A comparative performance study of common and popular task‐centric programming frameworks

Programmers today face a bewildering array of parallel programming models and tools, making it difficult to choose an appropriate one for each application. An increasingly popular programming model supporting structured parallel programming patterns in a portable and composable manner is the task‐centric programming model. In this study, we compare several popular task‐centric programming frameworks, including Cilk Plus, Threading Building Blocks, and various implementations of OpenMP 3.0. We have analyzed their performance on the Barcelona OpenMP Tasking Suite benchmark suite both on a 48‐core AMD Opteron 6172 server and a 64‐core TILEPro64 embedded many‐core processor. Our results show that the OpenMP offers the highest flexibility for programmers, and this flexibility comes to a cost. Frameworks supporting only a specific and more restrictive model, such as Cilk Plus and Threading Building Blocks, are generally more efficient both in terms of performance and energy consumption. However, Intel's implementation of OpenMP tasks performs the best and closest to the specialized run‐time systems. Copyright © 2013 John Wiley & Sons, Ltd.     

Aggregation behaviour of some β-cyclodextrin-based side-chain azo amphiphilic polyurethanes

New β-cyclodextrin-based side-chain azo amphiphilic polyurethanes were prepared. Aggregation behaviour was studied by employing steady-state fluorescence and UV–Vis spectroscopy techniques and, determination of the hydrodynamic diameter of micellar aggregates in N,N-dimethyl formamide and N,N-dimethyl formamide/ethanol mixture solutions was done. An apparent polarity evidenced by increasing I ₁/I ₃ ratio with the increasing concentration of polyurethanes except the polyurethanes with stronger intra- and intermolecular hydrogen bonding of hard segments was obtained. Pyrene resides predominantly in the interfacial region in micellar aggregates that is sensitive to polarity changes due to solvent penetration. Apparent critical micelle concentration due to the presence of β-cyclodextrin was determined by steady-state fluorescence and UV–Vis spectroscopy techniques which ranged between 10^?2 and 10^?1 g/L. Binding constants from both spectroscopy techniques were determined. The values of hydrodynamic diameter for the amphiphilic poly(ether urethane)s show that their aggregation behaviour is different in function of chemical composition, type and content of hard segment and hydrophobe/hydrophile ratio.     

Detection and Localization of Delaminations in Thin Carbon Fiber Reinforced Composites with the Ultrasonic Polar Scan

In this paper, the hybrid compliance-stiffness matrix method for simulating wave propagation in (delaminated) multilayered media with viscoelastic anisotropy has been confronted with high-quality amplitude and phase experiments on delaminated composites, obtained using the ultrasonic polar scan setup (UPS) in transmission by considering harmonic as well as pulsed ultrasound. Results are presented for multiple thin carbon/epoxy laminates with an artificial edge delamination induced by a foil insert, showing a good agreement between experimental recording and numerical modeling. The obtained results further reveal the feasibility of the harmonic UPS to detect and even locate the depth-position of multiple delaminations in fiber reinforced composites. Considering that the harmonic UPS method does not rely on the detection of different echoes like the classical C-scan, but rather expounds the conditions for efficient stimulation of guided waves in the solid, the method is found to be highly suited for inspecting thin composite materials for the presence of delaminations.     

Poly[N-(2-hydroxypropyl)methacrylamide]-based tissue-embedding medium compatible with MALDI mass spectrometry imaging experiments

Traditional tissue-sectioning techniques for histological samples utilize various embedding media to stabilize the tissue on a sectioning target and to provide a smooth cutting surface. Due to the ion suppression effect in MALDI ionization and number of background peaks in the low-mass region, these media are not suitable for mass spectrometry imaging (MSI) experiments. To overcome this, droplets of water are often used to mount the tissue on a sectioning target, but the ice block formed around the tissue does not provide a good support for sectioning of fragile samples. In this work, we propose a novel embedding media, compatible with MALDI ionization and MSI experiments, based on poly[N-(2-hydroxypropyl)methacrylamide] (pHPMA). Using a reversible addition-fragmentation chain transfer polymerization technique, well-defined pHPMA polymer with narrow mass distribution was prepared. Benefits of the resulted pHPMA-based embedding media were tested on different tissue samples.     

The effect of heat treatment temperature on the interfacial shear strength of C/C composites

This paper investigates the effect of heat treatment temperature on the interfacial shear strength (IFSS) of carbon/carbon composites reinforced with polyacrylonitrile-based fibers. A series of single fiber push-out tests were performed on specimens heat treated at 1800, 2100, and 2400 °C, using a nanoindenter with a flat ended conical tip. The microstructure was characterized using polarized light and transmission electron microscopy and the debonded fiber/matrix interface was examined using scanning electron microscopy. Wavelet analysis of the load–displacement data was used as an additional tool to investigate the initiation and progression of debonding. Compared to 1800 °C, heat treatment at 2400 °C was associated with a decrease in IFSS, from 12 to 7 MPa. Transmission electron microscopy study showed that the microstructure of the fiber/matrix interphase remained amorphous even with heat treatment at 2400 °C. The decrease in the IFSS can be partly attributed to the reorganization of the graphene sheets in the matrix in the vicinity of fiber/matrix interphase. The thermal expansion mismatch between fiber and pyrocarbon matrix is another possible reason for the observed decrease in the IFSS.     

The structure of maladaptive personality traits in childhood: A step toward an integrative developmental perspective for DSM-V.

The present study describes the construction of a taxonomy of trait-related symptoms in childhood, the Dimensional Personality Symptom Item Pool (DIPSI), and examines the replicability of the taxonomy's higher order structure across maternal ratings of referred (N = 205) and nonreferred (N = 242) children and self-ratings of adolescents (N = 453). The DIPSI's 4 higher order factors--that is, Emotional Instability, Disagreeableness, Introversion, and Compulsivity--showed clear correspondence with the dimensions of personality pathology found in adulthood (Dimensional Assessment of Personality Pathology-Basic Questionnaire; W. J. Livesley, 1990; Schedule for Nonadaptive and Adaptive Personality; L. A. Clark, 1993). These 4 factors can be further organized into 2 superfactors, representing Internalizing and Externalizing Traits, demonstrating empirical and conceptual relationships with psychopathology models in childhood and adulthood. The implications for the assessment and conceptualization of early trait pathology are discussed in the context of an integrative developmental perspective on the construction of the Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thermodynamic Properties of He@C60

Contributions to thermodynamic properties of the endohedral He@C₆₀, resulting from motion of He inside the cage, are calculated. The contribution to C_v shows a maximum at low temperatures. The maxima for ³He@C₆₀ and ⁴He@C₆₀ are at about 41 K and 30 K, respectively.     

Contribution of staling compounds to the aged flavour of lager beer by studying their flavour thresholds

The effect of 26 staling compounds on the aged flavour of a Belgian lager beer was studied. Strikingly, thresholds were regularly found to be substantially lower than those previously reported, and it appeared important to consider threshold values as indicative rather than absolute because of very large variations in sensitivity of individuals. In addition, a masking effect of isoamyl acetate and various interactions were observed between flavour compounds, which can considerably influence their flavour activity, even at sub-threshold concentrations. Cardboard flavour was essentially caused by (E)-2-nonenal. Additionally, methional, 3-methylbutanal, 2-furfuryl ethyl ether, β-damascenone and acetaldehyde were confirmed as key contributors to the aged flavour and to a lesser extent, (E,E)-2,4-decadienal, phenylacetaldehyde, 2-methylpropanal, diacetyl and 5-hydroxymethyfurfural. Finally, the addition of a selection of compounds could fairly well reproduce the flavour of aged lager beer, indicating that these compounds account for the major part of this flavour.     

On an on-line dynamic direct coordination method in process industry

A two-level production control system based on an on-line dynamic direct coordination method is discussed. Within the structure, each local unit makes decisions keeping to the coupling outputs as recommended by the coordinator. An application to a system in process industry is given.