bluuebunny/crossref_metadata_2025 huggingface dataset:
Hybrid nano ridge plasmonic polaritons waveguides
Authors: Mu Jianwei , Chen Lin , Li Xun , Huang Wei-Ping , Kimerling Lionel C. , Michel Jurgen
Published: September 2013

We demonstrate an ultra-subwavelength surface plasmonic polaritons waveguide, which can confine light in the nano-scale region with comparable low propagation loss. The mode can be squeezed to one thousandth of the diffraction spot size with micro-meter scale propagation distance and is highly sensitive to the buffer layer materials and geometric parameters. This design improves the performance of previous surface plasmonic polaritons waveguides and lends itself to complementary metal–oxide–semiconductor compatible fabrication. These waveguides can be used as a platform for active devices as well as for nano-sensing applications.
Interesting Magnetic and Optical Properties of ZnO Co-doped with Transition Metal and Carbon
Authors: Deng Si-hao , Xu Ming , Duan Man-yi , Brian Ong
Published: September 2013

Magnetic and optical properties of ZnO co-doped with transition metal and carbon have been investigated using density functional theory based on first-principles ultrasoft pseudopotential method. Upon co-doping with transition metal (TM) and carbon, the calculated results show a shift in the Fermi level and a remarkable change in the covalency of ZnO. Such cases energetically favor ferromagnetic semiconductor with high Curie temperature due to p-d exchange interaction between TM ions and holes induced by C doping. The total energy difference between the ferromagnetic and the antiferromagnetic configurations, spatial charge and spin density, which determine the magnetic ordering, were calculated in co-doped systems for further analysis of magnetic properties. It was also discovered that optical properties in the higher energy region remain relatively unchanged while those at the low energy region are changed after the co-doping. These changes of optical properties are qualitatively explained based on the calculated electronic structure. The validity of our calculation in comparison with other theoretical predictions will further motivate the experimental investigation of (TM, C) co-doped ZnO diluted magnetic semiconductors.
Urchin-like CoCu Bimetallic Nanocomposites for Catalytic Hydrogenolysis of Glycerol to Propanediols
Authors: Liu Qi-ying , Qiu Song-bai , Wang Tie-jun , Ma Long-long
Published: September 2013

Bimetallic CoCu nanocomposites were synthesized in polyol by using Ru as heterogeneous nucleation agent and stearic acid as surfactant, and their catalytic properties were investigated by hydrogenolysis of glycerol to propanediols. It was found that the surfactant could induce Co nanocrystals to form nanowires as structure-directing agent, while it's ineffective for Cu because only spherical Cu particles were produced under the same condition. When Co2+ and Cu2+ coexist in polyol, Cu2+ is firstly reduced and forms the spherical particles, and then the Cu particles afford surface for the subsequential reduction of Co2+ and growth of Co nanocrystals to form the nanorods, obtaining the urchin-like CoCu nanocomposites. The catalytic performance in selective hydrogenolysis of glycerol to propanediols proposed that the CoCu urchin-like nanocomposites was superior to the Co nanowires possibly due to that the synergistic effect between Co and Cu component promoted conversion of glycerol and obtained the higher propanediol yields based on the specific surface areas of the catalysts.
Ionization Energies and Dyson Orbials of Allyl Alcohol and Allyl Mercaptan Conformers
Authors: Yang Ju-bao , Wang Mei-ting , Wang Ke-dong , Liu Yu-fang
Published: September 2013

The conformers of allyl alcohol and allyl mercaptan were studied with B3LYP/aug-cc-pVTZ method. Their relative energies were calculated at MP3, MP4(SDQ), and CCSD(T) levels. The most stable conformers for these two molecules are Gauche-gauche′ (Gg′). The theoretical photoelectron spectra simulated with the calculated ionization energies demonstrate that there are at least four conformers in allyl alcohol and four conformers in allyl mercaptan in the gas-phase experiments. The Dyson orbitals of the highest occupied molecular orbital (HOMO) and the next HOMO (HOMO-1) of allyl mercaptan Gg′ conformer show strongly mixing ns and πc=c characteristics, which may be due to the resonance and inductive effects between πc=c and ns in HOMO-1 and HOMO.
Vibrational Spectra and Density Functional Theory Calculations of Metallotriphenylcorroles
Authors: Gao Hui-ling , Chen Fang , Wang Chun-lei , Wang Guo-bing , Chen Dong-ming
Published: September 2013

The infrared absorption and Raman scattering spectra were measured for the metallotriphenylcorroles (MTPCs, M=Cu, Co, Ni, Mn). The ground-state structures and vibrational spectra of MTPCs have been calculated with the density functional theory. The observed Raman and IR bands have been assigned based on the calculation results. Due to the symmetry lowering, the vibrational spectra of MTPCs are much more complex than metalloporphyrins, and several skeletal modes are found strongly coupled to the phenyl vibrations. The relationship between the Raman/IR frequencies and the structures of TPC ring is investigated. It is found that the vibrations involving the CαI stretch and CαCm stretch are sensitive to the size of corrole core. In particular, the frequency of v5, which is assigned to CαI stretch in coupling with the CαCm symmetric stretch, increases linearly with the decrease of the corrole core-sizes and may be used as a mark band to evaluate the structural change of the metallocorroles.
Preparation and Flame Retardancy of Polyurethane/POSS Nanocomposites
Authors: Xue Meng , Zhang Xian , Wu Zhao-feng , Wang Huan , Ding Xin , Tian Xing-you
Published: September 2013

Polyurethane/polyhedral oligomeric sisesquioxane (PU/POSS) nanocomposites were synthesized via polymerization utilizing the compatibility between POSS nanoparticles and 4,4′-diphenyl methylene diisocyanate. Scanning electron microscope images and Fourier transform infrared spectra revealed that POSS nanoparticles were dispersed in PU matrix. Thermal gravimetric analysis was employed to investigate the thermal decomposition behavior of PU/POSS nanocomposites at elevated temperatures. Then fire performance was evaluated by limiting oxygen index, underwriters laboratories 94 testing and char residue morphology. These results showed that the addition of POSS promoted the formation of char residues which were covered on the surface of polymer composites, leading to the improvement of thermal stability and flame retardancy.
Voltammetric characterisation of macroalgae-exuded organic ligands (L) in response to Cu and Zn: a source and stimuli for L
Authors: Murray Hollydawn , Meunier Guillaume , van den Berg Constant M. G. , Cave Rachel R. , Stengel Dagmar B.
Published: September 2013

Environmental context Identifying the source and stimuli responsible for organic ligands in seawater is crucial to understanding trace metal availability. Voltammetric techniques were employed to characterise the water chemistry of seaweed cultures exposed to low levels of Cu or Zn over 7 days. The results suggest that seaweeds are a potential source of metal complexing ligands and Cu and Zn appear to stimulate ligand production; further research is required to determine if this is applicable to macroalgae and metals outside this study. Abstract It is widely accepted that organic ligands control metal speciation in seawater, although little is known about their source, stimuli or identity. To gain insight on the possible environmental controls of metal complexing ligands (L), three brown macroalgae common in Irish waters (Ascophyllum nodosum, Fucus vesiculosus and Laminaria hyperborea) were cultured under low levels of Cu (0, 7.86 or 15.7nM) or Zn (0, 15.2 or 91.7nM) exposure. Seaweed chlorophyll-a fluorescence (Fv/Fm), metal speciation (Cu, Zn), complexing ligands (LM), conditional stability constants (logK′LM), glutathione (GSH), cysteine (Cys) and seaweed metal contents were monitored over 7 days. Although there was no effect on the internal seaweed metal concentrations, Cu and Zn additions significantly altered the water chemistry of each culture. Metal additions increased the total dissolved metal concentrations for all three species. Significantly higher [LM] values in cultures with added metals than the relevant controls point to both metals as stimuli of L production. All species released ligands in response to Cu or Zn exposure, indicating each seaweed is a relevant source of L. Comparison of logK′ values to those of previously determined ligands provides little evidence that the ligands reported here belong to the compounds identified as L in the literature.
Role of orthopyroxene in rheological weakening of the lithosphere via dynamic recrystallization
Authors: Farla Robert J. M. , Karato Shun-ichiro , Cai Zhengyu
Published: September 2013

Significance

The theory of plate tectonics is well established for Earth; however, why it operates is less well known. Here we propose that the deformation of a realistic two-phase aggregate (olivine and orthopyroxene) contributes to the rheological weakening and localization in the lower lithosphere and upper mantle. In particular, in a certain temperature range, the experimentally deformed aggregates show substantial weakening and the partitioning of strain in fine-grained regions composed of both olivine and orthopyroxene, possibly governed by grain-boundary pinning effects. However, at higher temperatures, the polyphase aggregates deform more homogeneously and are subject to less weakening. Using a model, we predict the conditions under which localized deformation may occur in the Earth.
Node-by-node disassembly of a mutualistic interaction web driven by species introductions
Authors: Rodriguez-Cabal Mariano A. , Barrios-Garcia M. Noelia , Amico Guillermo C. , Aizen Marcelo A. , Sanders Nathan J.
Published: September 2013

Significance

Examining the effects of species gains and losses is fundamental to understanding the assembly and disassembly of ecological communities in a changing world. However, field-based empirical studies that demonstrate the disassembly of mutualistic webs are exceedingly rare. In this study, we take advantage of an ongoing natural experiment that links the gain of invasive species (introduced large mammals and wasps), the loss of a native keystone species (a mistletoe), and the ensuing node-by-node disassembly of an interaction web in Patagonia, Argentina. Our results demonstrate that the gains and losses of species are both consequences and drivers of global change that can lead to underappreciated cascading coextinctions through the disruption of mutualisms.
Phonon-interface scattering in multilayer graphene on an amorphous support
Authors: Sadeghi Mir Mohammad , Jo Insun , Shi Li
Published: September 2013

Significance

The thermal conductivity of suspended graphene can be even higher than the basal-plane value of graphite, which is among the highest found in solids. However, when graphene is in contact with an amorphous material, the thermal conductivity is suppressed considerably. This paper reports that the thickness of multilayer graphene supported on an amorphous substrate needs to be more than 30 atomic layers to recover the graphite thermal conductivity. The finding is explained by long phonon mean free paths in graphite even along the cross-plane direction, and is used to clarify interface leakage of phonons as an important mechanism for the observed suppression. The result is relevant for the application of graphene for electronics, thermal management, and other applications.
Mechanism of E-cadherin dimerization probed by NMR relaxation dispersion
Authors: Li Ying , Altorelli Nicole L. , Bahna Fabiana , Honig Barry , Shapiro Lawrence , Palmer Arthur G.
Published: September 2013

Significance

Dimerization of transmembrane protein epithelial cadherin (E-cadherin) molecules extending from apposing cells is a critical event in calcium-dependent cell adhesion, a process essential for the formation and maintenance of tissues and organs. This study elucidates the molecular mechanism of E-cadherin dimerization by utilizing nuclear magnetic resonance spectroscopy to detect and characterize sparsely populated molecular species. In this mechanism, E-cadherin monomers first interact at an auxiliary interface to form a dimeric intermediate, which is followed by the conformational changes required to form the mature dimer. Besides contributing to the understanding of E-cadherin binding and recognition, the mechanism described in this work may illustrate a more general mechanism by which proteins with occluded binding sites interact with each other.
Adaptor complex AP2/PICALM, through interaction with LC3, targets Alzheimer's APP-CTF for terminal degradation via autophagy
Authors: Tian Yuan , Chang Jerry C. , Fan Emily Y. , Flajolet Marc , Greengard Paul
Published: September 2013

Significance

β-Amyloid aggregates are often found in the brains of Alzheimer’s patients. We have previously reported that β-amyloid levels can be down-regulated through activation of autophagy, a process involving the degradation of unnecessary or harmful proteins. However, the underlying mechanism of β-amyloid autophagy-mediated degradation is unknown. Here we demonstrate that the complex adaptor protein 2/phosphatidylinositol clathrin assembly lymphoid-myeloid leukemia (AP2/PICALM), via an interaction with a β-amyloid precursor, bridges β-amyloid degradation and autophagy. This work reveals mechanistic steps for the targeting of the β-amyloid precursor for degradation via autophagy and supports a genome-wide association study identifying PICALM as a risk factor for Alzheimer’s disease (AD). Altogether, these findings support the notion that activating autophagy is a valid approach for the AD field, which urgently needs novel therapeutic strategies.
Conversion from CUL4-based COP1–SPA E3 apparatus to UVR8–COP1–SPA complexes underlies a distinct biochemical function of COP1 under UV-B
Authors: Huang Xi , Ouyang Xinhao , Yang Panyu , Lau On Sun , Chen Liangbi , Wei Ning , Deng Xing Wang
Published: September 2013

Significance

CONSTITUTIVE PHOTOMORPHOGENESIS 1 (COP1) is a well-conserved multifunctional protein in both plants and animals. Depending on the context, COP1 can have distinct roles, such as an oncogene or a tumor suppressor in mammalian cells. In light regulation of plant development, COP1 is a central repressor under far-red and visible light whereas it is a positive regulator under UV-B. However, how COP1 positively regulates UV-B signaling remains largely unknown. In this study, we demonstrate that the UV-B–induced reorganization of COP1 complexes achieves a functional switch of COP1 from repressing to promoting photomorphogenesis.
Maximal rank for schemes of small multiplicity by Évain’s differential Horace method
Authors: Roé Joaquim
Published: September 2013

The Hilbert function of the union of

n
n

general

e
e

-fold points in the plane is maximal if

n
≥
4

e
2

n\ge 4e^2

or

n
n

is a square. The Hilbert function of a union of

A
A

,

D
D

,

E
E

singularity schemes in general position is maximal in every degree

>
28

>28

. The proofs use a computation of limits of families of linear systems whose special members acquire base divisors, an interesting problem in itself.
Characterization of almost 𝐿^{𝑝}-eigenfunctions of the Laplace-Beltrami operator
Authors: Kumar Pratyoosh , Ray Swagato , Sarkar Rudra
Published: September 2013

In 1980, Roe proved that if a doubly-infinite sequence

{

f
k

}

\{f_k\}

of functions on

R

\mathbb {R}

satisfies

f

k
+
1

=
(
d

f

k

/

d
x
)

f_{k+1}=(df_{k}/dx)

and

|

f

k

(
x
)

|

≤
M

|f_{k}(x)|\leq M

for all

k
=
0
,
±
1
,
±
2
,
⋯

k=0,\pm 1,\pm 2,\cdots

and

x
∈

R

x\in \mathbb {R}

, then

f
0

(
x
)
=
a
sin
⁡
(
x
+
φ
)

f_0(x)=a\sin (x+\varphi )

, where

a
a

and

φ
\varphi

are real constants. This result was extended to

R

n

\mathbb {R}^n

by Strichartz in 1993, where

d

/

d
x

d/dx

was substituted by the Laplacian on

R

n

\mathbb {R}^n

. While it is plausible that this theorem extends to other Riemannian manifolds or Lie groups, Strichartz showed that the result holds true for Heisenberg groups, but fails for hyperbolic

3
3

-space. This negative result can indeed be extended to any Riemannian symmetric space of noncompact type. We observe that this failure is rooted in the

p
p

-dependence of the

L
p

L^p

-spectrum of the Laplacian on the hyperbolic spaces. Taking this into account we shall prove that for all rank one Riemannian symmetric spaces of noncompact type, and more generally for the harmonic

N
A

NA

groups, the theorem actually holds true when uniform boundedness is replaced by uniform “almost

L
p

L^p

boundedness”. In addition we shall see that for the symmetric spaces this theorem can be used to characterize the Poisson transforms of

L
p

L^p

functions on the boundary, which somewhat resembles the original theorem of Roe on

R

\mathbb {R}

.
Knot points of typical continuous functions
Authors: Preiss David , Saito Shingo
Published: September 2013

It is well known that most continuous functions are nowhere differentiable. Furthermore, in terms of Dini derivatives, most continuous functions are nondifferentiable in the strongest possible sense except in a small set of points. In this paper, we completely characterise families

S

\mathcal {S}

of sets of points for which most continuous functions have the property that such small set of points belongs to

S

\mathcal {S}

. The proof uses a topological zero-one law and the Banach-Mazur game.
Smyd1b is required for skeletal and cardiac muscle function in zebrafish
Authors: Li Huiqing , Zhong Yongwang , Wang Zengfeng , Gao Jie , Xu Jin , Chu Wuying , Zhang Jianshe , Fang Shenyun , Du Shao Jun
Published: September 2013

Smyd1b is a member of the Smyd family that is specifically expressed in skeletal and cardiac muscles. Smyd1b plays a key role in thick filament assembly during myofibrillogenesis in skeletal muscles of zebrafish embryos. To better characterize Smyd1b function and its mechanism of action in myofibrillogenesis, we analyzed the effects of smyd1b knockdown on myofibrillogenesis in skeletal and cardiac muscles of zebrafish embryos. The results show that knockdown of smyd1b causes significant disruption of myofibril organization in both skeletal and cardiac muscles of zebrafish embryos. Microarray and quantitative reverse transcription-PCR analyses show that knockdown of smyd1b up-regulates heat shock protein 90 (hsp90) and unc45b gene expression. Biochemical analysis reveals that Smyd1b can be coimmunoprecipitated with heat shock protein 90 α-1 and Unc45b, two myosin chaperones expressed in muscle cells. Consistent with its potential function in myosin folding and assembly, knockdown of smyd1b significantly reduces myosin protein accumulation without affecting mRNA expression. This likely results from increased myosin degradation involving unc45b overexpression. Together these data support the idea that Smyd1b may work together with myosin chaperones to control myosin folding, degradation, and assembly into sarcomeres during myofibrillogenesis.
Far-infrared spectroscopy of a lensed starburst: a blind redshift from Herschel
Authors: George R. D. , Ivison R. J. , Hopwood R. , Riechers D. A. , Bussmann R. S. , Cox P. , Dye S. , Krips M. , Negrello M. , Neri R. , Serjeant S. , Valtchanov I. , Baes M. , Bourne N. , Clements D. L. , De Zotti G. , Dunne L. , Eales S. A. , Ibar E. , Maddox S. , Smith M. W. L. , Valiante E. , van der Werf P.
Published: September 2013

We report the redshift of HATLAS J132427.0+284452 (hereafter HATLAS J132427), a gravitationally lensed starburst galaxy, the first determined ‘blind’ by the Herschel Space Observatory. This is achieved via the detection of [C ii] consistent with z = 1.68 in a far-infrared spectrum taken with the SPIRE Fourier Transform Spectrometer (FTS). We demonstrate that the [C ii] redshift is secure via detections of CO J = 2 → 1 and 3 → 2 using the Combined Array for Research in Millimeter-wave Astronomy and the Institut de Radioastronomie Millimétrique's Plateau de Bure Interferometer. The intrinsic properties appear typical of high-redshift starbursts despite the high lensing-amplified fluxes, proving the ability of the FTS to probe this population with the aid of lensing. The blind detection of [C ii] demonstrates the potential of the SPICA Far-infrared Instrument imaging spectrometer, proposed for the much more sensitive Space Infrared Telescope for Cosmology and Astrophysics mission, to determine redshifts of multiple dusty galaxies simultaneously without the benefit of lensing.
How Does Multilevel Regression and Poststratification Perform with Conventional National Surveys?
Authors: Buttice Matthew K. , Highton Benjamin
Published: September 2013

Multilevel regression and poststratification (MRP) is a method to estimate public opinion across geographic units from individual-level survey data. If it works with samples the size of typical national surveys, then MRP offers the possibility of analyzing many political phenomena previously believed to be outside the bounds of systematic empirical inquiry. Initial investigations of its performance with conventional national samples produce generally optimistic assessments. This article examines a larger number of cases and a greater range of opinions than in previous studies and finds substantial variation in MRP performance. Through empirical and Monte Carlo analyses, we develop an explanation for this variation. The findings suggest that the conditions necessary for MRP to perform well will not always be met. Thus, we draw a less optimistic conclusion than previous studies do regarding the use of MRP with samples of the size found in typical national surveys.
Large-scale hypomethylated blocks associated with Epstein-Barr virus–induced B-cell immortalization
Authors: Hansen Kasper D. , Sabunciyan Sarven , Langmead Ben , Nagy Noemi , Curley Rebecca , Klein Georg , Klein Eva , Salamon Daniel , Feinberg Andrew P.
Published: September 2013

Altered DNA methylation occurs ubiquitously in human cancer from the earliest measurable stages. A cogent approach to understanding the mechanism and timing of altered DNA methylation is to analyze it in the context of carcinogenesis by a defined agent. Epstein-Barr virus (EBV) is a human oncogenic herpesvirus associated with lymphoma and nasopharyngeal carcinoma, but also used commonly in the laboratory to immortalize human B-cells in culture. Here we have performed whole-genome bisulfite sequencing of normal B-cells, activated B-cells, and EBV-immortalized B-cells from the same three individuals, in order to identify the impact of transformation on the methylome. Surprisingly, large-scale hypomethylated blocks comprising two-thirds of the genome were induced by EBV immortalization but not by B-cell activation per se. These regions largely corresponded to hypomethylated blocks that we have observed in human cancer, and they were associated with gene-expression hypervariability, similar to human cancer, and consistent with a model of epigenomic change promoting tumor cell heterogeneity. We also describe small-scale changes in DNA methylation near CpG islands. These results suggest that methylation disruption is an early and critical step in malignant transformation.
Homometry in the light of coherent beams
Authors: Ravy Sylvain
Published: September 2013

Two systems are homometric if they are indistinguishable by diffraction. A distinction is first made between Bragg and diffuse scattering homometry, and it is shown that in the last case coherent diffraction can allow the diffraction diagrams to be differentiated. The study of the Rudin–Shapiro sequence, homometric to random sequences, allows one to manipulate independently two-point and four-point correlation functions, and to show their effect on the statistics of speckle patterns. This study provides evidence that long-range order in high-order correlation functions has a measurable effect on the speckle statistics.
Method of spiral bevel gear tooth contact analysis performed in CAD environment
Authors: Sobolewski Bartłomiej , Marciniec Adam
Published: September 2013

Purpose

– The purpose of this paper is to present the use of a CAD system for the analysis of meshing of spiral bevel gears.

Design/methodology/approach

– The TCA computer programs are based on a purely mathematical model and require to get the numerical solution of a set of nonlinear equations. There are situations that the programs fail to obtain the proper solution. In such cases, geometrical gear models defined in CAD environment prove to be a good choice. This paper describes a tool for analyzing tooth contact and transmission errors of spiral bevel gear sets with tooth flanks represented as CAD free-form surfaces.

Findings

– A new method has been proposed to keep those surfaces in continuous contact in the whole range of meshing of a mating tooth pair. During meshing, the points of contact as well as the corresponding angles of rotation of both the pinion and the ring gear are recorded. Thus, the tooth contact path as well as the motion transmission error graph is determined. Then, the contact pattern that is formed by a set of instantaneous contact ellipses is designated.

Practical implications

– The TCA results are essential for the assessment of the gear set quality in the early stages of the process of its development.

Originality/value

– All the results presented in graphical form are very illustrative and easy to interpret.
Benefiting from your buddy
Authors: K. Dutta Dev
Published: September 2013

Purpose

– The purpose of this paper is to offer a conceptual understanding of the role played by social capital when firms engage in collaborative partnerships to develop their innovative capability, especially under environmental turbulence.

Design/methodology/approach

– The paper is theoretical in nature, drawing conceptual insights from two complementary theories: the resource-based view of the firm and institutional theory.

Findings

– Social capital plays a beneficial role by enhancing the innovative capability of firms, but only up to a point. The paper argues social capital has both positive and negative effects and follows a non-linear relationship with innovative capability. Further, this relationship is also affected by the level of environmental turbulence faced by the firm.

Originality/value

– By conceptualizing social capital as a double-edged sword in terms of its impact on firm innovative capability, the paper offers insights for managerial action and practice.
Commercialization of innovations: an overarching framework and research agenda
Authors: Datta Avimanyu , Reed Richard , Jessup Len
Published: September 2013

Purpose

– The commercialization of innovation, which is key to entrepreneurial success, is a combination of several entrepreneurial activities. Building on research from fields of management, strategy, entrepreneurship, economics, and marketing, the paper summarized the extant literature to develop a framework of commercialization and an agenda for future research. The paper aims to discuss these issues.

Design/methodology/approach

– Extensive review of literature, which was comprised of 194 articles across 62 journals in the fields of management, strategy, entrepreneurship, economics, and marketing.

Findings

– The literature was categorized into six broad themes of entrepreneurial activities: sources of innovations, types of innovation, market entry (capabilities and feasibility), protection, development, and deployment. Most of the research papers that were reviewed were concentrated on single theme.

Practical implications

– Given the identification of six key themes of entrepreneurial activity leading to the commercialization of innovations, research questions were posed as a means to move the research forward by integrating the themes.

Originality/value

– This is the first paper in its kind to integrate 194 papers from 62 journals to provide a comprehensive framework of commercialization of innovations.
The role of relational social capital in examining exporter-intermediary relationships
Authors: Carlos M.R. Pinho José
Published: September 2013

Purpose

– This paper aims to rely on a conceptual model that builds on, and synthesizes, the theoretical foundations of social capital (relational and cognitive) and cooperation. It assumes that the network of relationships and the set of resources embedded within it strongly influence the extent to which exporter-intermediary cooperation occurs.

Design/methodology/approach

– Following a quantitative methodological approach, a survey was applied to a sample of exporters to empirically test the proposed model.

Findings

– The findings reveal that among the six relationships, five are positively supported. Specifically, this study finds a positive and a significant impact of the two dimensions of social capital: cognitive (shared values) and relational (trust) on both commitment and cooperation. However, it did not support the impact of cognitive social capital on relational social capital.

Research limitations/implications

– One possible shortfall of this research relates to the characteristics of different cultural environments that small and medium sized enterprises (SMEs) face which may have influenced the results.

Practical implications

– Empirical findings are relevant as they may assist SME managers to invest in business relationships which enable the firms to achieve important competitive advantages.

Originality/value

– This article presents the original approach of looking at the link between relational social capital and export-intermediary relationships, which challenges the way this topic is generally examined.
An analysis of safety advisor roles and site safety performance
Authors: Cameron Iain , Hare Billy , Duff Roy
Published: September 2013

Purpose

– Present findings from a UK study, funded by the Institution of Occupational Safety and Health (IOSH), on the relationship between safety advisor roles and safety performance.

Design/methodology/approach

– Roles and organisational factors for contractors’ safety advisors (independent variables) were derived from existing literature. The dependent variable was “safety performance”, measured by accident incidence rate (AIR). Data were provided by 101 contractors and variance of means analysis was conducted.

Findings

– Contractors using only external safety consultants had an average AIR approximately three times those with internal safety staff. However, simply increasing internal safety personnel did not lead to increased safety performance. Contractors, where at least one safety advisor had authority to give orders had a lower mean AIR than those who did not. Other significant variables were: delivering safety training to employees; vetting sub-contractors; and the inclusion of an environmental management role.

Practical implications

– Employing at least one full-time internal safety person is better than relying solely on a safety consultant. If these safety advisers report to senior management then they have a greater chance of influencing others to act safely or commit resources to manage safety. Delivery of training, vetting sub-contractors and including environmental duties should feature in safety advisor roles.

Originality/value

– The assumption that merely increasing safety personnel improves safety has been challenged. It is apparent from these findings that what the safety personnel actually do is more important than how many are employed. This is a major finding in relation to theory and practice which challenges previous research.
Addressing patients’ colorectal cancer needs in preoperative education
Authors: Jane Spalding Nicola , McCulloch Jane , Mary Poland Fiona , Gregory Sheila , Sargen Kevin , Vicary Penny
Published: September 2013

Purpose

– The purpose of this paper is to understand and develop ways to enhance patients’ experiences of preoperative education received prior to surgery for colorectal cancer.

Design/methodology/approach

– Based in the UK, three-action research cycles were undertaken to evaluate preoperative education, identify changes seen by patients and staff as likely to improve the service and to re-evaluate such changes following implementation. Data in each cycle were collected from: observations of clinic interactions; patient questionnaires; individual semi-structured interviews with multidisciplinary colorectal unit staff; longitudinal semi-structured interviews with patients and carers pre-surgery, two weeks post-surgery and 12 weeks post-surgery; patient and carer focus groups post-surgery; and existing educational material.

Findings

– In total, 138 participants shared their experiences of either giving or receiving preoperative education. Findings were themed into why patients want preoperative education, and patients’ views of the educational processes.

Practical implications

– Patients emphasised the need for educational provision to be fully understandable, comprehensive and client-centred using a range of communication processes. Patients emphasised the need for educational provision to be more fully understandable, comprehensive and client-centred and that important messages should be reinforced using a range of media. At a time of many uncertainties for patients’ lives, such education needed to encompass the experiences patients could expect, delivered by confident healthcare professionals.

Originality/value

– Contextualising understanding and facilitating their own actions, enabled patients to regain control in circumstances particularly disruptive of bodily and other life routines. Establishing a sense of control is confirmed as important for patient's wellbeing in preparing for surgery and postoperative rehabilitation.
Main Annulus Gas Path Interactions—Turbine Stator Well Heat Transfer
Authors: Dixon Jeffrey A. , Guijarro Valencia Antonio , Coren Daniel , Eastwood Daniel , Long Christopher
Published: September 2013

This paper summarizes the work of a five year research program into the heat transfer within cavities adjacent to the main annulus of a gas turbine. The work has been a collaboration between several gas turbine manufacturers, also involving a number of universities working together. The principal objective of the study has been to develop and validate computer modeling methods of the cooling flow distribution and heat transfer management, in the environs of multistage turbine disk rims and blade fixings, with a view to maintaining component and subsystem integrity, while achieving optimum engine performance and minimizing emissions. A fully coupled analysis capability has been developed using combinations of commercially available and in-house computational fluid dynamics (CFD) and finite element (FE) thermomechanical modeling codes. The main objective of the methodology is to help decide on optimum cooling configurations for disk temperature, stress, and life considerations. The new capability also gives us an effective means of validating the method by direct use of disk temperature measurements, where otherwise, additional and difficult to obtain parameters, such as reliable heat flux measurements, would be considered necessary for validation of the use of CFD for convective heat transfer. A two-stage turbine test rig has been developed and improved to provide good quality thermal boundary condition data with which to validate the analysis methods. A cooling flow optimization study has also been performed to support a redesign of the turbine stator well cavity to maximize the effectiveness of cooling air supplied to the disk rim region. The benefits of this design change have also been demonstrated on the rig. A brief description of the test rig facility will be provided together with some insights into the successful completion of the test program. Comparisons will be provided of disk rim cooling performance for a range of cooling flows and geometry configurations. The new elements of this work are the presentation of additional test data and validation of the automatically coupled analysis method applied to a partially cooled stator well cavity (i.e., including some local gas ingestion) and also the extension of the cavity cooling design optimization study to other new geometries.
Direct Numerical Simulation of Stagnation Point Heat Transfer Affected by Varying Wake-Induced Turbulence
Authors: Venema Lars , von Terzi Dominic , Bauer Hans-Jörg , Rodi Wolfgang
Published: September 2013

In the present study the flow and heat transfer in a tandem cylinder setup are simulated by means of embedded direct numerical simulation (DNS). The influence of wake turbulence on the heat transfer in the stagnation region of the rear cylinder is investigated. The oncoming flow is varied by increasing the distance between the two cylinders, causing a change of the turbulent wake characteristics and the heat transfer. The data of both simulations show good agreement with an existing experimental correlation in the literature. For the small wake generator distance, a clear shift of the maximum heat transfer away from the stagnation line is observed. This shift is less pronounced for the larger distance.
A Computational Fluid Dynamics Study of Circumferential Groove Casing Treatment in a Transonic Axial Compressor
Authors: Chen Haixin , Huang Xudong , Shi Ke , Fu Song , Ross Mark , Bennington Matthew A. , Cameron Joshua D. , Morris Scott C. , McNulty Scott , Wadia Aspi
Published: September 2013

Numerical investigations were conducted to predict the performance of a transonic axial compressor rotor with circumferential groove casing treatment. The Notre Dame Transonic Axial Compressor (ND-TAC) was simulated at Tsinghua University with an in-house computational fluid dynamics (CFD) code (NSAWET) for this work. Experimental data from the ND-TAC were used to define the geometry, boundary conditions, and data sampling method for the numerical simulation. These efforts, combined with several unique simulation approaches, such as nonmatched grid boundary technology to treat the periodic boundaries and interfaces between groove grids and the passage grid, resulted in good agreement between the numerical and experimental results for overall compressor performance and radial profiles of exit total pressure. Efforts were made to study blade level flow mechanisms to determine how the casing treatment impacts the compressor's stall margin and performance. The flow structures in the passage, the tip gap, and the grooves as well as their mutual interactions were plotted and analyzed. The flow and momentum transport across the tip gap in the smooth wall and the casing treatment configurations were quantitatively compared.
Sensitivity of the Overall Effectiveness to Film Cooling and Internal Cooling on a Turbine Vane Suction Side
Authors: Williams Randall P. , Dyson Thomas E. , Bogard David G. , Bradshaw Sean D.
Published: September 2013

The overall cooling effectiveness for a turbine airfoil was quantified based on the external surface temperature relative to the mainstream temperature and the inlet coolant temperature. This can be determined experimentally when the model is constructed so that the Biot number is similar to that of engine components. In this study, the overall cooling effectiveness was experimentally measured on a model turbine vane constructed of a material deigned to match Bi for engine conditions. The model incorporated an internal impingement cooling configuration. Overall cooling effectiveness and adiabatic film effectiveness were measured downstream of a single row of round holes positioned on the suction side of the vane. Experiments were conducted to evaluate the cooling effects of internal cooling alone, and then the combined effects of film cooling and internal cooling for a range of coolant flow rates. While the adiabatic film effectiveness decreased when using high momentum flux ratios for the film cooling, due to coolant jet separation, the overall cooling effectiveness increased at higher momentum flux ratios. This increase was due to increased internal cooling effects. Overall cooling effectiveness measurements were also compared to analytical predictions based on a 1D thermal analysis using measured adiabatic film effectiveness and overall cooling effectiveness without film cooling.
Rim Seal Ingestion in a Turbine Stage From 360 Degree Time-Dependent Numerical Simulations
Authors: Wang Cheng-Zhang , Mathiyalagan Senthil Prasad , Johnson Bruce V. , Glahn J. Axel , Cloud David F.
Published: September 2013

Numerical simulations of turbine rim seal experiments are conducted with a time-dependent, 360 deg computational fluid dynamics (CFD) model of the complete turbine stage with a rim seal and cavity to increase understanding of the rim seal ingestion physics. The turbine stage has 22 vanes and 28 blades and is modeled with a uniform flow upstream of the vane inlet, a pressure condition downstream of the blades, and three coolant flow conditions previously employed during experiments at Arizona State University. The simulations show the pressure fields downstream of the vanes and upstream of the blades interacting to form a complex pressure pattern above the rim seal. Circumferential distributions of 15 to 17 sets of ingress and egress velocities flow through the rim seal at the two modest coolant flow rate conditions. These flow distributions rotate at approximately wheel speed and are not equal to the numbers of blades or vanes. The seal velocity distribution for a high coolant flow rate with little or no ingestion into the stator wall boundary layer is associated with the blade pressure field. These pressure field characteristics and the rim seal ingress/egress pattern provide new insight to the physics of rim seal ingestion. Flow patterns within the rim cavity have large cells that rotate in the wheel direction at a slightly slower speed. These secondary flows are similar to structures noted in previous a 360 deg model and large sector models but not obtained in a single blade or vane sector model with periodic boundary condition at sector boundaries. The predictions of pressure profiles, sealing effectiveness, and cavity velocity components are compared with experimental data.
Optimization of Turbomachinery Flow Surfaces Applying a CFD-Based Throughflow Method
Authors: Pasquale David , Persico Giacomo , Rebay Stefano
Published: September 2013

This work proposes an automated strategy for the preliminary design of turbomachinery, based on the application of a throughflow code and of a highly flexible and efficient optimization strategy. The code solves for the circumferentially-averaged flow equations, including the effects of aerodynamic and friction forces and of blade thickness; the outcome of the code is the flow distribution on the meridional surface. The fluid-dynamic solver is coupled with the optimization tool in order to determine the “optimal” mean flow surface, as a result of a multiobjective optimization procedure, in which nonconcurrent goals are simultaneously considered. A global optimization strategy is applied, based on the combination of a Genetic Algorithm with a metamodel to tackle the computational cost of the process. The optimization method is applied to a low speed axial compressor, for which the optimization goals are the minimization of aerodynamic loss and discharge kinetic energy at the exit of the stage, as well as the uniformity of work exchange along the blade span. The method proves to match all the objectives, providing a clear improvement with respect to classical and well-established design methods. The optimization provided by the automated design is finally assessed by high-fidelity calculations performed with a fully three-dimensional CFD code on both the baseline and optimized machine configurations. Improvements are confirmed for all the goals specified in the optimization strategy, resulting in a more efficient machine.
An Actuator Disk Model of Incidence and Deviation for RANS-Based Throughflow Analysis
Authors: Rosa Taddei Simone , Larocca Francesco
Published: September 2013

Reynolds-averaged Navier–Stokes (RANS) equations with blade blockage and blade force source terms are solved in the meridional plane of complete axial flow turbomachinery using a finite-volume scheme. The equations of the compressible actuator disk (AD) are introduced to modify the evaluation of the convective fluxes at the leading and trailing edges (LEs and TEs). An AD behaves as a compact blade force which instantaneously turns the flow with no production of unphysical entropy. This avoids unphysical incidence loss across the LE discontinuity and allows for application of all of the desired deviation at the TE. Unlike previous treatments, the model needs no handmade modification of the throughflow (TF) surface and does not discriminate between inviscid and viscous meridional flows, which allows for coping with strong incidence gradients through the annulus wall boundary layers and with secondary deviation. This paper derives a generalized blade force term that includes the contribution of the LE and TE ADs in the divergence form of the TF equations and leads to generalized definitions of blade load, blade thrust, shaft torque, and shaft power. In analyzing a linear flat plate cascade with an incidence of 32 deg and a deviation of 21 deg, the proposed model provided a 105 reduction of unphysical total pressure loss compared to the numerical solution with no modeling. The computed mass flow rate, blade load, and blade thrust showed excellent agreement with the theoretical values. The complete RANS TF solver was used to analyze a four-stage turbine in design and off-design conditions with a spanwise-averaged incidence of up to 2 deg and 43 deg, respectively. Compared to a traditional streamline curvature solution, the RANS solution with incidence and deviation modeling provided a 0.1 to 0.7% accurate prediction of mass flow rate, shaft power, total pressure ratio, and adiabatic efficiency in both the operating conditions. It also stressed satisfactory agreement concerning the spanwise distributions of flow angle and Mach number at LEs and TEs. In particular, secondary deviation was effectively predicted. The RANS solution with no modeling showed acceptable performance prediction only in design conditions and could introduce no deviation.
Students Propose Genetic Solutions to Societal Problems
Authors: Wick Sue , Decker Mark , Matthes David , Wright Robin
Published: September 2013

The Genetic Engineering Proposal Project, an IBI prize-winning module, teaches biology students to devise innovative bioproducts or solutions to environmental or health problems.
Abnormal Grain Growth Induced by Cyclic Heat Treatment
Authors: Omori Toshihiro , Kusama Tomoe , Kawata Shingo , Ohnuma Ikuo , Sutou Yuji , Araki Yoshikazu , Ishida Kiyohito , Kainuma Ryosuke
Published: September 2013

Making the Grain

Most metals contain a large number of ordered crystalline regions that are separated by disordered grain boundaries. If the material is annealed at elevated temperatures, the larger grains will grow uniformly at the expense of the smaller ones. This process slows down over time, making it hard to create very large grains. Abnormal grain growth, in which a few of the crystalline regions grow much faster and larger than the others, can occur if the material is put through a complex annealing process involving straining of the samples.

Omori
et al.

(p.
1500
; see the Perspective by

Taleff and Pedrazas

) find that a much simpler and shorter annealing process can trigger abnormal grain growth in copper-based shape-memory alloys. Thermal cycling between a high-temperature single-phase region and a lower-temperature two-phase region generated dislocations at low temperatures and grain growth on heating. Because this method does not require external straining of the sample, it is not limited to thin sheets or wires.