milan− patients, respectively (p = 0.00001). Both MVI and the Milan criteria were associated with a lower overall and DFS, but only the Milan criteria were associated with the rate of early recurrence and the feasibility of a curative treatment of the recurrence. The application of MVI parameters to patients classified by the Milan criteria further selects the outcome in Milan+ patients (5‐year survival rate of 54.1 and 67.9 %, respectively, in the presence or absence of MVI) but not in Milan− patients.

Conclusions

MVI is related to survival after LR for HCC, but the clinical value of this information is limited. In Milan+ patients, the absence of MVI selects the cases with better prognosis. In the presence of a liver recurrence, the Milan criteria related to the primary HCC show a better prognostic accuracy and have clinical relevance in the decision‐making process.
Pancreaticoduodenectomy: Outcomes in a Low‐Volume, Specialised Hepato Pancreato Biliary Unit
Authors: Kanhere H. A. , Trochsler M. I. , Kanhere M. H. , Lord A. N. , Maddern G. J.
Published: December 2013

Background

This study was designed to evaluate the outcomes of pancreaticoduodenectomy (PD) at a low‐volume specialised Hepato Pancreato Biliary (HPB) unit. Volume outcome analyses show significantly better results for patients undergoing PD at high‐volume centres (Begg et al. JAMA 280:1747–1751, 1998; Finlayson et al. Arch Surg 138:721–725, 2003; Birkmeyer et al. N Engl J Med 346:1128–1137, 2002; Gouma et al. Ann Surg 232:786–795, 2000). Centralisation of PD seems to be the logical conclusion to be drawn from these results. In countries like Australia with a small and widely dispersed population, centralisation may not be always feasible. Alternative strategy would be to have similar systems in place to those in high‐volume centres to achieve similar results at low‐volume centres. Many Australian tertiary care centres perform low to medium volumes of PD (Chen et al. HPB 12:101–108, 2010; Kwok et al. ANZ J Surg 80:605–608, 2010; Barnett and Collier ANZ J Surg 76:563–568, 2006; Samra et al. Hepatobiliary Pancreat Dis Int 10:415–421, 2011). Most of these have a specialised HPB unit, accredited by the Australia and New Zealand Hepatic pancreatic and biliary association (ANZHPBA), as training units for post fellowship training in HPB surgery. It is imperative to perform outcome‐based analyses in these units to ensure safety and high quality of care.

Methods

Retrospective analysis of database for periampullary carcinoma (1998 till date) was performed in an ANZHPBA accredited HPB unit based at a tertiary care teaching hospital in South Australia. Because age older than 74 years is shown to be a predictive marker of increased morbidity and mortality after a PD, we analysed the outcomes in this subset of patients separately.

Results

Fifty‐three patients underwent PD in 14 years. Overall mortality was 3.8 %. The last in hospital mortality was in 1999. The morbidity rates and the oncologic outcomes were similar to those in high‐volume units.

Conclusions

PD can be safely performed in a low‐volume specialised unit at centres where the amenities and processes at high‐volume centres can be replicated.
Winter climate change in plant–soil systems: summary of recent findings and future perspectives
Authors: Makoto Kobayashi , Kajimoto Takuya , Koyama Lina , Kudo Gaku , Shibata Hideaki , Yanai Yosuke , Cornelissen J. H. C.
Published: December 2013

The winter climate is changing in many parts of the world, and it is predicted that winter climate change will modify the structure and function of plant–soil systems. An understanding of these changes and their consequences in terrestrial ecosystems requires knowledge of the linkage between above‐ and below‐ground components as well as the species interactions found in plant–soil systems, which have important implications for biogeochemical cycles. However, winter climate‐change studies have focused on only a part of the ecosystem or ecological process. We summarize here recent findings related to the effects of winter climate and its changes on soil nitrogen (N) dynamics, greenhouse gas (N2O) emissions from the soil, N use by individual plants, vegetation development, and interactions between vegetation and pollinators to generate an integrative understanding of the response of the plant–soil system to winter climate change. This review indicates that the net effects on plants, soil microbes, pollinators, and the associated biogeochemical cycles are balanced among several processes and are highly variable depending on the context, such as the target species/functional group, original winter condition of the habitat, and type of climate change. The consequences of winter climate change for species interactions among plants, associated animals, and biogeochemical cycles are largely unknown. For further research, a large‐scale comparative study to measure ecosystem‐level functions is important, especially in less‐cold ecosystems.
Conventional and Non‐conventional Edible Oils: An Indian Perspective
Authors: Choudhary Monika , Sangha Jasvinder Kaur , Grover Kiran
Published: December 2013

The Indian dietary pattern has undergone major changes over the past 40 years. Many of these changes involve modification in dietary intake of fats and oils. In developing countries like India, vegetable oils are replacing animal fats because of the cost and health concerns. A wide range of vegetable oils are available in the market but the choice of healthy cooking oil has been a controversial subject since ideas keep on changing as new evidence accumulates. One of the factors holding back the increased use of value‐added healthy oils in India is that most potential consumers are genuinely not aware of their health benefits. Edible oil consumption is primarily a community‐driven phenomenon in India. The purpose of this paper is to highlight the current scenario of edible oils in India, their composition, health benefits, food applications, stability issues and future aspects as buying the right oil for health has become of great importance.
Multi‐length‐Scale Elucidation of Kinetic and Symmetry Effects on the Behavior of Stearic and Oleic TAG. I. SOS and SSO
Authors: Baker Mark , Bouzidi Laziz , Garti Nissim , Narine Suresh S.
Published: December 2013

Positional isomerism in triacylglycerols (TAG), present in a molecular ensemble arising from genetic, environmental or processing‐induced changes, can result in significant differences in the macroscopic physico‐chemical functionality of crystallized networks of the ensemble. The differences in phase behavior induced by positional isomerism and levels of unsaturation of pure oleoyl‐distearoyl TAG (SOS, SSO) were detailed at different length scales. The effect of cooling rate on the polymorphism, thermal properties and microstructure were systematically investigated between 0.1 and 5 °C/min. The symmetrical SOS presented a complex polymorphism and microstructure, which varied predictively with cooling rate. The crystal phases and transitions observed for this TAG are similar to those of cocoa butter. In contrast, the cooling rate had limited effect on the phase behavior of the asymmetrical SSO. The differences between the crystallization of SSO and SOS induced by kinetics are related to the kinked oleic acid at the outer position in the SSO molecule and favorable end group structure for SOS. The fundamental understanding gained from such model systems can be used in many industrial formulations, particularly foods.
Creative Thoughts as Acts of Free Will: A Two-Stage Formal Integration
Authors: Simonton Dean Keith
Published: December 2013

This article integrates two topics usually considered disciplines apart, namely, creativity and free will. In particular, creative thoughts are conceived as acts of free will. This integration begins by reviewing recent advances in a specific two-stage theory of creative problem solving, namely blind variation and selective retention (BVSR). After discussing the parallel two-stage theory of free will (chance then choice), both two-stage theories are then integrated into a single formal representation entailing choice initial probabilities, final utilities, and prior knowledge values. These three parameters are used to define the creativity of any given solution and the “sightedness” of any generated thought or choice. Both creativity and free will vanish as sightedness increases, but their relation to blindness is more complex, yielding a triangular joint distribution that mandates a second-stage selection or decision process. In addition, to accommodate the need to create choices actively rather than just decide among given choices, the treatment expands to encompass both thoughts and choices as combinatorial products. This extension connects the discussion of free will with both combinatorial models of creativity and the research on the factors that enable a person to engage in free combinatorial processes. The article closes with suggestions of future empirical and theoretical research with respect to psychology, philosophy, and potential future exchanges between the two disciplines.
Equal Time for Psychological and Biological Contributions to Human Variation
Authors: Kagan Jerome
Published: December 2013

The recent increase in the number of studies designed to document the contributions of biological processes to human psychological variation has been accompanied by a decreased interest in discovering the particular experiences that are associated with class of rearing and identifications that contribute to the same outcomes. This editorial suggests 4 reasons for this state of affairs. They are the technological advances in biology; the favorable attitude toward materialistic explanations; the failure by earlier generations of social scientists to acknowledge the influences of temperamental biases and identifications with family, class, and ethnicity; and an emerging sentiment characterized by a reluctance to assign responsibility to victims for their states of distress.
Training Health Care Providers to Conduct Adherence Promotion in Pediatric Settings: An Example With Pediatric Asthma
Authors: Rohan Jennifer M. , Drotar Dennis , Perry Andrea R. , McDowell Karen , Malkin Julia , Kercsmar Carolyn
Published: December 2013

This study described the development, feasibility, and preliminary effectiveness of an adherence promotion intervention delivered by pediatric health care providers and facilitated by pediatric psychologists to children and adolescents ages 5–14 years with asthma and their caregivers ( N = 6). Individual time-series analyses indicated that the intervention was associated with enhanced adherence to daily inhaled corticosteroids. Moreover, the intervention (e.g., feedback to children and parents concerning treatment adherence based on electronic monitoring and problem solving concerning barriers to adherence promotion) was shown to be feasible for delivery in routine follow-up care for asthma and acceptable to families. Findings of this pilot study demonstrated the effectiveness of provider-based adherence promotion to promote adherence to treatment in pediatric asthma. Future research should replicate these findings with larger samples of children with asthma and focus on enhancing the sustainability of treatment adherence over time. Collaborative adherence promotion interventions developed by pediatric psychologists and pediatric subspecialists have the potential to advance clinical practice.
E-Health Interventions in Pediatrics
Authors: Rapoff Michael A.
Published: December 2013

The purpose of this article is to (a) define e-health interventions, modes of delivery, and comprehensiveness; (b) describe advantages of e-health interventions; (c) provide examples of e-health data collection and interventions; (d) review the research on e-health interventions; (e) describe barriers, and legal and ethical issues relevant to e-health interventions; and (f) provide recommendations for future research and clinical practice.
Brief Behavioral Intervention for Disruptive Behavior in a Child Following Frontal and Temporal Resection for Medically Intractable Epilepsy: A Case Report
Authors: Treble-Barna Amery , Chapman Stephanie G. , Schwartz David D. , Axelrad Marni E.
Published: December 2013

Children with epilepsy are at an increased risk for psychopathology, especially disruptive behavior disorders (DBD). Rates of DBD are especially high in children with frontal seizure foci who undergo frontal lobe surgery. Despite evidence that family and parenting factors have been shown to predict psychopathology in childhood epilepsy, there have been no studies of parenting interventions targeting disruptive behavior in these children. In the present case report, we adapted a validated parent management training intervention, the Brief Behavioral Intervention (BBI), to treat DBD in a 7-year-old boy who had undergone frontotemporal resection for medically intractable epilepsy. The family participated in 12 BBI sessions over a period of 19 weeks. Both parent and teacher report indicated reduction of significant disruptive behaviors to the normal range, with treatment gains generally maintained 2 months following treatment. The present case report demonstrates that parent management training in general, and BBI specifically, can be effective for treating problem behaviors in children with severe neurologically based behavioral presentations.
Emerging Issues: Psychology’s Place in the Primary Care Pediatric Medical Home
Authors: Tynan W. Douglas , Woods Kathryn E.
Published: December 2013

The passage of the Affordable Care Act has expanded the role of primary care providers in promoting child and adolescent socio-emotional health and well-being. With additional emphasis on prevention and expanded coverage for services such as developmental screenings, behavioral assessments, and obesity-related services, primary care practitioners will become increasingly involved in child mental health. This expansion provides additional opportunities for psychologists to be involved in service delivery in primary care settings. Many benefits have been noted for involving psychologists in primary care environments such as improved health outcomes and reduced costs. This commentary will explore implications of the Affordable Care Act for medical and psychology providers, along with how psychologists can become involved in implementing patient-centered medical homes, providing mental health services in primary care, with additional recommendations for policy and program changes to enhance integrated health care for children and adolescents.
Large eddy simulation of flow development and noise generation of free and swirling jets
Authors: Wan Zhen-Hua , Zhou Lin , Yang Hai-Hua , Sun De-Jun
Published: December 2013

Large eddy simulation is performed for investigating the local and far-field behaviors of free and swirling jets at moderate Reynolds number. By solving compressible boundary layer equations, the inflow profiles with different swirl number are calculated, and then their stability characteristics are analyzed based on linear stability theory. The amplification rates of swirling jets are higher than the free one, particularly for higher or negative azimuthal wavenumber modes. Multiple unstable modes are superimposed to construct inflow forcing. The quantities of flow and acoustic are presented and compared against the results of existed experiments and other computations, besides, the comparisons are also made among themselves. For swirling jets, the spreadings of jet half-width and vorticity thickness at the initial and transition stage are enhanced, but they are surpassed by the free jet at turbulent mixing stage. In all cases, the development of mixing layer initially is greatly influenced by frequencies f0 and f0/2 associated with upstream forcing. As the swirl intensity is increased, the growth rates of fluctuation quantities on the centerline and the nozzle lip line are raised, but the peak levels on the centerline are reduced substantially. In swirling jets, the strength of vortex pairing is decreased, and the pairing noise is weakened correspondingly. The overall sound pressure levels are lower than that of the free jet at all observation angles (ϕ), and about 3 decibels (dB) is reduced at ϕ ≃ 30° in the strong swirling case at a distance of 60 radii. The Fourier analyses of pressure and acoustic sources show that the modes are varied greatly, which suggests that the noise reduction should be corresponding to the change of instability waves.
Experimental validation of a newly designed 6 degrees of freedom scanning laser head: Application to three-dimensional beam structure
Authors: Di Maio D. , Copertaro E.
Published: December 2013

A new scanning laser head is designed to use single Laser Doppler Vibrometer (LDV) for performing measurements up to 6 degrees of freedom (DOF) at a target. The scanning head is supported by a rotating hollow shaft, which allows the laser beam to travel up to the scanning head from an opposite direction where an LDV is set up. The scanning head is made of a set of two mirrors, which deflects the laser beam with an angle so that the rotation of the scanning head produces a conical scan. When measurements are performed at the focal point of the conical scan then three translational vibration components can be measured, otherwise the very small circle scan, before and after the focal point, can measure up to 6 degrees of freedom, including three translations and three rotations. This paper presents the 6DOF scanning head and the measurements of 3D operational deflection shapes of a test structure.
Invited Article: Expanded and improved traceability of vibration measurements by laser interferometry
Authors: von Martens Hans-Jürgen
Published: December 2013

Traceability to the International System of Units has been established for vibration and shock measurements as specified in international document standards, recommendations, and regulations to ensure product quality, health, and safety. New and upgraded laser methods and techniques developed by national metrology institutes and by leading manufacturers in the past two decades have been swiftly specified as standard methods in the ISO 16063 series of international document standards. In ISO 16063-11:1999, three interferometric methods are specified for the primary calibration of vibration transducers (reference standard accelerometers) in a frequency range from 1 Hz to 10 kHz. In order to specify the same (modified) methods for the calibration of laser vibrometers (ISO 16063-41:2011), their applicability in an expanded frequency range was investigated. Steady-state sinusoidal vibrations were generated by piezoelectric actuators at specific frequencies up to 347 kHz (acceleration amplitudes up to 376 km/s2). The displacement amplitude, adjusted by the special interferometric method of coincidence to 158.2 nm (quarter the wavelength of the He-Ne laser light), was measured by the standardized interferometric methods of fringe counting and sine-approximation. The deviations between the measurement results of the three interferometric methods applied simultaneously were smaller than 1 %. The limits of measurement uncertainty specified in ISO 16063-11 between 1 Hz to 10 kHz were kept up to frequencies, which are orders of magnitude greater; the uncertainty limit 0.5 % specified at the reference frequency 160 Hz was not exceeded at 160 kHz. The reported results were considered during the development of ISO 16063-41 by specifying the instrumentation and procedures for performing calibrations of rectilinear laser vibrometers in the frequency range typically between 0.4 Hz and 50 kHz—the interferometric methods may be applied within expanded frequency ranges using refined techniques and procedures. It is concluded that calibration frequencies up to 0.5 MHz are attainable in compliance with the first international document standard for the calibration of laser vibrometers.
Dry granular avalanche down a flume: Choice of discrete element simulation parameters
Authors: Yang F.-L. , Chang W. T. , Huang Y. T. , Hsieh S. H. , Chen C. S.
Published: December 2013

This paper presents a method to assign soft-sphere contact model parameters in a discrete-element simulation with which we can reproduce the experimentally measured avalanche dynamics of finite dry granular mass down a flume. We adopt the simplest linear model in which interaction force is decomposed along or tangent to the contact normal. The model parameters are chosen uniquely to satisfy theoretical models or to meet experimental evidences at either the particle or the bulk size level. The normal mode parameters are chosen specifically to ensure Hertzian contact time (but not its force-displacement history) and the resulting loss of particle kinetic energy, characterized by a measured coefficient of restitution, for each pair of colliding surfaces. We follow the literature to assign the tangential spring constant according to an elasticity model but propose a method to assign the friction coefficient using a measured bulk property that characterizes the bulk discharge volume flow rate. The linear contact model with the assigned parameters are evaluated by comparing the simulated bulk avalanche dynamics down three slopes to the experimental data, including instantaneous particle trajectories and bulk unsteady velocity profile. Satisfying quantitative agreement can be obtained except at the free surface and the early-time front propagation velocity.
Two-photon spectroscopy of excitons with entangled photons
Authors: Schlawin Frank , Mukamel Shaul
Published: December 2013

The utility of quantum light as a spectroscopic tool is demonstrated for frequency-dispersed pump-probe, integrated pump-probe, and two-photon fluorescence signals which show Ramsey fringes. Simulations of the frequency-dispersed transmission of a broadband pulse of entangled photons interacting with a three-level model of matter reveal how the non-classical time-bandwidth properties of entangled photons can be used to disentangle congested spectra, and reveal otherwise unresolved features. Quantum light effects are most pronounced at weak intensities when entangled photon pairs are well separated, and are gradually diminished at higher intensities when different photon pairs overlap.
The effect of neutrally buoyant finite-size particles on channel flows in the laminar-turbulent transition regime
Authors: Loisel Vincent , Abbas Micheline , Masbernat Olivier , Climent Eric
Published: December 2013

The presence of finite-size particles in a channel flow close to the laminar-turbulent transition is simulated with the Force Coupling Method which allows two-way coupling with the flow dynamics. Spherical particles with channel height-to-particle diameter ratio of 16 are initially randomly seeded in a fluctuating flow above the critical Reynolds number corresponding to single phase flow relaminarization. When steady-state is reached, the particle volume fraction is homogeneously distributed in the channel cross-section (ϕ ≅ 5%) except in the near-wall region where it is larger due to inertia-driven migration. Turbulence statistics (intensity of velocity fluctuations, small-scale vortical structures, wall shear stress) calculated in the fully coupled two-phase flow simulations are compared to single-phase flow data in the transition regime. It is observed that particles increase the transverse r.m.s. flow velocity fluctuations and they break down the flow coherent structures into smaller, more numerous and sustained eddies, preventing the flow to relaminarize at the single-phase critical Reynolds number. When the Reynolds number is further decreased and the suspension flow becomes laminar, the wall friction coefficient recovers the evolution of the laminar single-phase law provided that the suspension viscosity is used in the Reynolds number definition. The residual velocity fluctuations in the suspension correspond to a regime of particulate shear-induced agitation.
Rigorous analysis of highly tunable cylindrical transverse magnetic mode re-entrant cavities
Authors: Le Floch J-M. , Fan Y. , Aubourg M. , Cros D. , Carvalho N. C. , Shan Q. , Bourhill J. , Ivanov E. N. , Humbert G. , Madrangeas V. , Tobar M. E.
Published: December 2013

Cylindrical re-entrant cavities are unique three-dimensional structures that resonate with their electric and magnetic fields in separate parts of the cavity. To further understand these devices, we undertake rigorous analysis of the properties of the resonance using “in-house” developed Finite Element Method (FEM) software capable of dealing with small gap structures of extreme aspect ratio. Comparisons between the FEM method and experiments are consistent and we illustrate where predictions using established lumped element models work well and where they are limited. With the aid of the modeling we design a highly tunable cavity that can be tuned from 2 GHz to 22 GHz just by inserting a post into a fixed dimensioned cylindrical cavity. We show this is possible, as the mode structure transforms from a re-entrant mode during the tuning process to a standard cylindrical transverse magnetic mode.
33
S hyperfine interactions in H2S and SO2 and revision of the sulfur nuclear magnetic shielding scale
Authors: Helgaker Trygve , Gauss Jürgen , Cazzoli Gabriele , Puzzarini Cristina
Published: December 2013

Using the Lamb-dip technique, the hyperfine structure in the rotational spectra of H233S and 33SO2 has been resolved and the corresponding parameters—that is, the sulfur quadrupole-coupling and spin–rotation tensors—were determined. The experimental parameters are in good agreement with results from high-level coupled-cluster calculations, provided that up to quadruple excitations are considered in the cluster operator, sufficiently large basis sets are used, and vibrational corrections are accounted for. The 33S spin-rotation tensor for H2S has been used to establish a new sulfur nuclear magnetic shielding scale, combining the paramagnetic part of the shielding as obtained from the spin–rotation tensor with a calculated value for the diamagnetic part as well as computed vibrational and temperature corrections. The value of 716(5) ppm obtained in this way for the sulfur shielding of H2S is in good agreement with results from high-accuracy quantum-chemical calculations but leads to a shielding scale that is about 28 ppm lower than the one suggested previously in the literature, based on the 33S spin-rotation constant of OCS.
Performance losses of drag-reducing spanwise forcing at moderate values of the Reynolds number
Authors: Gatti Davide , Quadrio Maurizio
Published: December 2013

A fundamental problem in the field of turbulent skin-friction drag reduction is to determine the performance of the available control techniques at high values of the Reynolds number Re. We consider active, predetermined strategies based on spanwise forcing (oscillating wall and streamwise-traveling waves applied to a plane channel flow), and explore via Direct Numerical Simulations (DNS) up to Reτ = 2100 the rate at which their performance deteriorates as Re is increased. To be able to carry out a comprehensive parameter study, we limit the computational cost of the simulations by adjusting the size of the computational domain in the homogeneous directions, compromising between faster computations and the increased need of time-averaging the fluctuating space-mean wall shear-stress. Our results, corroborated by a few full-scale DNS, suggest a scenario where drag reduction degrades with Re at a rate that varies according to the parameters of the wall forcing. In agreement with already available information, keeping them at their low-Re optimal value produces a relatively quick decrease of drag reduction. However, at higher Re the optimal parameters shift towards other regions of the parameter space, and these regions turn out to be much less sensitive to Re. Once this shift is accounted for, drag reduction decreases with Re at a markedly slower rate. If the slightly favorable trend of the energy required to create the forcing is considered, a chance emerges for positive net energy savings also at large values of the Reynolds number.
An experimental investigation of fingering instabilities and growth dynamics in inclined counter-current gas-liquid channel flow
Authors: Purvis J. A. , Mistry R. D. , Markides C. N. , Matar O. K.
Published: December 2013

The results of an experimental study involving low Reynolds number, counter-current flows of glycerol and air on an inclined glass substrate inside a rectangular channel are presented. The interface forms a thickened front immediately upstream of a thin, precursor layer region. This front is vulnerable to spanwise perturbations, which, under certain conditions, grow to acquire the shape of “fingers.” Decreasing the inclination angle has a stabilizing effect on the front; complete stability is achieved below a critical angle whose value depends on the remaining system parameters. Regions of transient finger formation are also observed. It is also found that increasing the ratio of the precursor to the inlet film thickness, and increasing the liquid and air flow-rates also exerts a stabilizing effect on the interface. Analyses of the initial finger growth-rate corroborate the findings of previous theoretical work, showing this growth-rate to be independent of inclination angle and liquid film Reynolds number, and weakly-dependent on the air flow-rate for low inclination angles. Both qualitative and quantitative agreement with theoretical studies from the literature was also found, in terms of the effects of flow parameters and the observed dynamics of the developing fingers.
Weakly nonlinear stability analysis of magnetohydrodynamic channel flow using an efficient numerical approach
Authors: Hagan Jonathan , Priede Jānis
Published: December 2013

We analyze weakly nonlinear stability of a flow of viscous conducting liquid driven by pressure gradient in the channel between two parallel walls subject to a transverse magnetic field. Using a non-standard numerical approach, we compute the linear growth rate correction and the first Landau coefficient, which in a sufficiently strong magnetic field vary with the Hartmann number as \documentclass[12pt]{minimal}\begin{document}$\mu _{1}\sim (0.814-\mathrm{i}19.8)\times 10^{-3}\textit {Ha}$\end{document}μ1∼(0.814−i19.8)×10−3Ha and \documentclass[12pt]{minimal}\begin{document}$\mu _{2}\sim (2.73-\mathrm{i}1.50)\times 10^{-5}\textit {Ha}^{-4}.$\end{document}μ2∼(2.73−i1.50)×10−5Ha−4. These coefficients describe a subcritical transverse velocity perturbation with the equilibrium amplitude \documentclass[12pt]{minimal}\begin{document}$|A|^{2}=\Re [\mu _{1}]/\Re [\mu _{2}](\textit {Re}_{c}-\textit {Re})\sim 29.8\textit {Ha}^{5}(\textit {Re}_{c}-\textit {Re}),$\end{document}|A|2=ℜ[μ1]/ℜ[μ2](Rec−Re)∼29.8Ha5(Rec−Re), which exists at Reynolds numbers below the linear stability threshold \documentclass[12pt]{minimal}\begin{document}$\textit {Re}_{c}\sim 4.83\times 10^{4}\textit {Ha}.$\end{document}Rec∼4.83×104Ha. We find that the flow remains subcritically unstable regardless of the magnetic field strength. Our method for computing Landau coefficients differs from the standard one by the application of the solvability condition to the discretized rather than continuous problem. This allows us to bypass both the solution of the adjoint problem and the subsequent evaluation of the integrals defining the inner products, which results in a significant simplification of the method.
Melting behavior of SnI4 reexamined
Authors: Fuchizaki Kazuhiro
Published: December 2013

The low-pressure crystalline phase of a molecular crystal, SnI4, has a rising melting curve that breaks abruptly at around 1.5 GPa, beyond which it becomes almost flat, with a slight maximum at about 3 GPa. Although the overall aspect of this melting curve can be captured by the Kumari–Dass–Kechin equation, the values for the parameters involved in the equation were definitely different from those predicted on the basis of the Clapeyron–Clausius relationship. On the other hand, the accuracy of our experimental data prevented us from judging whether the parameters are derivable from the Lindemann melting law, as shown independently by Kumari and Dass, and by Kechin. The Kraut–Kennedy and Magalinskii–Zubov relationships seem to be valid in the low-pressure region where the melting curve is rising. The breakdown of these relationships suggests a qualitative change in the intermolecular interaction upon compression, thereby making the melting behavior unusual.
Direct numerical simulation of turbulent heat transfer in a fluid-porous domain
Authors: Chandesris M. , D'Hueppe A. , Mathieu B. , Jamet D. , Goyeau B.
Published: December 2013

Turbulent heat transfer in a channel partially filled by a porous medium is investigated using a direct numerical simulation of an incompressible flow. The porous medium consists of a three-dimensional Cartesian grid of cubes, which has a relatively high permeability. The energy equation is not solved in the cubes. Three different heating configurations are studied. The simulation is performed for a bulk Reynolds number Reb = 5500 and a Prandtl number Pr = 0.1. The turbulent flow quantities are compared with the results of Breugem and Boersma [“Direct numerical simulations of turbulent flow over a permeable wall using a direct and a continuum approach,” Phys. Fluids 17, 025103 (2005)] to validate the numerical approach and macroscopic turbulent quantities are analyzed. Regarding the temperature fields, original results are obtained. The temperature fields show an enhanced turbulent heat transfer just above the porous region compared to the solid top wall, which can be related to the large vortical structures that develop in this region. Furthermore, these large structures induce pressure waves inside the porous domain which are responsible of large temperature fluctuations deep inside the porous region where the flow is laminar. Finally, macroscopic turbulent quantities are computed to get reference results for the development of macroscopic turbulent heat transfer models in fluid-porous domain.
Configurable silicon photonic crystal waveguides
Authors: Prorok Stefan , Petrov Alexander , Eich Manfred , Luo Jingdong , Jen Alex K.-Y.
Published: December 2013

In this Letter, we demonstrate that the mode cut off of a photonic crystal waveguide can be trimmed with high accuracy by electron beam bleaching of a chromophore doped polymer cladding. Using this method, configurable waveguides are realized, which allow for spatially resolved changes of the photonic crystal's effective lattice constant as small as 7.6 pm. We show three different examples how to take advantage of configurable photonic crystal waveguides: Shifting of the complete transmission spectrum, definition of cavities with high quality factor, and tuning of existing cavities.
First-principles energetics of water clusters and ice: A many-body analysis
Authors: Gillan M. J. , Alfè D. , Bartók A. P. , Csányi G.
Published: December 2013

Standard forms of density-functional theory (DFT) have good predictive power for many materials, but are not yet fully satisfactory for cluster, solid, and liquid forms of water. Recent work has stressed the importance of DFT errors in describing dispersion, but we note that errors in other parts of the energy may also contribute. We obtain information about the nature of DFT errors by using a many-body separation of the total energy into its 1-body, 2-body, and beyond-2-body components to analyze the deficiencies of the popular PBE and BLYP approximations for the energetics of water clusters and ice structures. The errors of these approximations are computed by using accurate benchmark energies from the coupled-cluster technique of molecular quantum chemistry and from quantum Monte Carlo calculations. The systems studied are isomers of the water hexamer cluster, the crystal structures Ih, II, XV, and VIII of ice, and two clusters extracted from ice VIII. For the binding energies of these systems, we use the machine-learning technique of Gaussian Approximation Potentials to correct successively for 1-body and 2-body errors of the DFT approximations. We find that even after correction for these errors, substantial beyond-2-body errors remain. The characteristics of the 2-body and beyond-2-body errors of PBE are completely different from those of BLYP, but the errors of both approximations disfavor the close approach of non-hydrogen-bonded monomers. We note the possible relevance of our findings to the understanding of liquid water.