bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Process Variables on the Tensile Properties of Fibreglass Nonwoven Composites
Authors: Yousfani Sheraz Hussain Siddique , Gong R.H. , Porat I.
Published: September 2018

Fibreglass nonwoven composites are a new class of fibre-reinforced composites, and in this work composite samples were manufactured by using nonwoven webs as reinforcement and thermo-setting resin as matrix. The samples were prepared by using a resin infusion technique, and the nonwoven webs were manufactured by a wet-laying method.

In this research work, the main purpose was to investigate the effects of different process variables, i.e. dispersion, fibre length and multiple layering, on the tensile properties of these composites. It was found that the tensile strength was improved by better dispersion of fibre strands. Tensile strength and stiffness of the composite samples were also improved by an increase in fibre length and by multiple layering.
Tightening Characteristics Research of M1.4 Subminiature Screw by Applying CFRP Laminates
Authors: Kim Dae-Young , Kim Jung-Ho , Ra Seung-Woo , Jeong Joung-An , Kim Ji-Hoon
Published: September 2018

The recent core technologies developed in automobile and aerospace industries can be classified into two types, namely, advancement technology for safety and convenience and mechanical technology for eco-friendly and lightweight systems. Research in the field of composite materials has attracted significant attention. Carbon-fiber-reinforced plastics (CFRP) show high specific stiffness and specific strength compared with metallic materials. They exhibit mechanical properties with high damping characteristics and are lightweight. However, according to the direction of a laminate or its stacking sequence, the structural characteristics of CFRPs vary. It is hard to predict fracture under tensile and bending forces in CRFPs, when compared to metals. Threaded fasteners with easy assembly and disassembly are used widely in several fields. However, to maintain clamping force, proper torque force should be applied. As the size of the components decreases, the clamping force also decreases because the contact area between the component and other components decreases. In this study, CFRP specimens were subjected to tensile tests via a universal testing machine to estimate their mechanical properties with respect to the stacking angles of the laminates. The reverse screw torque and screw torque at each stacking angle were determined using a torque tester after tapping holes on the CFRP specimens. It was expected that both the epoxy attached to the screw surface and stacking direction of CFRP laminates affect the screw torque force of the composite material. In the case of woven composite specimens, there was no difference observed even when torque was applied to prevent loosening of the specimens with or without coating. The average results for the woven composite specimens were better than that for the other specimens.
Enhancing the Corrosion Inhibition Behaviour of Epoxidized Natural Rubber-Polyaniline Dodecylbenzenesulfonate Blend via the Incorporation of WO3
Authors: Yong K.C.
Published: September 2018

Electrically-conductive (in the region of 10−3 S.cm−1) epoxidized natural rubber-polyaniline dodecylbenzenesulfonate [ENR-PAni.DBSA] blend was prepared, and the effect of incorporation of WO3 on its corrosion inhibition behaviour for carbon steel was assessed for the first time. It was found that the electrical conductivity of this blend could be enhanced by up to an order of magnitude for WO3 loadings of 20.0–22.5 wt.%. From both total immersion and electrochemical corrosion tests, ENR-PAni.DBSA blends with 20.0–22.5 wt.% of WO3 were found to be the best corrosion inhibitors for carbon steel, in both acid and artificial brine environments. However, a blend containing a higher WO3 content (i.e. 25.0 wt.%) showed a significant poorer corrosion inhibition behaviour for carbon steel due to its more severe phase separation and porosity between the ENR host matrix and WO3.
Comparative Study of High Performance Polymers in Selective Inhibition Sintering Process through Finite Element Analysis
Authors: Aravind A. , Siddiqui T.N. , Arunkumar P. , Balasubramanian E.
Published: September 2018

Selective Inhibition Sintering (SIS) is a novel additive manufacturing process which uses indigenously available polymers and the high cost laser system is avoided that makes the system cost-effective. Finite Element Analysis (FEA) is carried out to evaluate the performance of SIS process. The effect of temperature on the polymer structure is examined through coupled field transient thermo-structural analysis of various high performance polymer particles such as Polysulfone (PSU), Polybenzimidazole (PBI), Polyimide (PI), Polyethersulfone (PES), Perfluoroalkoxy alkanes (PFA), Ethylene tetrafluoroethylene (ETFE) and KCl is used as the inhibitor material. The structured finite element mesh model is created and heat flux is applied in equivalent time intervals to study the transient characteristics. Simulation results are presented with displacement, temperature and thermal stress for each polymer materials and their characteristics performance is evaluated.
Mechanical Behaviour of Aluminium Alloy Reinforced with Sic/Fly Ash/Basalt Composite for Brake Rotor
Authors: Venkatachalam G. , Kumaravel A.
Published: September 2018

Gray cast iron is the most commonly used material in automobile brake rotors. It generates heat easily during braking which affects its mechanical properties and the Coefficient of friction varies depending on the type of material used for the brake rotor. Aluminium (Al) based metal matrix composite can be an efficient and effective braking material compared to cast iron and matrix alloy. In the present investigation, Al6082 composites were fabricated by stir casting method by varying weight percentage of reinforcements for Sample1 (Al 90% + SiC 10%), Sample 2 (Al 90% + SiC 5% + fly ash 5%) and Sample 3 (Al 90% + SiC 5% + basalt 5%). Chemical compositions, micro hardness, wear test and tensile test were performed to study the mechanical behavior of all the test specimens. The surface morphology was studied using microscopic inspection to indicate the distribution of reinforcement particles and bonding between the matrixes. Composites containing hard oxides (like SiC) are preferred for high wear resistance along with increased hardness and high temperature oxidation resistance. The result reveals that wear rates of the composite materials is lower than that of the matrix alloy and friction coefficient was minimum. Also, it improves the micro hardness and tensile strength. The addition of fly ash and basalt decreases the wear and it acquired density almost three times lower than that of gray cast iron. In this investigation, the alternate materials for automobile brake rotors with Al reinforced composites were studied.
Tribological Behavior of Short Sisal Fiber Reinforced Epoxy Composite
Authors: Maurya Hari Om , Jha Kanishka , Tyagi Y.K.
Published: September 2018

Environment is being polluted day by day due to intensive use of synthetic fiber as reinforcement for polymer composite. The researchers, engineers and scientists are showing their interest in natural fiber as reinforcement in place of synthetic fiber due to its green nature. In this work, short sisal fiber reinforced epoxy composites were manufactured by hand lay-up method at 30% wt. of fiber loading and fiber length used was 10 mm. The parameters taken were load, speed and sliding distance. Load was taken as 10, 15, 20, 25 and 30 N, Sliding speed as 1 m/s, 2 m/s and 3 m/s and Sliding distance as 1000 m, 2000 m and 3000 m. The wear properties (specific wear rate and coefficient of friction) of prepared composites are carried out. All tests are performed as per ASTM standard. On increasing the load, sliding velocity and sliding distance, the specific wear rate is found to increase whereas value of coefficient of friction decrease.
Experimental Investigation on Volume Fraction of Mechanical and Physical Properties of Flax and Bamboo Fibers Reinforced Hybrid Epoxy Composites
Authors: Sathish S. , Kumaresan K. , Prabhu L. , Vigneshkumar N.
Published: September 2018

The aim of this paper is to study the effect of volume fraction on mechanical and physical properties such as tensile, flexural, impact, interlaminar shear strength, void content and water absorption of flax and bamboo fibers reinforced hybrid epoxy composites. Flax and bamboo fibers reinforced epoxy resin matrix hybrid composites have been fabricated by compression molding techniques. The hybrid composites were fabricated with different volume fraction of fibers. SEM analysis on the hybrid composite materials was performed to analyze the bonding behavior of materials and internal structure of the fractured surfaces. The effect of chemical treatment of flax and bamboo fibers was verified by FTIR analysis. The results showed that the tensile, impact, flexural and ILSS are maximum for 40:0 (flax: bamboo) hybrid composites. The void content decreased for 20:20 (flax:bamboo) composites due to tightly packed flax fiber and more compatibility towards epoxy resin.
Thermal Stability of Optically Transparent Alpha-Zirconium Phosphate/Poly(methyl methacrylate) Nanocomposites with High Particle Loading
Authors: Hatanaka Logan C. , Diaz Agustin , Wang Qingsheng , Cheng Zhengdong , Mannan M. Sam
Published: September 2018

Polymeric nanocomposites have gained attention over the past few decades for their enhanced thermal stability and degradation. However, the reactions involved in a polymer nanocomposite can vary significantly from system to system, making it necessary to investigate novel nanofillers in search for more effective materials. Nanocomposites comprised of alpha-zirconium phosphate (ZrP) nanosheets in poly (methyl methacrylate) (PMMA) were prepared with a wide range of nanoparticle loadings (0, 5, 10, and 30 wt.% ZrP in PMMA). The ZrP nanocomposites were characterized using UV-visible spectroscopy (UV-vis), x-ray diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Nanocomposites were well dispersed and optically transparent as shown by XRD and UV-vis. However in the UV region, transparent ZrP nanocomposites possessed excellent UV scattering properties, significantly reducing the transmittance of UV-light, while remaining transparent to the visual spectrum. Thermal stability studies using TGA and DTG showed the peak mass loss rate (PMLR) was reduced by 10% and simultaneously shifted to higher temperatures by 41 °C. Since the nanocomposites in this work cover such a large range of ZrP loadings, large amounts of high-temperature residuals were encountered after TGA studies, indicating that the high loading ZrP nanocomposites are largely noncombustible. In addition, DSC studies showed that ZrP content does affect the glass transition temperature, but not enough to limit the application in which ZrP nanocomposites could be used. These results point to ZrP nanocomposites being useful as polymer replacements, behaving like polymers until the event of a fire, in which case they are largely noncombustible.
Effect of Rubber Content on Fatigue Crack Growth Rate under Mode I Loading
Authors: Imanaka Makoto , Asano Hiroshi
Published: September 2018

Rubber-modified adhesives have attracted particular interest recently, owing to their property of dramatically increasing the fracture toughness of adhesively-bonded joints. In many cases, these joints are exposed to cyclic loads, and hence an understanding of the fatigue mechanisms is of paramount importance. This study was conducted to characterize the rubber content-dependent behaviour of rubber-modified epoxy adhesive under cyclic loading. Fatigue crack growth rates under mode I loading were measured using adhesively-bonded double cantilever beam specimens with rubber contents of 0, 5 and 14 wt.%. As a result, in the Paris region, an increase in rubber content reduced the fatigue crack growth rate. Similarly to the Paris region, the fatigue threshold for 5 wt.% was greater than that for 0 wt.%; however, the fatigue threshold of joints with 14 wt.% rubber content was nearly equal to those with 5 wt.%.
Experimental Study of In-plane Mechanical Properties of Carbon Fibre Woven Composite at Different Strain Rates
Authors: Lu Jiahai , Zhu Ping , Ji Qinghui , Cheng Zhang
Published: September 2018

Carbon fibre woven composite has been increasingly employed in engineering applications undergoing complex loading conditions. For effective use of composite material in dynamic applications, it is essential to fully understand the mechanical behaviour of composite at different strain rates. In the present study, both in-plane tensile and compressive experiments loaded at 0 degree axial direction and 45 degree off-axial direction of a TC33 carbon fibre woven composite were investigated over the strain rate range from 0.001 to 1000 s−1. High strain rate tests were carried out using Split Hopkinson Pressure and Tensile Bar apparatus respectively. The results indicated that the in-plane mechanical properties and failure patterns were strain rate sensitive under both tensile and compressive loadings. The mechanical properties, failure patterns and strain rate effect also showed highly direction dependent and tension/compression asymmetric characteristic within the considered strain rate range. For higher strain rate sensitivity under compression than that under tension, the asymmetry of mechanical properties was less obvious with the increase of strain rate. Finally, two phenomenal models were proposed to quantitatively fit the relationship between strength property and strain rate.
Behaviour of Hybrid SiC/Jute Epoxy Composites Manufactured by Vacuum Assisted Resin Infusion
Authors: Ramadan Noha , Taha Iman , Hammouda Rawia , Abdellatif M.H.
Published: September 2018

Natural fibre-reinforced polymer composites are standing in the limelight of investigations due to their light weight and availability from natural and renewable resources. Improved mechanical and physical behaviour is targeted through hybridisation with other reinforcing elements. This study investigates the potential of adding silicon carbide particles at volume contents ranging between 2 and 8% to jute fabric-reinforced epoxy composite to produce such hybrid composites. In contrast to the commonly applied processing technique of hand layup used to produce natural fibre-reinforced laminates, the vacuum-assisted resin infusion method was applied in this study to produce high quality laminates. Samples were tested for their mechanical behaviour through tensile, flexural and impact tests. Scanning electron microscopy was further performed to analyse the modes of failure of the composites. Finally, erosion tests were conducted, by directly sanding the hybrid composite samples to evaluate their erosion wear resistance. Results indicated that the addition of particles had a significant effect on the tensile, flexural, impact and erosion wear behaviour of the composites under investigation. Hybrid composites reinforced with 4 vol.% SiC exhibited acceptable mechanical properties. The behaviour was found to deteriorate at SiC contents beyond 4 vol.%.
Pull Speed Influence on Fiber Compaction and Wetout in Tapered Resin Injection Pultrusion Manufacturing
Authors: Masuram N.B. , Roux J.A. , Jeswani A.L.
Published: September 2018

In the resin injection pultrusion process (RIP), liquid resin is injected into the tapered injection chamber through the injection slots to completely wetout continuously pulled fibers. As the resin penetrates through the fibers, the resin also pushes the fibers away from the wall towards the centerline, causing compaction of the fiber reinforcements. The fibers are squeezed together due to compaction, making resin penetration more difficult; thus at low resin injection pressures, the resin cannot effectively penetrate through the fibers to achieve complete wetout. However, if the resin injection pressure is too high, the fibers are squeezed together to such an extent that even greater injection pressure is necessary to wetout the compacted fibers. The design of the injection chamber significantly affects the minimum injection pressure required to wetout the fiber reinforcements. A tapered injection chamber is considered such that wetout occurs at lower injection pressures due to the taper angle of the injection chamber. In this study, the effect of fiber pull speed on the fiber reinforcement compaction and complete fiber wetout for a tapered injection chamber is investigated.
Effect of Sisal Fibre Hybridisation on Static and Dynamic Mechanical Properties of Corn/Sisal/Polylactide Composites
Authors: Luo Honglin , Ji Dehui , Xiong Guangyao , Xiong Lingling , Zhang Chuanyin , Zhu Yong , Wan Yizao
Published: September 2018

The relatively poor mechanical properties of corn fibre (CF) and its green composites have hindered its applications. In this work, sisal fibre (SF) was hybridised with CF to reinforce polylactide (PLA) composites (CF/SF/PLA). The static mechanical properties such as tensile, flexural and impact strengths and dynamic mechanical properties such as storage modulus (E’), damping behaviour (tan δ), glass transition temperature (Tg) of the hybrid composites were determined and, for the first time, hybrid effects on both static and dynamic mechanical properties were evaluated. It is found that the tensile, flexural, impact strengths, and E’ and tan δ peak height, as well as the hybrid effects change with hybrid ratio (SF:CF). It is demonstrated that a hybrid composite with desirable static and dynamic mechanical properties can be produced by optimising the fibre:hybrid ratio.
Auto-hybridization of Polyethylene/Maple Composites: The Effect of Fiber Size and Concentration
Authors: Rodriguez-Castellanos Wendy , Rodrigue Denis
Published: September 2018

This work investigated the effect of maple fiber size and content on the auto-hybridization of linear low density polyethylene (LLDPE) composites. The samples were compounded by twin-screw extrusion and molded by compression molding. Different fiber loadings (5 to 20% wt.), fiber sizes (0-425 microns) and size ratios (30/70, 50/50, 70/30 of short, medium, and long fibers) were used to prepare the auto-hybrid composites with 3% of coupling agent (maleated polyethylene). Micrographs and impact strength results showed that the fracture in auto-hybrid composites is mostly dependent on the longer fibers. At 10% wt. the optimum ratio was 30/70 of shorter/longer fibers, which improved tensile strength (20%), tensile modulus (20%), and impact strength (13%) compared with composites with a single fiber size. But at 20% wt., tensile modulus increased by 30% and torsion modulus by 40% above the rule of hybrid mixtures (RoHM) at a 70/30 ratio of shorter/longer fibers.
Effect of Carbon Nanotubes' Dimension on Microwave Absorption Property of Polyaniline Nanocomposites
Authors: Koh Yen Nee , Mokhtar Nurrafiqah , Wai Phang Sook
Published: September 2018

Hexanoic acid (HA) doped PAni nanocomposites which containing aniline (Ani) as monomer was synthesized via template free method. Dielectric (titanium dioxide, TiO2) and magnetic (different dimension of multiwall carbon nanotubes (MWNT)) materials have been added to improve the dielectric and magnetic behavior of the PAni nanocomposites. Fourier transform infrared (FTIR) spectrometer, ultraviolet-visible (UV-Vis) spectrometer and X-ray diffractometer (XRD) analysis confirmed the chemical structure of doped-PAni. Morphology study and thermal behavior of the PAni nanocomposites have been investigated by field emission scanning electron microscope (FESEM) and thermal gravimetric analyzer (TGA), respectively. PAni nanocomposites with longer length and bigger diameter of MWNT possess the highest conductivity (1.51 × 10−2 S/cm) compared with those shorter length and smaller diameter PAni nanocomposites. Microwave absorption study was investigated by microwave vector network analyzer (MVNA) from 0.5 to 18 GHz. Among all the PAni nanocomposites, PAni nanocomposites with MWNT (φ = 10–20 nm, l = 5–15 μm) possess a sharp and narrow peak with high absorption (RL = −58 dB) at 7 GHz. In this study, it is observed that PAni nanocomposites with longer length and smaller diameter exhibit the largest amount of entangled nanorods/nanotubes that will eventually enhance the heterogeneity of the nanocomposites. Thus, it significantly induces the space charge polarization along the PAni backbone and indicates the strongest microwave absorption.
High Oxygen Barrier Polyethylene Films
Authors: Ayuso Carmen Fernández , Agüero Alejandro Arribas , Hernández Jose A. Plaza , Santoyo Antonio Bódalo , Gómez Elisa Gómez
Published: September 2018

“Layer by layer” technology was used to create transparent, thin and high barrier polyethylene films to use in food packaging. These films were made by inserting successive layers of polyacrylamide and montmorillonite (Cloisite Na+, non-organic modification) grown onto a low density polyethylene (LDPE) film substrate submitted to corona treatment. Excellent oxygen permeability results were reached with only 9 bilayers, with a reduction of 99.92%, compared to the pure polyethylene. This allowed the oxygen barrier film to change from poor to high (3.66 cm3/m2·day), with a total thickness of 48 microns, due to the structure formed over the film to create a tortuous path for oxygen molecules. Optical properties were analysed, showing a ≥92% transparency in all samples. Thermal stability of polyethylene was slightly improved and this was attributed to nanoclays presence forming an insulating layer. The result of this research is a thin structured film which is a good candidate for common barrier films replacement in food packaging thanks to its high oxygen barrier capacity, optical transparency, microwaveability and recyclability.
Influence of the Type of Epoxy Resin and Concentration of Glycidylisobutyl-POSS in the Properties of Nanocomposites
Authors: Longhi Marielen , Zini Lucas Pandolphi , Kunst Sandra Raquel , Zattera Ademir José
Published: September 2018

Epoxy resin is one of the most used resins for obtaining composites and coatings. Its properties have been modified using many materials, mainly based on nanotechnology, such as clays and polyhedral oligomeric silsesquioxanes (POSS). POSS may increase thermal and mechanical resistance and hydrophobicity of the epoxy resin. This study aims at characterizing epoxy nanocomposites, using two distinct resins (DGEBA and DGEBF) and an addition of glycidylisobutyl-POSS in contents of 2.5% and 5% (w/w), through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). Samples showed an amorphous halo due to the epoxy resin and a characteristic peak of POSS. TGA results showed a greater residual mass in DGEBF systems due to its wider formation of crosslinks. FTIR spectra demonstrated a higher amplitude of the hydroxyl band in DGEBF 5% system, which may affect its hydrophilic behavior because of the molecular mobility and resin weight reduction. DMA results showed that DGEBA systems are more flexible than DGEBF.
Facile Fabrication of Nanoclay Reinforced Waterborne Organic Coatings for Corrosion Protection
Authors: Li Jing , Ma Yuan , Yang Jiayun , Li Yaya , dai Yigang , Yang Junhe
Published: September 2018

The reinforcement effect of nanoclay on the corrosion protection properties of waterborne thin organic coatings was studied. The coating matrix was a commercial formulation for galvalume steel substrates. Two kinds of clays (laponite RDS and optigel WH) were employed as the barrier reinforcement in the composite coatings. Both kinds of the clays were exfoliated into monolayers of silicate with disordered structures at a filler content of 2 wt.%. Facile exfoliation and effective dispersion of clay was achieved with the assistance of a titanate coupling agent. The corrosion protection properties of the composite coatings were significantly improved with the addition of 3 wt.% laponite RDS or 2 wt.% optigel WH. The addition of an excessive amount of clay decreased the anticorrosion properties of the composite coatings. The fabrication methods of nanoclay-reinforced thin organic coatings involved only physical blending and latex mixing at ambient temperature, which can be easily scaled-up for mass production.
Adsorption of Dyes onto Sodium Alginate Graft Poly(Acrylic Acid-co-2-Acrylamide-2-Methyl Propane Sulfonic Acid)/ Kaolin Hydrogel Composite
Authors: Zhu Linhui , Guan Chengdong , Zhou Bin , Zhang Zhentao , Yang Rui , Tang Yaoji , Yang Jing
Published: September 2018

Adsorption of four dyes, namely methyl violet (MV), rhodamine 6G (R6G), acid chrome blue K (AK) and xylenol orange (XO) onto sodium alginate graft poly(acrylic acid-co-2-acrylamide-2-methyl-1-propanesulfonicacid)/kaolin (SA-g-P(AA-co-AMPS)/KL) hydrogel composite is studied. The factors influencing the adsorption capacities, including the initial concentrations of dye solutions, contact time, initial pH values and dosage of the adsorbent as well as ionic strength of the solution are discussed. It is more effective for the composite to adsorb cationic dyes such as MV and R6G rather than anionic dyes AK and XO. The maximum adsorption capacities of MV, R6G, AK and XO are 1361.1, 1627.8, 563.5 and 312.4 mg/g, respectively. The adsorption thermodynamics for the four dyes are in accordance with both the Freudlich and Redlich-Peterson equations. It is shown that adsorption of the cationic dyes R6G and MV is spontaneous, while that of anionic dyes AK and XO is not. The kinetics studies show that the adsorption of the four dyes fitted a pseudo-second-order equation.
Synthesis and Properties of Novel Thiophene-Based Liquid Crystalline Conducting Polymers
Authors: Roudini Danesh
Published: September 2018

Side-chain liquid crystalline polythiophenes were synthesised and the effects of the mesogenic units on the structure and electronic properties of the polymers were studied. The liquid crystal properties of the polymer films were studied using polarised hot-stage optical microscopy and differential scanning calorimetry, and X-ray diffractometry was used to investigate the effect of a magnetic field on the monomers and polymers.
Temperature Affects the Hydroxyapatite Crystal Arrangement on Silk Fibroin Surfaces
Authors: Zou Rui , Zhou Qin , Liu Qida , Li Quanli , Chen Zhiqing , Niu Lin
Published: September 2018

A hydroxyapatite (HAP)/silk fibroin (SF) bone-like biomaterial was fabricated through a coprecipitation process using stepped temperatures. We evaluated the effect of increasing temperatures on hydroxyapatite crystal arrangement on a silk fibroin surface. We found that the HAP crystal particles self-assembled on the silk fibroin surface. Further we found that with rising temperature the HAP crystal c-axis became progressively more parallel to the long axis of the silk fibroin. This deposition pattern is similar to that seen with HAP and collagen assembly in normal bone. Based on the XRD, SEM, and TEM results, we conclude that higher temperatures promote crystal nucleation resulting in an increase in both HAP crystal size and HAP/SF particle size. These data support the use of HAP/SF bone-like biomaterials for bone replacement and regeneration.
A Study of Cutting Temperatures in Turning Carbon-Fiber-Reinforced-Plastic (CRFP) Composites with Nose Radius Worn Tools
Authors: Chang Chung-Shin
Published: September 2018

Nine kinds of carbide nose radius worn tools were used in turning of high-strength carbon-fiber-reinforced-plastics (CFRP) materials to study the cutting temperature of tip's surface. A new cutting temperature model using the variations of shear and friction plane areas occurring in tool nose wear situations are presented in this paper. The frictional forces and heat generated in the cutting process are calculated by using the measured cutting forces and the theoretical cutting analysis. The heat partition factor between the tip and chip is solved by using the inverse heat transfer analysis, which utilizes temperature on the K type carbide tip's surface measured by infrared as the input. The tip's surface temperature is determined by finite element analysis (FEA) and compared with temperatures obtained from experimental measurements. Good agreement demonstrates the proposed model.
Mechanical Properties of Glass Bead-Modified Polymer Composite
Authors: Hsieh Tsung-Han , Shen Ming-Yuan , Huang Yau-Shian , He Qi-Qian , Chen Hsuan-Chih
Published: September 2018

This present work investigated the adhesive effect of the material properties and fracture toughness of a thermosetting epoxy polymer modified with micron-sized glass beads. Various surface treatments were used to modify the surfaces of the glass beads in order to consider the effect of the glass bead particle/epoxy adhesion on the material properties and toughness of the polymer-based composites. Adding glass beads into polymer resulted in an increase in the modulus. The maximum value of the modulus was obtained for the polymer composite modified with well-bonded glass beads. The addition of the glass beads to polymers leads to a significant improvement in the fracture toughness. The particle/matrix adhesion strongly affects the toughness of the glass bead-modified polymers. The coupling agent silane treatment and release agent Frekote treatment caused well-bonded particles and poorly-bonded particles with the epoxy matrix. Both of the surface treatments result in a significant increase in the toughening performance. Toughening mechanisms of plastic void growth and crack deflection caused by the addition of the glass beads were found on the fracture surfaces of the tested specimens.
Design and Simulation Analysis of Lightweight HDPE Milk Bottle
Authors: Huang Hsing-Hui , Chen Li-Wen , Lu Wei-Hua , Lin Wei-Cheng , Chen Yung-Chuan
Published: September 2018

A lightweight design is proposed for a 2800 ml HDPE milk bottle. In designing the bottle, a three-dimensional elastic-plastic dynamic finite element model is first constructed to explore the effect of the bottle thickness on the critical load and stress distribution. The validity of the proposed model is confirmed by comparing the numerical results for the load-displacement response of the bottle with the experimental results. A parametric analysis is then performed to examine the effects of the body thickness and bottom thickness on the critical load and weight of the HDPE bottle. The results show that the critical load increases with an increasing body thickness, but is insensitive to the bottom thickness. Finally, a lightweight design is proposed in which the structural shape of the original bottle is retained, but the thickness is varied in different regions of the body in order to reduce the weight. It is shown that the redesigned bottle achieves the same maximum top-load 315 N, but reduces the weight by 21.4% compared to the reference design obtained in the parametric analysis.
Shear Strength of Concrete Wide Beams Shear Reinforced with GFRP Plates
Authors: Kim Min Sook , Kang Joowon , Lee Young Hak
Published: September 2018

This paper discusses the experimental results on the shear behavior of concrete wide beams reinforced with glass fiber reinforced polymer (GFRP) plates as shear reinforcement. In order to examine the shear performance, a total of six concrete wide beams were manufactured and tested. All the specimens were designed to have the same number of legs of shear reinforcement. The transverse spacing of shear reinforcement was considered as a variable to investigate the influence of transverse spacing of concrete wide beams. From the test results, it is observed that the shear strength increased when transverse spacing of the shear reinforcement decreased. In addition, an equation is proposed to predict the shear strength of concrete wide beams in order to consider the influence of transverse spacing of the shear reinforcement. The equation is based on the test results and modified ACI 318–14. It is verified that the proposed equation is considered to be better than ACI 318–14.
Study on the Crystallization Activation Energy of Poly (L-lactic acid) Nucleated with P-tert-butylcalix[8]arene
Authors: Shi Yaoqi , Wen Liang , Xin Zhong
Published: September 2018

The crystallization activation energy (Δ E) of a polymer comprises the nucleation activation energy Δ F and the transport activation energy Δ E*. In this paper, the Δ E of poly (L-lactic acid) (PLLA) nucleated with nucleating agent p- tert-butylcalix[8]arene (tBC8) was calculated. The results showed that the Δ E of nucleated PLLA was 165.97 kJ/mol, which is higher than that of pure PLLA. The reason why Δ E of PLLA increased when incorporating nucleating agent was studied. The increment of glass transition temperature ( Tg) for nucleated PLLA revealed that the polymer chain mobility was restricted by tBC8, which was considered as the reason for the increase of Δ E*. Further, polyethylene glycol (PEG) was added to improve the chain mobility, thus eliminated the variation of the transport activation energy Δ E* caused by tBC8. Then the effect of the increment of crystallization temperature range on the increase of Δ F was also taken into consideration. It was concluded that both decreasing the mobility of chain segments and increasing the crystallization temperature range caused an increase of Δ E for PLLA/tBC8.
Accelerated Ageing of Alkali Treated Olive Husk Flour Reinforced Polylactic Acid (PLA) Biocomposites: Physico-Mechanical Properties
Authors: Isadounene Samra , Hammiche Dalila , Boukerrou Amar , Rodrigue Denis , Djidjelli Hocine
Published: September 2018

In this study, olive husk flour was added to poly(lactic acid) (PLA) to produce fully biosourced and biodegradable composites. In particular, untreated and alkali treated particles were used to produce the biocomposites at 20 wt.% via melt extrusion followed by injection moulding. The samples were then subjected to accelerated ageing (UV irradiation and water spray at 50°C) for different amounts of time (120, 240, 360 and 480 h). The results show that accelerated ageing decreased the tensile strength (TS) and Young's modulus (YM) for both untreated and alkali treated biocomposites, but the treated particles presented a lower reduction. Further comparison was made via differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) to detect any changes in the samples.
Evaluation of Short-term Creep Behavior of PE-HD after Aging in Oil Derivatives
Authors: Pereira Ayrton Alef Castanheira , d'Almeida José Roberto Moraes , Castro Thiago Motta Linhares
Published: September 2018

The creep behavior of a high density polyethylene (PE-HD) was evaluated before and after aging in contact with gasoline and diesel oil. Four viscoelastic models were used to assess changes in creep properties of the material: three parameters model, four parameters model, stretched Burgers model and Findley Law. Viscoelastic properties, stationary creep rate and compliance were used to analyze and compare the behavior between samples. A strain increase could be seen in aged samples in comparison with as-received ones, caused by plasticization due to aging effects. An increase in flexibility and decrease in stiffness in aged samples was also noted. This work also shows that the effects of aging on the creep response of a polymeric material can be analyzed using short term creep tests.
Polymer Composites with Enhanced Thermal Conductivity and Mechanical Properties for Geothermal Heat Pump Pipes
Authors: Ma Haihong , Xu Fanglin , Zhou Zhengfa , Xu Weibing , Ren Fengmei
Published: September 2018

In this article, we report a robust strategy to prepare polymer composites with enhanced thermal conductivity and mechanical properties for geothermal heat pump pipes, in which high density polyethylene (HDPE) used as matrix, various inorganic fillers including zero-dimensional (0D) aluminium spherical particles (Al-SPs), one-dimensional (1D) carbon fibres (CF) and two-dimensional (2D) graphite platelets (GPs), used alone or blended as modifier. The as-prepared polymer composites are GPs/HDPE, GPs/CF/HDPE, GPs/Al-SPs/HDPE and GPs/CF/Al-SPs/HDPE. Thermal conductivity and mechanical properties of these polymer composites were characterised. The results indicate that of all these as-prepared polymer composites, GPs/CF/Al-SPs/HDPE composites are the only one which possesses preferable and comprehensive properties both in thermal conductivity and mechanical properties due to the synergistic effect of filler. The thermal conductivity, elongation at break and tensile strength of GPs/ CF/Al-SPs/HDPE composites prepared with GPs (9 wt%), CF (3 wt%) and Al-SPs (3 wt%) were 0.803 W m−1K−1, 70.6 % and 26.69 MPa, respectively, which could meet the commercial requirements of the geothermal heat pump pipes.
Characterisation of Pulsed-Fibre-Laser-Perforated Polymeric Food Package Films
Authors: Ovaska Sami-Seppo , Leminen Ville , Tanninen Panu , Manninen Matti , Mielonen Katriina , Matthews Sami , Lindell Henry , Backfolk Kaj
Published: September 2018

A packaging material requires a proper interaction with regard to water vapour transmission between the product and the outside environment. For many fresh food products such as bakery goods, fruits, and vegetables, microperforation is utilised to extend the shelf life of the foodstuff and to provide better food quality. The microperforation potential of five commercial polymeric films has been evaluated using a pulsed fibre laser technique, and significant differences were found between the films in the penetration of the laser beam and in the diameter of the perforation. Breathable polymeric packaging films were prepared with an average laser power of 20 W and a pulse duration of 200 ns. The numbers of holes (80 μm in diameter) in the films were approx. 2000 holes/m2 and 4000 holes/m2. As expected, the number of perforations affected the water vapour transmission (WVT): the WVT was 11 g/m2/d for unperforated film, and 60 g/m2/d for the film with 4000 holes/m2, indicating that the fibre laser can be used successfully for microperforating this type of polymeric films. However, microscopic and microtomographic analyses revealed major differences in hole formation behaviour and in the wall structures of the microperforations.
Investigation on the Influence of Various Kinds of Soaps on the Mechanical Properties of Silica Filled Composites Based on Natural Rubber
Authors: Al-Hartomy Omar A. , Al-Ghamdi Ahmed A. , Al-Said Said A. Fahra , Dishovsky Nikolay , Mihaylov Mihail , Ivanov Milcho
Published: September 2018

The aim of this study was to investigate the influence that different fatty acid zinc salts had on the rheological, curing and mechanical properties of natural rubber based composites filled with silica and containing bi-functional organosilanes in the presence or absence of zinc oxide. The results demonstrated that the combination of zinc oxide and zinc soaps had a strongly pronounced anti-reversion effect. The absence of reversion in the cure curves of the rubber compounds comprising a combination of zinc oxide, stearic acid and zinc soaps, results in retention of their mechanical properties, even after overcure.
Tensions in the periphery: Dependence and the trajectory of a low-cost productive model in the Central and Eastern European automotive industry
Authors: Adăscăliței Dragoș , Guga Ștefan
Published: September 2018

This article analyses the productive strategy adopted by Renault for its Dacia plant in Romania. It proposes a detailed analysis of the conditions for the success of the Logan project – Renault’s radical approach to the concept of the low-cost automobile. We look into both market- and production-related aspects that have made the Logan work and highlight the tensions sparked by Renault’s drive to capitalize on its favourable market situation as well as the success achieved by Dacia’s workers in defending their interests. In particular, we emphasize the company governance compromises that have shaped industrial relations at Dacia over the past decades and show how in recent years the maintaining of such a compromise has come increasingly into question due to threats by automation and relocation in a context of constantly rising wages and improving working conditions. Finally, we discuss the strategic dilemmas facing both management and labour and their possible resolutions, as well as the relevance of the Dacia case for understanding the future of Central and Eastern Europe as a peripheral region attracting automotive foreign direct investments.
Long-Term Performance of Buybacks in India
Authors: Seal Jayanta Kumar , Matharu Jasbir Singh
Published: September 2018

This study tries to find out the post-announcement performance of the buyback firms over the long term in India using data from the Bombay Stock Exchange (BSE). We have chosen the event study methodology and compared the performance for a one-year, a three-year, and a five-year period. The benchmarks chosen are the Sensex, the BSE 500, the size matched firms and the size and industry matched firms. The findings of the study show overperformance by buyback firms when compared to the Sensex and the BSE 500 but no conclusion can be drawn when compared to the size matched firms and size and industry matched firms.
Cognitive Antecedents of Family Business Bias in Investment Decisions: A Commentary on “Risky Decisions and the Family Firm Bias: An Experimental Study based on Prospect Theory”
Authors: Fang Hanqing “Chevy” , Siau Keng L. , Memili Esra , Dou Junsheng
Published: September 2018

Lude and Prügl explored “family business bias,” a cognitive tendency where the family nature of a firm can often reduce investors’ perceived risk in investments. As a result, investors would display lower risk-avoidance in the gain domain and reinforced risk-seeking in the loss domain. We expanded the authors’ work by introducing four cognitive factors (anchoring, representativeness, stereotype heuristic, and information availability) that can explain the underlying mechanisms behind the prevalence of “family business bias” and other cognitive misperceptions surrounding family businesses when it comes to investment decisions.
The Missing Link? Modernization, Tolerance, and Legislation on Homosexuality
Authors: Hildebrandt Achim , Trüdinger Eva-Maria , Wyss Dominik
Published: September 2018

Research suggests that modernization is an important driver of liberalization in the field of gay and lesbian rights. Surprisingly, it has often been assumed—but not empirically examined—that a culture of tolerance mediates the relationship between socioeconomic modernization and liberal legislation. This article closes this gap by analyzing the seventy-three countries that took part in the fifth and sixth waves of the World Values Survey. As government responsiveness to public attitudes is structurally enforced by means of electoral accountability in democracies, but not in autocracies, we, in addition, distinguish between these regime types in an analysis of moderated mediation. We show that tolerant attitudes toward homosexuals do, indeed, mediate the influence of modernization on gay and lesbian rights policies in democracies, but not in autocracies. The result is confirmed by extensive robustness checks, including an instrumental variables approach to account for a potential reverse causality between tolerance and rights. The study does not only underline the relevance of cultural aspects of modernization, but also points to the crucial importance of regime type for a translation of public opinion into policy.
Development of optimal controller design method to compensate for vibrations caused by unbalanced force in rotor system based on Nyquist diagram
Authors: Yabui Shota , Inoue Tsuyoshi
Published: September 2018

In this paper, an optimal controller design method is proposed to compensate for vibrations caused by unbalanced force in the rotor system. The vibrations caused by unbalanced force are the major root cause of excessive whirling vibration in the rotor system, and it is important to compensate for the vibration to maintain its stable operation. The proposed design method can optimize a performance of the controller based on the vector locus of open loop characteristics on the Nyquist diagram. To verifiy the effectiveness, the proposed design method was employed for three typical active vibration control methods. The experimental results show that the proposed method can design the optimal parameters to compensate for the whirling vibrations of the rotor system.
Placement in Care in Early Childhood and School Readiness: A Retrospective Cohort Study
Authors: Wall-Wieler Elizabeth , Roos Leslie L. , Lee Janelle Boram , Urquia Marcelo L. , Roos Noralou P. , Bruce Sharon , Brownell Marni
Published: September 2018

The current study examined school readiness for children placed in care of child protection services before age 5. This association was assessed using a population-based cohort of children born in Manitoba, Canada, between 2000 and 2009 ( n = 53,477) and subcohorts of discordant siblings (one sibling taken into care, one sibling not taken into care; n = 809) and discordant cousins ( n = 517). In the population analysis, children placed in care were significantly less likely to be ready for school; this difference was not seen in the discordant sibling or cousin analysis. The findings suggested that differences in school readiness for children placed in care are a result of broader social factors affecting families, not placement into care.
Clinicopathologic Features and Chromosome 12p Status of Pediatric Sacrococcygeal Teratomas: A Multi-institutional Analysis
Authors: Mylonas Konstantinos S , Kao Chia-Sui , Levy David , Lordello Leonardo , Dal Cin Paola , Masiakos Peter T , Oliva Esther
Published: September 2018

Chromosome 12p gains are typically present in postpubertal male patients with testicular malignant germ cell tumors, including most teratomas, and absent in pure ovarian teratomas, both mature and immature. We sought to evaluate the clinicopathologic features and chromosome 12p status of pediatric patients with sacrococcygeal teratomas (SCTs) using the institutional databases of 2 tertiary medical centers. Seven mature teratomas (3 pure, 2 with yolk sac tumor, 1 with medulloepithelioma, and 1 with ependymoma) and 3 immature teratomas (2 pure: grade 2 and grade 3 and 1 mixed: grade 3 with yolk sac tumor) were identified. All patients underwent surgery and 2 received adjuvant chemotherapy. Fluorescence in situ hybridization analysis was performed to elucidate chromosome 12p gains, including isochromosome 12p. All 10 tumors analyzed lacked 12p gains regardless of the components. No patient had evidence of disease at their most recent interval follow-up (mean: 30, range: 7–91 months), irrespective of margin status or of receiving chemotherapy. Overall, our study suggests an absence of chromosome 12p abnormalities in clinically nonaggressive SCTs. Additional data are required to confirm these findings before definitive patient care recommendations can be made.