bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical Research on Ultimate Bearing Capacity of Pier Strengthened Using Carbon Fiber Reinforced Polymer
Authors: Liu Hanbing , Zheng Jiguang , Sun Yanyi
Published: September 2018

Eccentric compression is one of the major reasons that cause the damage on piers of bridge construction. Making use of the prestressed carbon fiber reinforced polymer (CFRP) to strengthen bridge pier by winding it at a radial direction can give full play to the high strength and high performance of CFRP. As a result, the radial strain of concrete has been greatly constrained and the ultimate bearing capacity of bridge pier has been improved to a large extent. In this paper, the stress state of short column which is strengthened by prestressed CFRP has been analyzed theoretically under the situation of eccentric compression. According to the elastic-plastic theory, the calculation formulas of ultimate bearing capacity of short column strengthened by CFRP have been deduced under eccentric compression. The short column has a circular cross section and is made of reinforced concrete. The failure phenomena and failure mechanism of short column have been minutely analyzed, and the application of the calculation formulas has also been discussed in detail. Further more, consistency has been acquired after comparing this analytical solution with the numerical solution of finite element method (FEM). Therefore, these calculation formulas are not only reasonable and reliable but also have some application value for practical engineering.
Numerical Analysis of Delamination Behavior in Laminated Composite with Double Delaminations Embedded in Different Depth Positions
Authors: Wang R.G. , Zhang L. , Liu W.B. , Zhang J. , Sui X.D. , Zheng D. , Fang Y.F.
Published: September 2018

In this article, the finite element method (FEM) using cohesive element is applied to predict the delamination behavior in laminated composite with double delaminations embedded in different depth positions under compressive load. In particular, compared with single delamination composites, the interaction between delaminations and the complicated propagation behavior are discussed. Furthermore, the study is focused on the significant effects of double delaminations on delamination buckling and growth behavior, such as the distance between double delaminations and the delaminations’ depth position.
Dome Thickness Prediction of Composite Pressure Vessels by a Cubic Spline Function and Finite Element Analysis
Authors: Wang Rongguo , Jiao Weicheng , Liu Wenbo , Yang Fan
Published: September 2018

Nowadays, finite element analysis (FEA) plays an important role in the design of composite pressure vessel. The more accurate finite element models are created, the more precise results could be obtained. In order to create the accurate finite element model for composite pressure vessels, a cubic spline function was developed to predict the dome thickness basing on the principle of total volume preservation of all bands at dome section. In the paper, the dome thickness of an arbitrary composite pressure vessel was forecasted by the cubic spline function and compared with the existing methods and actual measured values. The results show that the cubic spline function is more realistic than the other methods. Then the FEA considering the dome thickness pre-calculated by various methods was performed and compared with experimental data. The results further indicate that the cubic spline function could provide a more accurate model, which is approaching the real case.
Numerical Simulation on Damage and Failure in 3-Dimensional Braided Composites Structure against Bird Strike
Authors: Xitao Zheng , GuangLiang Li , ZeJiang Li , Qiang Yang
Published: September 2018

This paper describes the numerical simulation of bird strike damage response of 3-D (three-dimensional) braided I-shaped beam composite structures. The finite element model of a windshield structure including keel, glass, frame-work and rubber was established, in which the proper boundary condition was defined. The model contained five types of braiding modes. Three kinds of thickness (10 mm, 15 mm and 20 mm), and all of these models were impacted by three different velocities (80 m/s, 150 m/s and 200 m/s) respectively. The commercial FE package PAM-CRASH was used to analyse and the results including the damage, displacement and strain of the windshield were obtained, which are consistent with experimental observations.
The Numerical Simulation Research of Internal Curing Process for Fiber Winding Composite Shell
Authors: Xu Jiazhong , Wang Xinying , Qiao Ming , Yu Ying
Published: September 2018

Curing process has a great impact on molding quality of the fiber-winding composite shell. In order to improve its curing quality and efficiency, a new curing process employed the method of heating the internal metal mandrel with steam can be adopted, which is called internal curing process. This paper introduces the principle of internal curing process and establishes the mathematical models of internal curing process, adopts ANSYS and APDL to develop the 3-D transient numerical simulation program of internal curing to realize numerical simulation of temperature, curing degree and residual strain, and analyze the influence of shell thick, fiber volume fraction and film coefficient on the simulation results. Taking the cylinder shell as an example, numerical simulation and experiment are carried out. This research provides theory basis and analysis method for the design, simulation and parameter optimization of internal curing process.
A Homogenized Method Including Strain Gradients Based FFT Prediction of the Mechanical Properties of Composites
Authors: Tian Xiaoxiao , Li J. , Meng Songhe , Xu Chenghai , Wei Liming
Published: September 2018

This paper presents a unified method to predict the effective properties of the composite materials with periodic microstructure. First, based on the energy analysis, we use the multiple scale asymptotic analysis for a periodic unit cell to achieve a series of differential equations. Those equations include the first-order and the second-order strain gradient constitutive equations besides the conventional homogenized constitutive equations. Second, we further show that these equations can be converted into solving unified formal differential equations. Finally, we give the numerical method based upon Fast Fourier Transforms and taking the strain gradients into account and the solution is based on the explicit form of the periodic Green's function of the reference medium. This method is different from classically investigated by the Finite Element Method which need meshing.
The Improvement of Wettability, Mechanical and Thermo-mechanical Performances of PBO Fiber/Epoxy Composites by Adding Reactive Carbon Nanotubes
Authors: Li Xiaochao , Sui Gang , Yang Xiaoping , Yu Yunhua , Shi Lingfei
Published: September 2018

A kind of reactive multi-walled carbon nanotubes (r-MWNTs) was prepared and incorporated in an epoxy matrix. Then the epoxy matrix containing 0.5 wt.% r-MWNTs was reinforced by poly-p-phenylene benzobisthiazole (PBO) fibers and the NOL-rings were prepared on a filament winding machine. The wettability of the uncured epoxy was evaluated by measuring the surface energy and viscosity. It was demonstrated that the epoxy with r-MWNTs exhibited much better wettability than that of pristine epoxy. After adding 0.5 wt.% r-MWNTs, the tensile strength, tensile modulus, elongation and interlaminar shear strength (ILSS) of NOL-rings demonstrated an enhancement of 11.02%, 1.86%, 16.52% and 61.1%, respectively, compared to the pristine epoxy composites. In addition, scanning electron microscopy (SEM) studies revealed that the addition of r-MWNTs could significantly improve the interfaces bonding between PBO fiber and epoxy matrix. The dynamic mechanical analysis results also showed that the glass transition temperature of the composites increased by about 5 °C after the addition of 0.5 wt.% r-MWNTs.
Finite Element Analysis of Controlled Drug Release Based on Biphasic Model of Hydrogel Carrier
Authors: Zhanga Yanyan , Jia Yuxi
Published: September 2018

Over the past few decades, many efforts have been made in the research of controlled drug release systems, which is an effective way to solve the problem of poor curative effect. Due to their excellent biocompatibility, hydrogels have a wide application as promising drug carrier materials in pharmaceutical domain. In this paper, a new mathematical model was established based on the multiphasic theory of hydrogels, and a commercial finite element solver was adopted to implement the simulation of drug release from a swollen hydrogel. Simulated results show that the swelling of the hydrogel carrier begins from the edge to the center, and the drug release is initially anomalous transport followed by Fickian diffusion when the swelling of the hydrogel approaches to a new equilibrium state.
Tuning the Emission Color of Conjugated Polymers via Oxidation Copolymerization of Fluorene and 3,4-Ethylenedioxythiophene
Authors: Ouyang Mi , Xiang Wen-qin , Xu Yi , Zhang Yu-jian , Qian-pingLou  , Zhang Cheng
Published: September 2018

In this paper, 3,4-ethylenedioxythiophene (EDOT)units are introduced to polyfluorene via chemical oxidation polymerization. FTIR and 1H NMR spectra results confirm that the products are copolymers. Elemental analysis results show that the EDOT content in obtained copolymers increases as the feed ratio of EDOT/fluorene increases. UV-vis and PL spectra results show that the wavelengths of absorption peaks and emission peaks present obviously red-shift with the increase of EDOT content (Figure 2). In addition, the emission colors of resulting copolymers could be tailored between blue and green via changing the feed ratio of 9,9′-dibutylfluorene (DBF)/EDOT.
Variation of Electro-Conductive Property of SSF/PA6 System under Impact Loading using a Modified SHPB
Authors: Lei Jin-tao , Chen Jian-kang , Zhang Ming-hua
Published: September 2018

In order to detect the variation of electro-conductive property of short steel fiber (SSF) filled polyamide-6 (PA6) under impact loading, a modified split Hopkinson pressure bar (M-SHPB) is suggested. Such M-SHPB is constructed by designing a new test electrocircuit, and connecting it to the specimen and oscillograph. On the other hand, a copper foil cover is designed and placed on the whole SHPB equipment for avoiding interference of electromagnetic wave existing in the testing environment. By means of M-SHPB, the relation between the resistance and dynamic stress or dynamic strain is effectively detected. The experimental results indicate that the resistance of the material decreases with the increase of strain or stress. The sensitive variation of the resistance appears at the beginning of the deformation of the material.
Effect of Nano-CaCO3 on Properties of PP/TLCP/CaCO3in-situ Hybrid Materials
Authors: Jiangtao Cai , Anning Zhou , Wenying Zhou
Published: September 2018

In this thesis, to reinforce and soften PP plastics, thermotropic liquid crystalline polymer (TLCP) and nano-CaCO3 were used. The PP/TLCP/CaCO3 in-situ hybrid materials were prepared in a twin-screw extruder respectively by one-step and two-step method. The effect of nano-CaCO3 adding method on PP/TLCP/CaCO3 in-situ hybrid materials was investigated. Polarization optical microscope (POM) and differential scanning calorimeter (DSC) measurements showed that: nano-CaCO3 play an important role in PP/TLCP system heterogeneous nucleation, and CaCO3 particles can increase the crystal growth rate of PP matrix more than the contribution of the improvement of crystallinity. Field emission scanning electron microscope (FESEM) observation revealed that the nano-CaCO3 enriched in the PP matrix though one-step method, which helped to promote the TLCP forming fibrils, therefore the tensile strength of one-step preparation sample was higher relatively. Mechanical measurements revealed that under the condition of the same proportion of PP/TLCP/CaCO3/PP-g-MAH=85/5/4/6, the mechanical properties of the hybrid materials prepared by one-step method were better than which of two-step method, the tensile strength of the one-step sample was 36.62 MPa, increased 2.95% more than which of two-step sample, the elongation at break of one-step method sample was 35.12%, increased 76.4%: the impact strength was 3.86 kJ/m2, and increased 4.9%.
A Rapid Design and Design Knowledge Management System for Mould of Autoclave Forming Resin Matrix Composite Components
Authors: Bi Feng-yang , Jin Tian-guo , Peng Gao-liang , Liu Wen-jian
Published: September 2018

Autoclave forming is an important method for manufacturing matrix composite components with large dimension and high quality. Digitization of its manufacturing process is an active research field. The quality of manufacturing process information representation has great impact on the reuse of knowledge. Therefore, based on the analysis of devices, processing parameters and mould structure requirement in autoclave forming, an ontology-based representation for matrix composite components manufacturing process is presented. It can digitally describe and store device capability parameters, process parameters, and mould structure parameters. Thus a knowledge framework for mould design of autoclave forming is presented, and on that basis a rapid design prototype system for mould is developed, in it a mould design process wizard is built to integrate the mould design process, it include input information, calculation, analysis, data storage, display the result of mould design. The outcome of this system can be used for knowledge for autoclave forming mould design storage and reuse.
Preparation of Poly(vinylidene Fluoride)/P123 Blend Microporous Membranes via Thermally Induced Phase Separation Process
Authors: Cui Zhen Yu
Published: September 2018

The thermally induced phase separation (TIPS) process was employed to prepare poly(vinylidene fluoride)/polyethylene oxide-co-polypropylene oxide-co- polyethylene oxide (PVDF/PEO-PPO-PEO, or PVDF/P123) blend microporous membranes using sulfolane as the diluent. The effect of P123 content on the phase diagram of the PVDF/P123/sulfolane system was analyzed. The effects of P123 weight fraction and cooling rate on the cross-sectional morphology, crystallinity, crystal structure, thermal stability and porous structure of the resulting membranes were investigated using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and mercury porosimetry, respectively. The mechanical properties of the membranes were evaluated by tensile tests. It was found that solid-liquid phase separation occurred in the PVDF/P123/sulfolane system. The addition of P123 decreased the dynamic crystallization temperature of the PVDF/P123/sulfolane system. SEM revealed that neither increasing the P123 weight fraction nor decreasing the cooling rate would lead to macroscopic phase separation between P123 and PVDF. P123 weight fraction and cooling rate had some influence on the crystallinity, porous structure and mechanical properties, but no influence on the polymer crystal structure of the membranes. P123 weight fraction influenced the thermal stability of the final membranes but the cooling rate did not. The influences of the change in morphology, crystallinity, etc on the property of membranes for lithium ion battery, such as ionic conductivity, were also investigated.
Preparation and Characterization of Nanofiltration Membranes Synthesized by Hyperbranched Polyester and Terephthaloyl Chloride (TPC)
Authors: Wei Xiu-Zhen , Yang Jia , Zhang Guo-Liang
Published: September 2018

Thin-film composite (TFC) nanofiltration (NF) membranes were developed by terephthaloyl chloride (TPC) crosslinked the hydroxyl ended groups of hyperbranched polyester (HPE) on polyacrylonitrile (PAN) support. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) indicated that a thin layer of crosslinked HPE molecules were deposited on PAN porous membrane surface successfully. The preparation conditions were also optimized. The separation performance of PAN-HPE-TPC NF membranes are mainly related with the concentration of monomer in the aqueous phase rather than that in the organic phase. Water permeability and salts rejections of the membranes were measured. The flux and rejection of these NF membranes for Na2SO4 (1 g/L) reached 11.43 L/m2h and 96.5% under 0.6 MPa, respectively. At the same time, the nanofiltration properties were compared with other membranes prepared with hyperbranched polymers. All NF membranes prepared with hyperbranched polymers showed relative high permeate flux.
Morphology and Gas Permeability of Polymeric Membrane by PC/PA6/Nanoclay Ternary Nanocomposite
Authors: Gholizadeh B. , Arefazar A. , Barzin J.
Published: September 2018

In this study, polymer membranes were prepared by the melt processing, based on a polycarbonate (PC)/polyamide (PA6) blend, using PC as the matrix phase and PA6 as the dispersed phase. Moreover, nanocomposite membranes were also prepared by the melt processing on the basis of a PC/PA6/nanoclay blend. The permeability of polymeric membranes was calculated using theoretical models. On the other hand, the permeability of PC/PA6/nanoclay nanocomposite membranes was measured by an isochoric method. Then the results were compared. The cross-sectional morphology of the prepared membranes was observed by SEM. The surface roughness of the samples was measured by AFM. Results showed that the levels of porosity and surface roughness of membranes decreased with increase in PA6 concentration. According to the results, an increase in permeability is observed, with increase in PA6 concentration, and PC/PA6 benefit blend for prepared membrane to increase selectivity and performance. With the addition of nanoclay to the blend, the degree of porosity and the free volume decreased, and the roughness in membrane also decreased; in fact, a decrease in permeability is observed when nanoclays are added.
Comparison of Polyimide Composites with Non-covalent Modified and Acid Modified Multi-wall Carbon Nanotube
Authors: Chou Shang-Chih , Cheng Yao-Yi
Published: September 2018

In this study, it was attempted to increase the electrical conductivity of polyimide (PI) by adding multi-wall carbon nanotubes (MWNT), mainly because the high aspect ratio carbon nanotubes can reduce resistance and enhance antistatic ability to meet electrostatic charge (ESC) criteria of polymer hybrid films. MWNT were modified successfully with a sodium salt of 6-aminohexanoic acid (Na-AHA), which has been verified by FTIR and TEM observations. During the blending process, the PI/MWNT composites thus produced were compared with unmodified MWNT to study the miscibility and interaction among the components. The homogeneous dispersion of the non-covalently modified MWNT (Na-AHA-CNT) promoted the thermal and electrical conductivity properties of PI composite films. The results are compared with those of PI composites with acid-modified and unmodified MWNT.
Effect of the Extrusion Process on the Morphology and Electrical Conductivity of Injection-Moulded Polypropylene/HDPE/Carbon Black Composites
Authors: Liu Zheng-Ying , Gao Yong-Juan , Yin Chao-Lu , Huang Shi-Lin , Yang Ming-Bo
Published: September 2018

In this work, isotactic polypropylene (iPP)/high density polyethylene (HDPE) composites filled with carbon black (CB) were prepared by the mild compounding method and the common melt-mixing method. The selective distribution of CB particles in the immiscible iPP/PE blends was determined by the interfacial tensions, but the morphologies of the polyblends strongly depended on the compounding method. The mild compounding method strongly affected PE phases to form triple phase morphology in the composites, which inhibited effective conductivity network formation in the low CB content range. A skin-core structure of the iPP/HDPE/CB composite, prepared by the common melt-mixing process, was present when an effective conductivity network was obtained, and a co-continuous structure of the iPP/HDPE matrix is not necessary.
Tensile Properties of Polymer Samples Containing Millimetre Scale Silicon Microchips
Authors: Kolonko A.M. , Metje N. , Chapman D.N. , Kukureka S.N.
Published: September 2018

In order to produce monitoring systems for polyethylene pipes, one option is to distribute sensors within the plastic matrix. Currently, no information is available on the effects of small, individual sensors on the structural integrity of polyethylene pipes if these are embedded in the pipe wall. In order to assess the influence of these sensors, small samples were subjected to tensile tests with different sizes and shapes of microchips investigated at different positions and orientations. It was discovered that a square microchip improves the stiffness the most but reduces the ductility of the sample the most, while a microchip with the same area, but of circular shape also acts as reinforcement when its volume is sufficiently large relative to the volume of the polymer matrix, causing the smallest reduction in ductility. The optimal microchip orientation is parallel to the tension direction.
Study of Diffusion Performance and Preparation Technology of the Coloured PMIA Fibre
Authors: Liu Li-Qi , Chen Lei , Hu Zu-Ming , Yu Jun-Rong , Jing-Zhu
Published: September 2018

Poly(m-phenylene isophthalamide) (PMIA) fibre is a kind of aromatic polyamide fibre, which can be prepared by a wet-spinning method. In this work, the process conditions of spinning influenced the performance and structure of the coloured PMIA fibre, and these conditions included spinning speed, coagulation bath, etc. Because the diffusion coefficient was associated with the performance and structure, the ratio of solvent to coagulant could explain the reason of influence of the coagulation bath on the fibre. In this study, PMIA spinning dopes with Colour Inde Blue 60 were first commixed in a pressurizer and then spun into a coagulation bath under a pressure of around 0.3 MPa. At a coagulation bath temperature of 50 °C, pure or dope-dyed PMIA fibres were prepared by wet spinning, and then the spun fibres were extracted by an ultrasonic oscillation method. The effect of the jet stretch ratio and the temperature and concentration of coagulation bath on the ratio of diffusion coefficient of solvent to coagulator were analysed during spinning process of dope-dyed PMIA fibres. The properties and structures of coloured PMIA fibres were characterized by SEM. Finally the optimized spinning technology of the dope-dyed PMIA fibre was obtained.
The Structure and Nonisothermal Crystallization Kinetics of HDPE Nanocomposites Filled with Mg2Al–LDH
Authors: Qin Jun , Chen Xiaolang , Yu Jie , Xie Tian , Tian Yaozhu , Lv Qing , Xie Pu
Published: September 2018

High-density polyethylene (HDPE)/Mg2Al–layered double hydroxide (Mg2Al–LDH) nanocomposites with an ethylene-acrylic acid random copolymer (EAA)/Mg2Al–LDH master batch were prepared by melt-mixing. The structure of the nanocomposites was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results demonstrate the formation of the nanocomposites with exfoliated/intercalated layered double hydroxides well distributed in the HDPE matrix. The nonisothermal crystallization behaviour of master batch-based HDPE nanocomposites was studied by using differential scanning calorimetry (DSC). The crystallization behaviour of HDPE/Mg2Al–LDH nanocomposites was well defined by the Avrami analysis and Jeziorny method, as well as the combined Avrami and Ozawa analysis (MO's model). The results reveal that a very small amount of Mg2Al–LDH (1%) accelerates the crystallization process in comparison with the neat HDPE, and the high crystallization rate is attributed to the nucleating effect of the exfoliated nanoparticles. Overall, the exfoliated Mg2Al–LDH particles act as the nucleating agent, and therefore distinctly change the type of nucleation, growth and geometry of HDPE crystals.
Fibre Volume Fraction and Chamber Length Impact on Detached versus Attached Resin Injection Pultrusion
Authors: Palikhel D.R. , Roux J.A. , Jeswani A.L.
Published: September 2018

Resin injection pultrusion is an efficient and highly automated continuous process for high-quality, low-cost, high-volume manufacturing of composites. This research focuses on the impact of the fibre volume fraction and chamber length on resin injection pultrusion. Fibre volume fraction impact on the strength of the final composite is important since higher fibre volume fraction composites generally yield higher strength. Manufacturing composites with higher fibre volume fraction are more difficult because higher fibre volume fractions require higher injection pressures to achieve complete reinforcement wet out and thus yields higher maximum interior chamber wall pressures. In this work the impact of fibre volume fraction on complete wet out of reinforced fibre is investigated in the attached-die and detached-die resin injection pultrusion process with various resin injection chamber length considerations. This work explores the resin minimum injection pressure needed to achieve complete wet out, the corresponding maximum pressure inside the resin injection chamber so as to improve injection chamber design to keep the resin pressure within the injection chamber within reasonable constraints for different fibre volume fractions.
Study on Dielectric, Mechanical and Thermal Properties of Polypropylene (PP) Composites with Ground Tyre Rubber (GTR)
Authors: Mujal-Rosas R. , Orrit-Prat J. , Ramis-Juan X. , Marin-Genesca M. , Rahhali Ahmed
Published: September 2018

Mass production of tyres and their subsequent storage after use is a serious environmental problem whose solution has been attempted in various ways. One of these is the mixture of old, used tyres (GTR) with various thermoplastic and thermostable polymers. These blends are made by modifying the pre-treatment to which the GTR is subjected, the degree of devulcanization, the mixing or pressing conditions, etc. Later, the mixtures are analyzed structurally and mechanically, looking for possible industrial applications. The present work aims to obtain materials suitable for the electrical industry from the mixture of polypropylene (PP) with old used tyres (GTR), starting from the requirement of minimum recycling costs, i.e. by using vulcanized GTR without any prior treatment, but acting on the particle sizes with a simple and inexpensive screening. A large number of composites have been analyzed, and these have been submitted to dielectric, mechanical, thermal and microstructural examination. Composites were obtained using the three GTR particle sizes (p<200 μm, 200
500 μm), and the seven concentrations of GTR in the composite (0%, 5%, 10%, 20%, 40%, 50% and 70%), meaning a total of 21 new composites. In addition, in order to have the dielectric tests as exhaustive as possible and show the behaviour of the composite under widely changing conditions, a wide range of temperatures (30 °C to 120 °C) and frequencies (1·10-2 Hz and 3·106 Hz) were used. All these data have allowed an accurate characterization of the properties of the new composites, and according to these results, possible electrical applications have been explored, with the requirement that they must comply with Official Regulations.
Mechanical and Thermal Properties Analysis of Polypropylene Reinforced with Polyamide Microfibre Obtained from Shredded Tyres
Authors: Parres F. , Crespo-Amorós J.E. , Nadal-Gisbert A. , Navarro R.
Published: September 2018

The importance of recovering waste materials generated by industrialised societies is mainly due to the environmental impact that they have, and one of the principal problems is the presence of end of life tyres. The use of waste microfibre obtained from shredded tyres as reinforcement in polypropylene matrices offers an interesting opportunity for recycling of the waste microfibre, in order to obtain ‘value added products’ from polypropylene (PP)/waste microfibre tyre composites. The microfibres obtained from shredded tyres were used as a reinforcing material in compositions with polypropylene (PP). The blending proportions were: (1) 10% microfibre 90% PP; (2) 20% microfibre, 80% PP; (3) 30% microfibre, 70% PP; (4) 40% microfibre, 60% PP, (5) 50% microfibre, 50% PP and (6) 80% microfibre, 20% PP. The mechanical and thermal properties were analyzed. In this case polypropylene mixed with polyamide (PA) microfibres show a decrease in tensile strength and elongation at break, however, impact strength and Vicat Softening temperature values increase with polyamide microfibre content. Continuity in the matrix phase was observed by scanning electron microscopy up to loadings of 40% microfibre.
Effects of Plant Polyphenols on the Interface and Mechanical Properties of Rubber/Silica Composites
Authors: Xu Congsheng , Xu Guokai , Du Mingliang , Zhu Han , Fu Yaqin , Zhang Xianming
Published: September 2018

Based on the abundant surface hydroxyl groups of plant polyphenols and their tendency for complexation with metal ions, a facile and green approach to improve the interfacial interactions between silica and a rubber matrix is proposed. The interface interactions of plant phenols with silica and Zn ions are characterized by attenuated total refraction Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The results suggest that, with the introduction of plant phenols, strong interface interaction between rubber matrix and silica can be formed through hydrogen bonding and chelating effects. The investigation of mechanical performance of the composites indicates that the proposed approach produces remarkable reinforcing effects on the rubber matrix.
Event Segmentation Deficits in ADHD
Authors: Ryan Julia , Rogers Maria
Published: September 2018

Event segmentation is the automatic cognitive process of chunking ongoing information into meaningful events. Event segmentation theory (EST) proposes that event segmentation is a grouping process fundamental to normal, everyday perceptual processing, taking a central role in attention and action control. The neurocognitive deficits observed among individuals with ADHD overlap those involved in event segmentation, but to date no research has examined event segmentation in the context of ADHD. Objective: The goal of this study was to document the event segmentation deficits of individuals with ADHD. Method: Seventy-five undergraduates with ADHD and seventy-nine without ADHD performed an event segmentation task. Results: Results revealed that undergraduates with ADHD identify significantly more large events. Conclusion: These findingssuggest explicit disturbances in the event model and updating system among those with ADHD. Future research directions include further elucidating these deficits with more varied stimuli and establishing associations with functional impairments.
Macular edema after cataract surgery in eyes with and without pseudoexfoliation syndrome
Authors: Ilveskoski Lotta , Taipale Claudia , Holmström Emil J , Tuuminen Raimo
Published: September 2018

Background:

The purpose of the study was to identify macular edema after cataract surgery in eyes with and without pseudoexfoliation syndrome. The study was a post-hoc analysis of a randomized, double-blind, prospective single-center study. Patients were enrolled between January 2016 and October 2016 as per the national guidelines for the management of cataract in the Department of Ophthalmology, Kymenlaakso Central Hospital, Kotka, Finland.

Methods:

One hundred and fifty-six eyes of 149 patients undergoing routine cataract surgery. Postoperatively anti-inflammatory medication was either dexamethasone (N = 78) or diclofenac (N = 78). Spectral domain optical coherence tomography imaging and laser flare meter measurement of the anterior chamber were conducted before surgery and at the control visit 28 days postoperatively.

Results:

Baseline variables were comparable between eyes with pseudoexfoliation syndrome (N = 32) and those without (N = 124), except for intraocular pressure ( P = 0.002) and glaucoma medication ( P < 0.001). In patients having pseudoexfoliation syndrome, central retinal thickness increase (mean ± standard error of the mean) was 63.3 ± 35.5 μm for dexamethasone and 17.6 ± 5.8 μm for diclofenac, compared to 28.9 ± 8.0 μm ( P = NS) and 6.9 ± 1.3 μm ( P = 0.014) in eyes without pseudoexfoliation syndrome, respectively. Aqueous flare at 28 days was 25.8 ± 5.4 pu/ms for patients with pseudoexfoliation syndrome and 18.3 ± 1.8 pu/ms for those without ( P = 0.030). Best corrected visual acuity gain and best corrected visual acuity at 28 days were less in patients having pseudoexfoliation syndrome compared to those without (0.39 ± 0.07 vs 0.59 ± 0.03 decimals, P = 0.007; and 0.77 ± 0.06 vs 0.92 ± 0.03 decimals, P = 0.008, respectively).

Conclusion:

Eyes with pseudoexfoliation syndrome may be predisposed to an increased aqueous flare and macular edema after cataract surgery. This study outlines the need to determine the optimal anti-inflammatory medication after cataract surgery in patients with pseudoexfoliation syndrome.
Valsalva retinopathy associated with intranasal cocaine abuse: A case report
Authors: Karasavvidou Evdoxia-Maria A , Athanasopoulos Georgios P , Konstas Anastasios G , Tsirampidou Eleni A , Tranos Paris G
Published: September 2018

Introduction:

The purpose of this report is to describe a case of Valsalva retinopathy in an intranasal cocaine user.

Case report:

A 49-year-old male presented with a history of sudden loss of vision and inferior visual field defect in his left eye. Clinical evaluation of the affected eye showed best corrected visual acuity of 20/25 and fundus examination revealed a preretinal hemorrhage superior to the disk with multiple intraretinal hemorrhages in and around the posterior pole. On further questioning, the patient revealed intranasal cocaine use the day before the onset of his visual symptoms. Blood tests were requested to exclude blood dyscrasias or predisposition to vascular occlusive disorders and no further treatment measures were taken. The patient was reviewed a month later when his hemorrhages had completely resolved and his visual acuity had improved to 20/20. His blood results were within normal limits.

Conclusion:

Although never been reported before, Valsalva retinopathy can be associated with intranasal cocaine abuse and should be considered in the differential diagnosis of visual reduction in such population.
A new sporting horizon: a content analysis of Super Netball newspaper coverage
Authors: English Peter , Calder Angela , Pearce Simone , Kirby Katy
Published: September 2018

A new professional netball competition in 2017 was part of a long-awaited boost for women’s sport in Australia. Netball has a significant footprint across the country, being the nation’s largest female participation team sport, and the national team is the reigning world champion. However, the sport has traditionally been underrepresented in both sports media and academic research. The new league was scheduled on free-to-air television after a landmark broadcast deal and the rise in media coverage reflected the growing commercial and public interest in female sport. As an example of this changing environment, it is important to examine what the coverage of women’s netball involves. This descriptive study utilises a content analysis to explore the newspaper sports reporting of the first season of the Super Netball League. Specifically, it measures the amount and tone of coverage, the types of stories and descriptions employed in articles, including mentions of men’s sport. Data have been collected from 703 articles from 15,335 stories in newspaper sports sections of nine national, metropolitan and regional publications. While newspaper coverage of netball was comparable with other sports in terms of professionalism and content, there was still only a small amount of stories.
Meaning-making and crime drama: the case of criminology students
Authors: Wimshurst Kerry
Published: September 2018

Criminology as a discipline maintains an ambivalent attitude towards mass media. Following from Clifford and White’s call for a more nuanced approach to media criminology, the first section of the article contextualises the present study by outlining the uneasy relationship between mainstream criminology and crime drama. The second section explores themes that arose during research that invited criminal justice students to create an outline for a television crime series that they would enjoy watching themselves. The experience of creating and talking about their crime fictions prompted the participants to reflect on aspects of their own lives in some detail, but relatively little on crime per se. Crime drama, including their own creations, provided the participants with an anchor to talk broadly about subjectivities and identities. The piece concludes with observations on the place of emotional engagement when consumers reflect on crime drama.
The virtuous cycle of news sharing on Facebook: Effects of platform affordances and journalistic routines on news sharing
Authors: dos Santos Marcelo Alves , Lycarião Diógenes , de Aquino Jakson A
Published: September 2018

A growing body of literature shows how important content is in terms of news sharing. Nevertheless, the same literature overlooks the theory and corresponding effects on audience metrics produced by news routines adapted to platform affordances. This article aims to contribute to closing this gap by investigating 99 Facebook news pages covering 13 countries ( n posts = 823,184). Causality tests demonstrate that a combination of posting regularity, the use of native video and balance of posting may lead to a virtuous cycle of news sharing. Since this is not a trivial endeavour, we conclude that success of news media requires strategic planning of news routines to make them suitable to each platform. In terms of implications for future research, the accumulated knowledge on news sharing should be reassessed since our data show that the same content has greater chances of being shared according to the variables investigated in this research.
Study-related exhaustion: First-year students’ use of self-regulation of learning and peer learning and perceived value of peer support
Authors: Räisänen Milla , Postareff Liisa , Mattsson Markus , Lindblom-Ylänne Sari
Published: September 2018

This study examines the profiles of self-regulation of learning, peer learning and peer support among students. The study investigates whether the profiles differ in terms of reported study-related exhaustion. Students completed a questionnaire regarding their use of self-regulation of learning and peer learning and perceived peer support and study-related exhaustion. Four different student profiles were found. The profiles differed in terms of self-reported study-related exhaustion. Self-regulated students with a low level of peer learning and low perceived value of peer support reported the lowest levels of study-related exhaustion, whereas students with self-regulation problems, a high level of peer learning and high perceived value of peer support reported the highest levels of study-related exhaustion. The results showed that problems in self-regulation were positively related to self-reported study-related exhaustion. Identifying different student profiles helps to recognise students who may need more support in studying.
Validation of a procedure for the evaluation of the performance of an installed structural health monitoring system
Authors: Heinlein Sebastian , Cawley Peter , Vogt Thomas
Published: September 2018

Validation of the performance of guided wave structural health monitoring systems is vital if they are to be widely deployed; testing the damage detection ability of a system by introducing different types of damage at varying locations is very costly and cannot be performed on a system in operation. Estimating the damage detection ability of a system solely by numerical simulations is not possible as complex environmental effects cannot be accounted for. In this study, a methodology was tested and verified that uses finite element simulations to superimpose defect signals onto measurements collected from a defect-free structure. These signals are acquired from the structure of interest under varying environmental and operational conditions for an initial monitoring period. Measurements collected in a previous blind trial of an L-shaped pipe section, onto which a number of corrosion-like defects were introduced, were utilised during this investigation. The growth of three of these defects was replicated using finite element analysis and the simulated reflections were superimposed onto signals collected on the defect-free test pipe. The signal changes and limits of reliable detection predicted from the synthetic defect reflections superimposed on the measurements from the undamaged complex structure agreed well with the changes due to real damage measured on the same structure. This methodology is of great value for any structural health monitoring system as it allows for the minimum detectable defect size to be estimated for specific geometries and damage locations in a quick and efficient manner without the need for multiple test structures while accounting for environmental variations.
Blends of Natural Rubber and Hydrogenated Nitrile Rubber Containing Dichlorocarbene Modified Natural Rubber. Part I - Aging Behavior
Authors: Elizabeth K.I , Alex Rosamma , Kuriakose Baby
Published: September 2018

Hydrogenated nitrile rubber (HNBR) could be blended with natural rubber (NR) to improve its oil and aging resistance without affecting drastically the dynamic properties. The polarity difference between the polymers is reduced by incorporation of small quantities of dichlorocarbene modified NR (DCNR) which is formed during the alkaline hydrolysis of chloroform in presence of NR. The enhancement in technical properties in presence of DCNR is due to its dipole interaction with the –CN group of the acrylonitrile segments in HNBR as revealed from a shift in the characteristic IR absorption peak. Thus modified form of NR enables the formation of a more uniformly mixed blend of NR and HNBR resulting in more cross links as revealed from an increase in rheometric torque. In blends, the NR matrix cross links to a same extent as pure NR, while the level of crosslinking of HNBR matrix is lower than that obtained for the pure HNBR. However in the presence of DCNR there is the formation of interfacial crosslinks as evaluated from selective solvent swelling. During aging at a comparatively lower temperature the NR matrix of the blend undergoes crosslinking reactions while at high temperatures it undergoes scission reactions. The scission reactions taking place in the NR matrix are reduced in presence of DCNR as observed from the application of two-network theory for samples subjected to high temperature stress relaxation. A reduction in chain scission reactions at high temperature results in better aging characteristics of the modified blends.
In-Mould Painting by Spraying Thermoset Powder Coating into a Closed Mould, Followed by Standard Thermoplastic Injection Moulding: Part 1: Introducing the IN-SPIRE Process
Authors: Goodship V. , Lobjoit C. , Cook N. , Smith G.F.
Published: September 2018

Injection moulding technologies are constantly evolving to meet changing customer requirements, improved cost effectiveness and to meet new environmental legislation. One such technology is in-mould decoration (IMD). This technique is attractive due to increased customer desire for multi-functional and decorative products and includes any process in which a fully, or partially, decorated component is produced directly from the moulding process.

A new patented IMD process has been developed to produce a painted component direct from the injection moulding tool. It uses thermoset powder coatings which are sprayed under pressure through a valve into a closed mould using a novel feed system. The heat of the tool softens the coatings which are then cured by the injection of thermoplastic polymer into a standard injection moulding system. In this first paper initial design features and considerations as well as the process itself are discussed.
Influence of Carbonized Rubber Seed Shell as Filler on Vulcanisates from Blends of Natural Rubber and Epoxidized Low Molecular Weight Natural Rubber
Authors: Akinlabi A.K.
Published: September 2018

Studies into the use of carbonized rubber seed shell as a filler in formulations for blends of natural rubber (NR) and epoxidized low molecular weight natural rubber (ELMWNR) prepared using the semi-efficient sulphur vulcanisation system were carried out. The rheological properties (cure rate, cure time, t90 and scorch time, t2), physico-mechanical properties, solvent resistance, solubility and swelling properties of the vulcanisates showed carbonized rubber seed shell behaving as a plasticizer/softener in the mix. From the properties investigated, replacement of carbon black with 15% carbonized rubber seed shell will not make any serious deleterious effect on the vulcanisate, also carbonized rubber seed shell can be used as a filler in products where softness is anticipated. Above all, the properties obtained from the carbonized rubber seed shell vulcanisates are within the accepted level for natural rubber mix.
Effect of Alkali treatment on the Mechanical Properties of Short Randomly Oriented Isora Fibre-Polyester Composites
Authors: Joshy M. K. , Mathew Lovely , Joseph Rani
Published: September 2018

This paper reports the effect of alkali treatment on the mechanical properties of the natural fibre “isora” as reinforcement in unsaturated polyester resin. Isora fibre is separated from the bark of Helicteres isora plant by retting process. Properties like tensile strength, flexural strength and impact strength have been studied as a function of duration of alkali treatment and concentration of alkali. Alkalization of the fibre improves the mechanical properties of the composite. Tensile and flexural properties of the composite were found to be maximum and impact strength minimum, for an alkali treatment time of 4 hours. The mechanical properties were found to be optimum for an alkali concentration of 1%. The effects of alkali treatment on the fibre properties were investigated by SEM and IR. SEM studies were carried out to investigate the fibre surface morphology, fibre pull-out and fibre-polyester interface bonding. SEM gave evidence for the changes occurred on the fibre surface during chemical treatment.