bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Ply Sequence on the Elastic Properties of Laminated Composites
Authors: Amaro A.M. , Antunes F.V. , Ramalho A.
Published: January 2019

Composite materials are mostly submitted to dynamic loads, because of their excellent specific strength and stiffness, therefore the resonant technique is adequate for the determination of stiffness properties. Three plates of similar carbon-epoxy composites with distinct fibre orientations were studied with this technique. The effect of stacking sequence on the rigidity of laminated composites was investigated A significant influence of this material parameter on in-plane elastic properties was found, allowing optimization of stiffness for a particular application.
A Proposed Fabrication Method of Novel PCL-GEL-HAp Nanocomposite Scaffolds for Bone Tissue Engineering Applications
Authors: Hamlekhan A. , Mozafari M. , Nezafati N. , Azami M. , Hadipour H.
Published: January 2019

In this study, poly(∊-caprolactone) (PCL), gelatin (GEL) and nanocrystalline hydroxyapatite (HAp) was applied to fabricate novel PCL-GEL-HAp nanaocomposite scaffolds through a new fabrication method. With the aim of finding the best fabrication method, after testing different methods and solvents, the best method and solvents were found, and the nanocomposites were prepared through layer solvent casting combined with freeze-drying. Acetone and distillated water were used as the PCL and GEL solvents, respectively. The mechanical test showed that the increasing of the PCL weight through the scaffolds caused the improvement of the final nanocomposite mechanical behavior due to the increasing of the ultimate stress, stiffness and elastic modulus (8 MPa for 0% wt PCL to 23.5 MPa for 50% wt PCL). The biomineralization investigation of the scaffolds revealed the formation of bone-like apatite layers after immersion in simulated body fluid (SBF). In addition, the in vitro cytotoxity of the scaffolds using L929 mouse fibroblast cell line (ATCC) indicated no sign of toxicity. These results indicated that the fabricated scaffold possesses the prerequisites for bone tissue engineering applications.
A Study on the Dielectric Behaviour of Epoxy/Hafnium Oxide Nanopowder Composites
Authors: Georga S.N.
Published: January 2019

The dielectric response of 10 and 15phr epoxy/HfO2 nanocomposite systems has been studied in a wide frequency and temperature range. The experimental results show an enhancement of the dielectric permittivity with increasing filler concentration. The dielectric spectra reveal the presence of α-relaxation and a weak MWS effect. In the high frequency range the real part of the electrical conductivity obeys the Universal Dielectric Response (UDR), whereas at low frequencies and high temperatures DC conductivity is observed. VFT (Vogel-Fulcher-Tamann) parameters are calculated for all measured specimens.
Using Digital Image Correlation Techniques for Damage Detection on Adhesively Bonded Composite Repairs
Authors: Caminero M.A. , Pavlopoulou S. , López-Pedrosa M. , Nicolaisson B.G. , Pinna C. , Soutis C.
Published: January 2019

The use of composite materials in aircraft industry has risen significantly in recent years. Bonded patch repair technologies provide an alternative to mechanically fastened repairs with significantly higher performance. In this work, the behaviour of scarf-type bonded patches in laminated composites are monitored using full-field measurement methods based on Digital Image Correlation (DIC) techniques which are validated against Lamb wave propagation analysis. The current work focuses on the performance and the on-line monitoring of the adhesively bonded patches in composite plates subjected to tensile loading
Study of Cutting Force and Surface Roughness in Machining of ZA43 SiC Particulate MMC
Authors: Marigoudar Rajaneesh N , Sadashivappa Kanakuppi
Published: January 2019

The present paper reveals the machinability properties of Zinc - Aluminium alloy reinforced with SiC particulate metal matrix composite. The composite was prepared using liquid metallurgy technique. In this study, MMC Zn-57%Al-43% was fabricated by SiC (1% and 5%) with average particle size of 30μm. Full factorial design was used to plan the experiments (54 trials) and ANOVA method was used to analyze the results. Coated carbide tool CCMT9T304 was used in the experiment. Dry turning was employed with spindle speeds of 32, 48 and 73 m/min and feed rates of 0.2, 0.3 and 0.5 mm/rev and depths of cut of 0.25, 0.5 and 0.75 mm. It was observed from the results that cutting force was significantly affected by speed, feed and depth of cut where as surface finish was affected greatly by speed and feed. Depth of cut has less effect on surface finish.
Fatigue Behaviour of a Hybrid Particle Modified Fiberglass/Epoxy Composite under a Helicopter Spectrum Load Sequence
Authors: Jagannathan N. , Bojja Ramesh , Manjunatha C.M. , Taylor A.C. , Kinloch A.J.
Published: January 2019

The fatigue life of a glass fibre reinforced plastic (GFRP) hybrid composite containing 9 wt.% of rubber microparticles and 10 wt.% of silica nanoparticles, under a standard helicopter rotor spectrum load sequence was determined and observed to be about three times higher than that of GFRP with unmodified epoxy matrix. The underlying mechanisms for the observed improvements in spectrum fatigue life of GFRP composite with the hybrid matrix are discussed.
Mechanical Properties and Wear Behaviour of Al2O3/SiCp Reinforced Aluminium-Based MMCs Produced by the Stir Casting Technique
Authors: Altinkök Necat
Published: January 2019

In this study, initially Al2O3/SiC powder mix was prepared by reacting of aqueous solution of aluminium sulphate, ammonium sulphate and water containing SiC particles at 1200°C. 10 wt% of this hybrid ceramic powder with different sized SiC particles was added to a liquid Al matrix alloy during mechanical stirring between solidus and liqudus under inert conditions. Then hybrid Metal Matrix Composites (MMCs) was produced. The effect of reinforced particle size on tensile strength, bending strength, hardness resistance and wear resistance properties of hybrid reinforced MMCs were investigated. The mechanical test results revealed that bending, tensile strength and hardness resistance of the composites increased with decrease in ductility, with decrease size of the reinforcing SiC particulates in the aluminium alloy metal matrix. The wear behaviour of the hybrid ceramic reinforced aluminium matrix composites was investigated using pin-on-disc test at room temperature under dry conditions. Wear tests showed that the wear resistance of MMCs increased with increasing reinforced Al2O3/SiC particle size. Comparing the fine particle size MMCs with the coarse particle size MMCs were easily pulled out whole from the matrix. Microstructural examination showed that as well as coarse SiC particle reinforcement, a fine alumina particle reinforcement phase was observed within the aluminium matrix (A332).
Thermal Endurance Testing of Kevlar Fabric/Phenolic Sandwich Composite Protecting the Electronics of a Search and Rescue Robot
Authors: Stopforth Riaan , Adali Sarp
Published: January 2019

Thermal endurance of sandwich panels made of a Kevlar fabric/phenolic composite material has been studied via flame tests. The panels are to be used for the protection of the electronic instruments of robots used for Urban Search and Rescue which are employed under severely adverse operational conditions. As such it is important to determine the time duration that the temperatures will remain at allowable levels inside the robot. These panels are required to be light and have low heat transfer capability. The results show that a combination of composite material design coupled with heat resistant coating provides sufficient insulation to maintain suitable working temperatures for the protected components.
A Multi-Scale Approach to Predict the Impact Resistance of Braided Composites using Progress Failure
Authors: Lei Xu , Hayat Khazar , Ha Sung Kyu
Published: January 2019

A novel multi-scale approach based on micromechanics of failure together with the progressive damage models of the fibre and matrix constituents is presented to predict the impact resistance of braided composites. The meso- and micro-scale unit-cells of the braided composites with both thermosetting and thermos-plastic resin systems, were employed, and the effective properties of the braided tows, in the meso unit cell, were updated using the micro unit cell for which the degradation of constituent material properties were incorporated.
Displacement Analytical Solution of a Circular Hole in Layered Composite Materials considering Shear Stress Effect
Authors: Zhang Zhizeng , Li Xiaochang
Published: January 2019

Layered composite materials can be treated as transverse isotropy in mechanics. According to basic equations of transverse isotropy, the compatibility equation in polar coordinates is firstly formulated. Then the analytical solution for a deep circular hole considering shear stress and two unequal normal stresses in layered composite materials is derived. The solution shows that the radial displacement is affected by the elastic modulus and Poisson ratio in both the isotropic plane and the direction of symmetry axis in spite of the hypothesis that the hole transect is parallel to the isotropic plane.
Finite Element Model for Analysis of the Spatial Interfacial Debonding of FRP from Concrete
Authors: Zhang Feng , Gao Lei
Published: January 2019

The debonding of the FRP plate from concrete and crack-propagation processes are complex and the current research studies regarding this debonding mechanism are insufficient and not comprehensive. This work proposes a plane stress model along with equal width and different width FRP to concrete models to simulate the debonding and crack-propagation processes are presented. The longitudinal and horizontal stress distributions were analysed and the FRP to concrete width effect and FRP thickness parameters were also studied by means of the proposed three-dimensional finite element model. The results show that the different width 3D model is optimal for analysing the spatial interfacial debonding of FRP from concrete. The concrete surface horizontal stress distribution along the length of the concrete substrate could judge the effective bond length. Both the normal stress and shear stress are mainly divided into the following two small central stress regions under the PRP plate: a high stress gradient region near the FRP plate edge and a stress-free region near the concrete edge. The debonding strength and the stiffness of the bonding interface increase with the width of the FRP plate and the FRP plate thickness. The stress range and magnitude are strongly dependent on the width of the FRP plate. Debonding begins at the FRP plate edge; the thicker FRP plate more easily exhibits debonding.
Enhanced Drag Reduction Performance of Nanocomposites: The Effects of Surface Modification of Nano Silica
Authors: Dai Xiaodong , Zhang Guicai , Li Bing , Ge Jijiang , Wang Xuewu , Yin Shuming
Published: January 2019

In this paper, nanocomposite was synthesized with nano silica and poly-α-olefin, and the effects of surface modification to the nano silica on its drag reduction performance were investigated. The dosage coupling agent, Y-aminopropyltriethoxysilane, and the modification temperature were studied intensively through surface hydroxyl and oil adsorption analysis. The test results indicated that the hydroxyl number of the silica was decreased by Y-aminopropyltriethoxysilane modification, with improved lipophilicity and oil adsorption. At 50°C, the optimum Y-aminopropyltriethoxysilane dosages were 15% for Nano-Si-10, 5% for Nano-Si-20, and 10% for Degussa-R972. The modification significantly changed the nano silica surface properties and enhanced the interaction with poly-α-olefin. Through drag reduction and shear resistance tests by rotating disk 40 mins degradation and testing loop 2 times shearing, it was shown that the nanocomposite possessed good drag reduction and excellent shear resistance properties.
Flexural Behaviour of CFRP/MG Hybrid Laminates with Different Layers Thickness
Authors: Wu Xuan , Pan Yingcai , Wu Guoqing , Huang Zheng , Tian Rui , Sun Siqiang
Published: January 2019

Three different types of fibre metal laminates (FMLs) with varying layers thickness, consisting of carbon fibre reinforced polymer (CFRP) prepregs and magnesium alloy sheets, were prepared by a hot-press process. The flexural behaviour of the FMLs were investigated using a three point flexural test method, to investigate the effect of layer thickness on flexural behaviour of FMLs while maintaining a constant metal volume fraction and constant overall thickness in the design process. The results show that the flexural modulus of the FMLs decreases in an almost linear manner with the decrease of layer thicknesses, yet no clear differences were observed in the flexural strength. Decreasing the layer thickness causes the transition of failure zone from compression region to tension region, which results in the appearance of two similar peak stresses.
Experimental Study and Theoretical Analysis on Flexural Mechanical Propertiesof Reinforced Timber Beams
Authors: Xueyu Xiong , Yiqingzi Wang , Rongjun Xue , Xuanxing Lu
Published: January 2019

As Chinese architecture masterpiece, ancient Hui-style architecture is the admiration for Chinese and foreign master builders. According to the bending test, the theoretical calculations and Abaqus finite element analysis on 5 Hui-style architecture beams, this paper points out the differences between un-reinforced beams and reinforced beams on ultimate bearing capacity, deflection and other performance indicators. The reinforcement methods of embedding steel bars, embedding CFRP bars and pasting CFRP plate can respectively improve the ultimate bearing capacity by 20.2%, 32.6% and 37.0%. Based on the plane section assumption and considering thereduction of tensile strength causedby wood knots and defects in tension zone, this paper predicts failure modes of the test beams may occur, and gives the ultimate bearing capacity of different failure modes. In addition, this paper uses the Abaqus finite element software for simulating test beams, and the development trend of load-deflectioncurve between the test and numerical simulation are in good agreement, providing reference for further research of Hui-style architecture.
Damage and Failure Analysis of Filament Wound Composite Structure considering Fibre Crossover and Undulation
Authors: Shen Chuangshi , Han Xiaoping
Published: January 2019

The occurrence of fibre crossover and undulation(FCU) is inherent of the filament windingproc ess. However, the study on the effect of FCU on the mechanical performance and failure of filament wound composite(FWC) structure were mainly experimental research. So in this paper, a macro-meso failure analysis model for FWC considering FCU is established based on Puck, Hashin failure criterion and Linde stiffness degradation model. The influence of fibre crossove r and undulation on the stiffness failure is calculated and analyzed. The numerical results show that the strain in FCU region is higher by about 1.07–1.13 times than it in laminate region, the FCU have a certain influence on the failure strength of filament wound composite and the failure position of FWC under axial tensile load and internal pressure is mainly located FCU region and the failure position under axial compressive load is related to the winding angle.
Effect of the Flux on the Fire-Resistance Properties of Cerami-Fiable Epdm Rubber Composites
Authors: Zou Zhenyue , Qin Yan , Liu Liangdian , Huang Zhixiong
Published: January 2019

In this paper, two kinds of glass frit and zinc borate as fluxes were used to prepare ceramifiable EPDM rubber composites, and the mechanical test, SEM, XRD and TG-DSC were used to study the effects of fluxes on the thermal stability and pyrolysis performance of composite materials. The results showed that the addition of the three kind of fluxes helped the filler to form a large amount of liquid phase structure at high temperature, and then a good ceramic structure formed to improve the thermal stability of the composite material and the bending strength of the pyrolysis product. The XRD analysis showed that the main phases after pyrolysis of composite materials adding glass frit A were forsterite and quartz, and the main phases after pyrolysis of composite materials adding glass frit B or zinc borate were spinel and quartz.
Environmental Degradation Studies of the Interface in Single-Filament Graphite / Epoxy Composites using Laser Raman Spectroscopy
Authors: Amer M.S. , Koczak M.J. , Galiotis C. , Schadler L.S.
Published: January 2019

To design an interface with specific environmental resistance, it is essential to understand the fundamental mechanisms of interfacial degradation. To this end, Laser Raman Spectroscopy (LRS) has been used to monitor the interfacial behavior in graphite / epoxy single-filament composites as a function of environmental exposure. Preliminary results of the observed changes in the interfacial behavior after exposure of the composite to water and air at 100°C are reported.
Thermal Expansion of Transcrystalline Strips
Authors: Klein Nava , Marom Gad
Published: January 2019

The results of a direct measurement of the longitudinal thermal expansion coefficient of an isolated transcrystalline layer are reported below for a nylon 66 transcrystalline strip grown on a Kevlar 29 aramid fibre. It is shown that the expansivity of the transcrystalline layer is more than an order of magnitude smaller than that of the bulk crystallized matrix. It is hypothesized that the transcrystalline layer relieves thermal stresses in composite materials by matching the expansivities of the constituents.
Mechanical Properties of Welt Knitted Fabric Reinforced Composites
Authors: Hamada Hiroyuki , Nakai Asami , Fujita Akihiro , Inoda Miyako
Published: January 2019

In this paper, welt knitted fabric reinforced composites were fabricated and its tensile properties were measured. Changing knitted structure from plain knit to welt knit caused changing mechanical properties, particularly isotropic tensile strength could be obtained. The fracture mode of welt knitted fabric reinforced composite was similar that of plain knitted fabric reinforced composite.
Nanocomposites Produced by Growth of Hydroxyapatite onto Silica Particles Prepared by the Sol-Gel Method
Authors: Rodríguez R. , Coreño J. , Arenas J.A. , Castaño V.M.
Published: January 2019

The growth of hydroxyapatite, a calcium phosphate, on silica particles prepared by the sol-gel method is reported. The size of the silica sols was controlled by changing the pH of water before the mixing with the alcoxide. Particle size profiles of sols were obtained by using dynamical light scattering. The characterisation of the composites, of nanometer sizes, was performed by employing X-ray diffraction, scanning electron microscopy and Raman spectroscopy.
Damage Modes in Impact Loading of Glass Woven Fabric Composites
Authors: Hirai Yasunobu , Hamada Hiroyuki , Kim Jang-Kyo
Published: January 2019

Instrumented impact test was used to assess the impact performance of E-glass woven fabric reinforced vinyl ester matrix composites. Evaluation of the damages with the aid of optical microscopy revealed substantial differences in the shape, mode and area of damage between the front and back surfaces of impact and between laminates with different fibre surface treatments. Apart from the extensive delamination in the central damage region, interface debonding occurred along the warp and weft directions in the surrounding regions near the back face of impact which contributed significantly to the total damage area of the laminate.
Preparation and Characterization of Nanocomposite Films
Authors: Carotenuto G. , Nicolais L.
Published: January 2019

The incorporation of nanosized inorganic particles into a polymeric matrix represents the most important problem in the nanocomposite fabrication. Success in manufacturing materials for optical devices can be achived only if the particle aggregation is avoided. This paper describes the preparation of a polymeric nanocomposite containing a well-dispersed red pigment synthesized using nanosized titania particles.
Effect of Hydrothermal Exposure on Interfacial Stress Transfer in Graphite/Epoxy Composites loaded in Compression
Authors: Amer Maher S. , Schadler Linda S.
Published: January 2019

The effect of hydrothermal exposure on the ability of the interface to transfer shear stresses in graphite/epoxy composites under compression is reported. Hydrothermal exposure caused a drop in the ability of the interface to transfer shear stresses from 130 to 15 MPa and increase in the average fragment length from 80 to 1000 μm. The impact of hydrothermal exposure on the composite interfacial behavior is compared with that for composites loaded in tension. The results showed that the interfacial degradation is more severe for composites loaded in compression.
Thermoelastic Behavior of the Single Carbon Fibre/Polycarbonate Microcomposites
Authors: Privalko Valery P. , Sukhorukov Dmitry I. , Karger-Kocsis József
Published: January 2019

Stretching calorimetry technique was used to evaluate Young's moduli ( E), linear expansivities (α L) and internal energy changes (Δ U) in stretching/contraction cycles for single carbon fiber/ polycarbonate (CF/PC) microcomposites. Within the interval of elastic strains, microcomposites with both sized and unsized CF were characterized by significantly higher values of E and Δ U and by lower values ofα L compared to the plain PC matrix. The results obtained suggest the formation of interfacial boundary PC layers with changed structure around CF which affect the thermoelastic properties of the CF/PC microcomposites.
Towards Assessment of Reliable Mechanical Properties for Knitted Fabric-Reinforced Thermoplastic Composites
Authors: Karger-Kocsis J.
Published: January 2019

Since the mechanical performance of knitted fabric-reinforced thermoplastic (KFRT) composites is closely matched to composite laminates composed of unidirectional (UD) plies, attempts are made to adopt the characterization methods of the latter also for KFRT. This approach is not straightforward, and even not viable in many cases due to a peculiar load transfer and damage development associated with the knit structure. Although produced in plane, the knitted layers in the composites are never planar anymore, but tend to adopt a higher than two-dimensional (2D) reinforcing sructure. That is the main reason why established testing techniques which work well for advanced composites fail for KFRT. In order to determine reliable mechanical parameters for KFRT, the size of the damage zone (where stress transfer occurs) should also be considered. This paper lists some suitable measuring techniques and related aspects based on the experience gained on multilayer, plain weft knit-reinforced composites with various thermoplastic matrices.
Computational Engineering Homogenisation of Steel Reinforced Concrete Plates
Authors: Kamiñski Marcin
Published: January 2019

The main subject of the paper is the application of the homogenisation method to the analysis of the elastostatic problem for the steel reinforced concrete plate. The upper and lower bounds on the effective elasticity tensor components as well as direct approximation of the tensor are used to build up the computational model of the structure. The results of numerical analysis are compared against the experimental data. The convergence of experimental and computational data for the real and homogenised composite plate confirms the effectiveness of the homogenisation method applied in the analysis of steel-reinforced uncracked concrete structures. To verify the generality of this approach, analogous tests should be carried out for other types of engineering composite structures, especially in continuous non-linear range.
Natural Vegetable Fibre / Plasticised Natural Vegetable Fibre - a Candidate for Low Cost and Fully Biodegradable Composite
Authors: Lu Xun , Zhang Ming Qiu , Rong Min Zhi , Shi Guang , Yang Gui Cheng , Zeng Han Min
Published: January 2019

A novel fibre composite consisting of natural vegetable fibre as the reinforcer and plasticised natural vegetable fibre as the matrix was studied. By means of cyanoethylation and chlorination, pine sawdust and chopped sisal were converted into thermoplastics and then compounded with sisal and ramie fibres. The natural fibre composite not only exhibits properties similar to those of conventional fibre composites, but also is characterised by easy processing, enviromental frendliness, low cost and capability of tailoring property due to the physically heterogeneous nature.
Strengthening and Strain Sensing of Rectangular Concrete Beam Using Composites and Fbg Sensors
Authors: Lau Kin-tak , Zhou Li-min , Ye Li
Published: January 2019

In this paper, a state-of-art report of an experimental investigation on the mechanical properties of the laboratory size notched-concrete beams strengthened by using fibre woven composites is presented. Fibre-optic Bragg grating (FBG) sensors have been adhered on the concrete surface before laying up the composites to monitor the strain changes at the interface when the concrete beam was subjected to three-point bending load after strengthening. The electrical strain gauges were also used to measure the surface strain of the composites and compare the results from the internal sensors. The results show that the overall flexural strengths of the strengthened specimens are increased compared with its un-strengthened status. Concrete and bonding failures were observed when the thick reinforcement was used. In addition, the results obtained from the sensor reveal that the strain at the interface of bond was higher than that measured on the surface of the composite reinforcement. High strain was measured from the sensor when debond at the interface occurred.
Measuring Celebrity Equity: Unearthing the Consumer Knowledge Structure Associations
Authors: Ghuman Mandeep Kaur , Parmar Yadvinder , Mann Bikram Jit Singh
Published: January 2019

The qualitative research aims to develop an understanding of how consumers view the celebrity as a brand and also to measure and compare the celebrity equities. This research applies associative network theory to identify the celebrity association networks residing in the minds of the consumers using Brand Concept Maps (BCMs) methodology. It also measures the celebrity equity by measuring the relative strength, favourability and uniqueness of the associations. Three celebrities from different professions are selected for this study. Data for the construction of BCMs have been obtained from 50 respondents. The associations are shown on BCMs, and their structure has been analysed using general and central characteristics. Celebrity equity is measured using Krishnan (1996, International Journal of Research in Marketing, 13(4), 389–405) methodology. The results reveal that consumers link five categories of associations with a celebrity, namely professional associations, public-image-related associations, social responsibility- and ethics-related associations, lifestyle associations and negative associations. Further, the celebrities are found to have strong brand equities, but their relative equities differ from each other. This study reveals that the managers need to consider a wide range of associations for measuring celebrity equity. It also provides academicians and celebrity managers with a new methodology for measuring celebrity equity.
Is multiple viral infection a predictor of severity in children with acute bronchiolitis?
Authors: Yurtseven Ali , Turan Caner , Elibol Pelin , Çiçek Candan , Saz Eylem Ulas
Published: January 2019

Background:

Acute bronchiolitis is a common cause of pediatric emergency department admissions in children younger than 2.

Objectives:

The study aimed to compare the outcomes and the severity of bronchiolitis in young children with multiple simultaneous respiratory virus infections to those with single virus infection and no virus identified group.

Methods:

Patients with moderate and severe bronchiolitis who visited our emergency department between November 2016 and May 2017 had nasopharyngeal swab samples results tested by multiplex polymerase chain reaction were included in the study. Patients’ characteristics, clinical severity of illness, and outcome (pediatric emergency department discharge, admission to ward or pediatric intensive care unit) were compared with the detected viral agents.

Results:

A total of 241 patients were included in the study. The mean age was 7.8 ± 2.6 months and 147 (61%) were male. Respiratory syncytial virus was the most common detected viral agent in 108 (39%) cases followed by human rhinoviruses in 67 (24%). Respiratory syncytial virus was found more frequently in February and March (p = 0.002). Leukocytosis and pneumonia were more likely observed in patients with only human rhinoviruses (+) subjects (p = 0.010 and p = 0.015, respectively). Intensive care hospitalization rate (16%) was higher in patients with multiple viral agents (p = 0.004).

Conclusions:

Respiratory syncytial virus remains the most common detected viral agent in acute bronchiolitis patients. While the pathogens detected were seasonally different, there was a significant relationship between leukocytosis, bacterial pneumonia, and detected viral agents. The disease was more severe in patients with multiple viral agents.
Living With an Intestinal Stoma: A Qualitative Systematic Review
Authors: Capilla-Díaz Concepción , Bonill-de las Nieves Candela , Hernández-Zambrano Sandra Milena , Montoya-Juárez Rafael , Morales-Asencio José Miguel , Pérez-Marfil María Nieves , Hueso-Montoro César
Published: January 2019

The main aim of this article is to explore the experiences and life situations of people living with intestinal stomas. Previous studies indicated the need to investigate the concerns of ostomy patients and how these concerns can affect their quality of life and their approaches to the comprehensive conceptualization of the bodily changes. A qualitative systematic review and metasynthesis design was carried out by using the main scientific databases. Original articles from 2002 to 2015 were selected based on their qualitative methodology. Methodological quality was evaluated using the Critical Appraisal Skills Program. The findings were synthesized using the metasynthesis procedure of Sandelowski. The final number of articles included was 95 and 1,982 participants. Regarding the metasummary, the data generated 191 thematic statements that were organized into eight categories. The findings support an explanatory model of the experience of people with ostomy based on three aspects: Acceptance, Adaptation, and Autonomy.
Factors Influencing Participation in Bilateral Interprovincial Agreements: Evidence from China’s Pan Pearl River Delta
Authors: Chen Bin , Ma Jie , Feiock Richard , Suo Liming
Published: January 2019

China’s provincial governments increasingly participate in interprovincial agreements (IPAs) to address regional policy problems. Nevertheless, limited research investigates the determinants of a province’s propensity to engage in bilateral agreements with another province. This article uses network data and employs network regressions to investigate this question in the context of China’s Pan Pearl River Delta (PPRD) regional network governance. We assess the factors that influence participation of bilateral IPAs among PPRD members. Our findings provide evidence that interprovincial participation in bilateral agreements spanning seven policy domains is driven by geographic proximity, economic and political statuses, institutional similarity, and cross-province leadership posting.
The anti-plane shear elasto-static fields near a crack terminating at an isotropic hyperelastic bi-material interface
Authors: Grine Fahmi , Trifa Mohamed , Arfaoui Makrem , Maalej Yamen , Renard Yves
Published: January 2019

In the framework of hyperelasticity, we treat the configuration of a terminated crack at the interface of an incompressible full plane composite. Considering the traction-free boundary conditions, three particular cases are discussed when a cylinder is subjected to an anti-plane shear transformation. Taking all these conditions into account, an asymptotic analysis is performed to identify the sufficient orders contributing to the singular form of the Cauchy stress static fields. Adding to that, an inquiry about the presence of logarithmic singularities was achieved using the approach of Dempsey and Sinclair.
In whose interest? Exploring care ethics within transformative learning
Authors: Smith Sue , Kempster Steve
Published: January 2019

This article brings attention to a seemingly pervasive and underlying assumption in critical management education that transformative learning is a good thing. We explore this assumption through a series of narratives examining the ethics of educators overtly seeking to enable transformative learning with owner-managers in order to impact their businesses. The focus on owner-managers is of significance in terms of transformative learning because of the centrality of the owner-manager to the delicate ecosystem, that is, the small and medium business. The article makes salient relational care in critical management education and the need for educators to engage in a moral dialogue regarding the relational impact of transformative learning in pedagogic designs. Such dialogue necessitates addressing in whose interest is transformative learning being sought, along with the orientation and framing of such learning.
Wind tunnel study of separated and reattaching flows by particle image velocimetry and pressure measurements
Authors: Shu ZR , Li QS
Published: January 2019

This article presents a comprehensive investigation on the separated and reattaching flows over a blunt flat plate with different leading-edge shapes by means of particle image velocimetry and surface pressure measurements. Wind tunnel tests are performed in both smooth and various turbulent flow conditions, and the separated and reattaching flows are examined as a function of Reynolds number ( Re), leading-edge shape, turbulence intensity, and turbulence integral length scale. It is shown through the particle image velocimetry and pressure measurements that the Reynolds number effect is significant regarding the mean vorticity field, but with little effect on the mean velocity field. For the effects of leading-edge shape, the distributions of pressure coefficients respond strongly to the change in leading-edge angle, and both the velocity (streamwise and vertical) and vorticity fields have a clear dependence on the leading-edge shape. For the effects of freestream turbulence, the mean pressure coefficient responds strongly to turbulence intensity, whereas the fluctuating and peak suction pressure coefficients are dependent on both turbulence intensity and integral length scale. The size of the separation bubble contracts aggressively with increasing turbulence intensity, but it remains approximately invariant in response to the change in turbulence scale in the tested range.
Role of employment-related inequalities in young adults’ life satisfaction: A comparative study in five European welfare state regimes
Authors: Vancea Mihaela , Shore Jennifer , Utzet Mireia
Published: January 2019

Aims: There is evidence that young people are less satisfied with their lives when they are unemployed or working in precarious conditions. This study aims to shed light on how the life satisfaction of unemployed and precariously employed young people varies across welfare states with different labour market policies and levels of social protection. Methods: The analyses are based on representative cross-sectional survey data from five European countries (Denmark, the UK, Germany, Spain and the Czech Republic), corresponding to five different welfare state regimes. For economically active young adults ( N=6681), the prevalence ratios of low life satisfaction were estimated through multivariate logistic regressions. Results: In all five countries, unemployed young adults presented a higher prevalence of low life satisfaction. When we compared employees with people with permanent and temporary contracts, the former were more satisfied with their lives only in Germany and the UK, examples of conservative and liberal welfare regimes, respectively. Experience of unemployment decreased young adults’ life satisfaction only in Germany and the Czech Republic, examples of a conservative and an eastern European welfare regime, respectively. In almost all countries, young adults with low economic self-sufficiency presented a higher prevalence of low life satisfaction. Conclusions: There are nuanced patterns of employment type and life satisfaction across European states that hint at welfare state regimes as possible moderators in this relationship. The results suggest that the psychological burdens of unemployment or work uncertainty cannot be overlooked and should be addressed according to different types of social provisions.
Numerical approach to controlling a moving jet’s vibration in an electrospinning system: An auxiliary electrode and uniform electric field
Authors: Chen Rouxi , Wu Yuke , Fan Jie , Wang Liang , Su Zhibo , Qin Liming , Liang Libing , Li Yantao , Cheng Jianhua , Liu Yong
Published: January 2019

A variational principle is established for a moving jet in the electrospinning process to study the vibration property of the jet. A higher accelerated velocity and lower vibration frequency are needed in a multi-needle electrospinning system. This paper introduces an auxiliary electrode to enhance the electric strength, and a numerical analysis is carried out to design an optimal electric field.
Bringing relational comparison into development studies: Global health volunteers’ experiences of Sierra Leone
Authors: Brooks Andrew , Herrick Clare
Published: January 2019

Global health volunteering is premised on a comparative understanding of development: hospitals in developing countries are ‘behind’ modern institutions in developed nations, and sharing volunteers’ skills will enable the latter to ‘catch-up’. We argue for a ‘relational comparison’ in development studies, which draws upon a geographical conception of inequality premised on understanding places in relation to one another rather than reifying differences between countries. We place a particular hospital within a dialectical totality of combined and uneven development. Health workers’ experiences of volunteering in Sierra Leone demonstrate that local problems, including staff shortages and corruption, are enveloped within global processes.
Reading Behavior and Compliance Among Ecuadorian University Students: A National Study
Authors: Ouyang Yuxia , Van Hoof Hubert , Sharma Amit , Cueva Navas Ana , Estrella Duran Mateo , Maldonado Gabriela , Velez Calvo Ximena , Gavilanes Valle Julio
Published: January 2019

A study into reading behavior and reading compliance among 2,600 students in five universities in Ecuador found that their reading behavior and reading compliance were better than among students in the United States, despite the challenges that exist in Ecuadorian higher education. Suggestions for future research, in particular with regard to improving students’ time management skills as a way to enhance their reading compliance, are included.
Behavioral Theory: The Missing Ingredient for Digital Health Tools to Change Behavior and Increase Adherence
Authors: Klonoff David C.
Published: January 2019

Behavioral theory is an important factor for designing digital health tools for diabetes to increase adherence to treatment. Many digital health products have not incorporated this method for achieving behavior change. This oversight might explain the disappointing outcomes of many products in this class. Four theories reported to be capable of enhancing the performance of digital health tools for diabetes include (1) Integrate, Design, Assess, and Share (IDEAS); (2) the Behaviour Change Wheel; (3) the Information-Motivation-Behavioral skills (IMB) model; and (4) gamification. Well-designed digital health tools are most likely to be effective if they are deployed in a patient-centered care setting established upon principles of sound behavioral theory. Behavioral theory can increase the effectiveness of digital tools and promote a receptive environment for their use.
Characterization of cornea-specific bioink: high transparency, improved in vivo safety
Authors: Kim Hyeonji , Park Moon-Nyeo , Kim Jisoo , Jang Jinah , Kim Hong-Kyun , Cho Dong-Woo
Published: January 2019

Corneal transplantation is a typical surgical procedure for severe corneal diseases. However, the waiting time for a donor cornea has gradually increased due to a decrease in supply caused by an aging population and increased cases of laser-based surgeries. Artificial corneas were developed to meet the increase in demand; however, these approaches have suffered from material deterioration resulted by the limited tissue integration. Here, we introduce a cornea-derived decellularized extracellular matrix (Co-dECM) as a bioink for corneal regeneration. The developed Co-dECM bioink had similar quantitative measurement results for collagen and GAGs compared with that of the native cornea and also had the proper transparency for vision. The differentiation potential of human turbinate-derived mesenchymal stem cells (hTMSCs) to a keratocyte lineage was only observed in the Co-dECM group. Moreover, the developed bioink did not have any cytotoxic effect on encapsulated cells for three-dimensional (3D) culture and has great biocompatibility evident by the xeno-implantation of the Co-dECM gel into mice and rabbits for two and one month, respectively. An in vivo safety similar to clinical-grade collagen was seen with the Co-dECM, which helped to maintain the keratocyte-specific characteristics in vivo, compared with collagen. Taken together, the Co-dECM bioink has the potential to be used in various types of corneal diseases based on its corneal-specific ability and design flexibility through 3D cell printing technology.
How recommender systems could support and enhance computer-tailored digital health programs: A scoping review
Authors: Cheung Kei Long , Durusu Dilara , Sui Xincheng , de Vries Hein
Published: January 2019

Objective

Tailored digital health programs can promote positive health-related lifestyle changes and have been shown to be (cost) effective in trials. However, such programs are used suboptimally. New approaches are needed to optimise the use of these programs. This paper illustrates the potential of recommender systems to support and enhance computer-tailored digital health interventions. The aim is threefold, to explore: (1) how recommender systems provide health recommendations, (2) to what extent recommender systems incorporate theoretical models and (3) how the use of recommender systems may enhance the usage of computer-tailored interventions.

Methods

A scoping review was conducted, using MEDLINE and ScienceDirect, to identify health recommender systems reported in studies between January 2007 and December 2017. Information was subsequently extracted to understand the potential benefits of recommender systems for computer-tailored digital health programs. Titles and abstracts of 1184 studies were screened for the full-text screening, in which two reviewers independently selected articles and systematically extracted data using a predefined extraction form.

Results

A total of 26 articles were included for data extraction. General characteristics were reported, with eight studies reporting hybrid filtering. A description of how each recommender system provides a recommendation is described; the majority of recommender systems used messages as recommendation. We identified the potential effects of recommender systems on efficiency, effectiveness, trustworthiness and enjoyment of the digital health program.

Conclusions

Incorporating a collaborative method with demographic filtering as a second step to knowledge-based filtering could potentially add value to traditional tailoring with regard to enhancing the user experience. This study illustrates how recommender systems, especially hybrid programs, may have the potential to bring tailored digital health forward.
Changes in ghrelin and nesfatin-1 in children with growth hormone deficiency treated by recombinant human growth hormone
Authors: Wang Yu , Sun Meng , Wang Xin , Cheng Ya-Ying
Published: January 2019

This study aims to investigate the effects of recombinant human growth hormone (rhGH) on serum nesfatin-1 and ghrelin in children with growth hormone deficiency (GHD), in order to provide a reliable basis for the effectiveness and safety of applying rhGH in treating GHD children in the clinic. A total of 30 GHD pediatric patients were selected as the observation group. According to the peak of GH, these patients were divided into two subgroups: complete absence of growth hormone (CGHD) group and partial absence of growth hormone (PGHD) group. At the same time, 20 healthy children of normal height with matching age and gender were randomly selected as a normal control group. Serum ghrelin and nesfatin-1 levels were detected in children in the control group and observation group before rhGH treatment, and at 3 and 6 months after treatment. After 3 and 6 months of treatment, the height and growth rate of children in the PGHD and CGHD groups significantly increased ( P < 0.05), but their body weights did not significantly change ( P > 0.05), compared with those before treatment. Before treatment, ghrelin was higher in the PGHD group than in the control group, while ghrelin was lower in the CGHD group than in the control group. In addition, nesfatin-1 was higher in these two subgroups, compared with that in the control group. At pretreatment, and after 3  and 6 months of treatment, ghrelin and nesfatin-1 both decreased in the PGHD group, while ghrelin increased and nesfatin-1 decreased in the CGHD group. It was confirmed that ghrelin and nesfatin-1 were closely correlated with GHD. Furthermore, rhGH has a significant effect on children with GHD, and can significantly accelerate the annual growth rate.