bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasticizing Polystyrene with Waste Leather Buffing Dust: A Drive towards Waste-Polymer Composite Synthesis
Authors: Basak Ganesh Chandra , Goswami Luna , Chattopadhyay Buddhadeb , Bandyopadhyay Abhijit
Published: September 2018

This is the first report on the use of waste chrome-tanned Indian leather buffing dust for plasticizing atactic polystyrene (PS). There is no effective re-use of waste leather buffing dust reported till today. This waste material, after preliminary characterization, has been dispersed in solvated polystyrene. Resultant composites prepared therefrom via solution cast method exhibit a drastic drop in surface hardness up to certain modifier concentration, beyond which it increases. Addition of surfactants during dispersion of the buffing dust at the optimum level further reduces surface hardness. Para-toluene sulphonic acid (PTSA) has been found to be a better compatibilizer than more conventional sodium lauryl sulphate (LS) in this system. The compatibilized composites show substantial “yield behaviour” when stretched and the breaking strain has been improved drastically from 0.2% in pure polystyrene to 25% in PTSA compatibilized system without any loss in strength. Accordingly, the breaking energy has been increased to much greater than that of the virgin polymer. Effective plasticization of the composites has lowered the glass transition temperature (Tg); PTSA containing composite has shown the minimum value, possibly due to generation of more free volume around the rigid polystyrene molecules on account of its effective adsorption over finer dust particles. Accelerated thermal degradation study shows greater thermal stability of the composites as compared to virgin polymer and this possibly resulted due to the presence of chromium content in the waste, which acts as heat sinks.
Tensile Failure Strength Analysis and Experimental Confirmation of Stitch Reinforced Composite of T-stiffened Structure
Authors: Shi Qinghua , Dai Di , Cao Zhenghua
Published: September 2018

Based on the progressive failure analysis method, taking account of 7 kinds of failure modes: stitch thread failure mode, resin extend (or compress) failure mode, fibre extend (or compress) failure mode, extend (or compress) delamination failure mode, a new failure analysis FE model was proposed for predicting the tensile strength of stitch-reinforced composite T-stiffened structures. The 3D solid element and truss element were used to simulate laminate and stitch thread individually in the FE model. The Hashin failure criterion and stiffness degradation technology are used to analyze damage failure of the stitch T-stiffened structure. Comparing the initial and final damage failure strength with those of experiments on stitch composite T-stiffened structures validated the Python secondary development program for the FE model presented in the paper. There was good agreement between the failure strength from the damage failure analysis and that of the experiment. This indicated that the model was correct, and that it could be a reference for stitch-reinforced composite design and analysis.
Well-Aligned ZnO Nanotube/Polyaniline Photocatalysts for Enhanced Photocatalytic Performances
Authors: Lin Lin , Wu Qingsheng
Published: September 2018

A well-aligned ZnO nanotube array has been successfully synthesized without depositing a layer of ZnO seeds, for the first time, on a glass substrate by a hydrothermal reaction. Subsequently, the oriented ZnO nanotube array was integrated with polyaniline (PANi) to form hybrid ZnO nanotube/PANi photocatalysts, which showed excellent photocatalytic activity for the photodegradation of Rhodamine B (RB). It was found that the photocatalytic performance under ultraviolet and visible light irradiation depended on the doping level of PANi. An investigation of photodegradation kinetics of RB indicated that the photocatalytic process showed first-order kinetics. The photodegradation mechanisms of RB dye under ultraviolet and visible light irradiation were also investigated.
Instability of the Performances of FRP Composites Implemented in Civil Engineering Environment: Experimental Study and Durability Implications
Authors: Marouani S. , Curtil L. , Hamelin P.
Published: September 2018

Various aspects related to the durability of Fibre Reinforced Polymer (FRP) composites used in the rehabilitation, repair and strengthening of existing concrete structures were studied as a function of cure behaviour. The performance of these FRP-composites containing thermoset matrix and implemented under civil engineering conditions, is unstable and their properties will change over time due to their partial cure. The present work attempts to raise awareness about the characteristic changes of FRP-composites materials immediately after their ambient cure, while emphasizing the implication of such phenomena on the durability. Both glass transition temperature Tg and mechanical characterization tests were performed to identify the effects of curing on thermorheological and mechanical stability of the composites immediately after the implementation. The experimental results indicate that overall composite performance was sensitive to the cure conditions. The implication of this sensitivity on the durability of FRP-composites was addressed and clearly identified through accelerated and natural exposure tests which reflected the civil engineering environment.
Flame Retardancy and Non-isothermal Crystallization Behaviour of PET/TiO2 Nanocomposites
Authors: Zhang Jianjun , Ji Quan , Shen Xiuhong , Xia Yanzhi , Tan Liwen , Wang Fengjun , Kong Qingshan
Published: September 2018

Titanium dioxide particles (TiO2) have been melt-compounded with poly(ethylene terephthalate) (PET) by using a twin-screw extruder to prepare PET/TiO2 nanocomposites. The flame retardancy and non-isothermal crystallization behaviour of PET and PET/TiO2 nanocomposites have been studied using several techniques. The effects of TiO2 on the combustion behaviour of PET/TiO2 nanocomposites were analyzed by CONE and SEM. The results showed that the HRR, THR and TSR of nanocomposites was reduced significantly. The char residues were examined using scanning electron microscopy, indicating that TiO2 addition produced consistent and compact char crusts. The non-isothermal crystallization behaviour of PET and PET/TiO2 were investigated by differential scanning calorimetry (DSC). Meanwhile, the kinetics of non-isothermal crystallization was analyzed by the Mo Zhishen method. Both results showed that the TiO2 in PET acted as an effective nucleation agent. Not only was the crystallization rate of composites obtained higher than that of the neat PET, but also the crystallization time of the composites obtained was shorter than that of the neat PET. The presence of TiO2 changed the mechanism of the nucleation and accelerated the rate of PET crystallization.
Polyvinyl Alcohol Engineered Cementitious Composite (PVA-ECC) for the Interfacial Bond Behaviour of Glass Fibre Reinforced Polymer Bars (GFRP)
Authors: Kim B. , Lee J-Y.
Published: September 2018

This paper presents experimental investigations of the interfacial bond behaviour of different types of rebar (steel, sand-coated GFRP, and helically-wrapped GFRP bars) and cementitious composites with and without polyvinyl alcohol (PVA) fibre. A total of 27 cubic specimens were prepared, and different PVA fibre volume fractions of 0%, 1% and 2% were added. The effects of PVA fibre on the compressive strength and interfacial bond strength were not significant. However, PVA fibre in engineered cementitious composites apparently changed the failure mechanisms during the pullout of both the steel and the helically-wrapped GFRP bars. The increase in PVA fibre volume fraction significantly improved the ductility of the matrix. Specifically, the helically-wrapped GFRP bar demonstrated the greatest improvement in ductility, while the sand-coated GFRP bar resulted in frictional pullout of the rebar due to the complete slip failure of the resin, regardless of the fibre content. Finally, the application of PVA-ECC to the helically-wrapped GFRP bar was found to be effective as replacement for steel rebar with respect to the ductility of the interfacial bond.
Preparation of High Molecular Weight Poly(vinyl carbazole)/Polystyrene Blend Web by Electrospinning
Authors: Kim Hee Sam , Lee Ki Bum , Lee Young Jae , Kim Min Jae , Cha Jin Wook , Oh Tae Hwan , Noh Seok Kyun , Lee Yong Rok , Han Sung Soo , Shin Eun Joo , Gal Yeong Soon , Lyoo Won Seok
Published: September 2018

To prepare fine and even poly(N-vinyl carbazole) (PVCz)/polystyrene (PS) blend webs, we performed a series of experiments varying processing parameters, including the type of solvent, PVCz/PS blend ratio, applied voltage, and tip to the collector distance (TCD). It was found that the morphology and the average diameter of PVCz/PS blend web were strongly correlated with electrospinning conditions. The morphologies of PVCz/PS blend webs were beaded or fine fibre structures, depending on the blend ratio of PVCz and PS. Increasing content of PS in the spinning solution tended to produce higher spinnability and the average diameter of electrospun web became smaller. The average diameter of the PVCz/PS blend web was slightly decreased with increasing applied voltage. In the case of TCDs, there was no significant effect on the PVCz/PS blend web morphologies but on increasing the TCD, the average diameter of the PVCz/PS blend webs slightly decreased.
Fabrication and Characterization of PVA/SPI/SiO2 Hybrid Fibres via Electrospinning Technique
Authors: Wang Hualin , Jiang Qin , Jiang Suwei , Jiang Shaotong
Published: September 2018

In this work, an electrospinning technique was developed for the fabrication of poly(vinyl alcohol) (PVA)/soy protein isolate (SPI)/SiO2 hybrid fibres with PVA, SPI and tetraethyl orthosilicate (TEOS) as precursors. The effects of SiO2 content, sodium dodecylsulfate and electrospinning electrical field strength on the morphology and structure of the hybrid fibres were investigated. Scanning electron microscopy (SEM) showed that uniform hybrid fibres about 200 nm in diameter were obtained at a weight ratio of PVA to SPI 8:2, SiO2 content 5.0 wt.%, sodium dodecylsulfate 0.6 wt.% and electrical field strength 0.90 kV cm-1. X-ray diffraction (XRD) patterns showed that the crystalline structure of PVA was somewhat destroyed as PVA was hybridized with SPI and SiO2, and further destroyed under electrospinning process as the stretched molecular chains of the fibre solidified rapidly at high elongation rates, resulting in the amorphism of PVA/SPI/SiO2 hybrid fibres. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) showed that the components of PVA, SPI and SiO2 nanoparticles were linked by hydrogen bonds or Si–O–C bonds in the hybrid fabric networks. Differential scanning calorimetry (DSC) tests showed that the presence of SiO2 nanoparticles considerably improved the thermal stability of the hybrid fibres. Therefore, the PVA/SPI/SiO2 hybrid fibres may have potential as a new fibre in dressings, tissue engineering or drug delivery.
Density and Water Absorption of Sugarcane Bagasse-Filled Poly(vinyl chloride) Composites
Authors: Wirawan Riza , Sapuan SM , Yunus Robiah , Abdan Khalina
Published: September 2018

Sugarcane bagasse is divided into two main components, pith and rind, with “pith” representing the inner part of the sugarcane bagasse and “rind” the outer part. In this study, both part of bagasse and were used separately as a filler in poly(vinyl chloride) to construct a natural fibre thermoplastic composite. The bagasse incorporated in poly(vinyl chloride) using internal mixer followed by hot-pressing to obtain a plate of sugarcane bagasse/PVC composite with various filler loading (10%, 20%, 30%, and 40% in weight). Density of the composites was determined and the composites were subjected to water immersion tests in order to study the effect of filler loading and fibre source on the density and water absorption behaviour. It was observed that the physical properties were influenced significantly by both fibre source and fibre content.
Synthesis and Characterization of Montmorillonite-Carbon Nanotubes Hybrid Fillers for Nanocomposites
Authors: Madaleno Liliana , Pyrz Ryszard , Jensen Lars R. , Pinto José J. C. , Lopes Augusto B. , Dolomanova Viktoriya , Schjødt-Thomsen Jan , Rauhe Jens Chr. M.
Published: September 2018

Montmorillonite-carbon nanotubes hybrids were prepared by growth of carbon nanotubes (CNT) on five different types of iron-montmorillonite clays using the chemical vapour deposition (CVD) method. Microscopy studies revealed the presence of carbon nanotubes protruding from clay surfaces and linking the clay layers in a network structure. X-ray diffraction results showed changes in the clay interlayer spacing induced by growth of carbon nanotubes within the layers of iron-montmorillonites. The quality of the resulting carbon nanotubes was evaluated by Raman spectroscopy and thermogravimetric analyzes were used to evaluate the amount of carbon nanotubes and its thermal stability. The method used for the preparation of the iron-montmorillonites appeared to be critical for the quality and quantity of carbon nanotubes obtained in each hybrid. In a preliminary study the hybrids were used to reinforce polyurethane nanocomposite foams.
Fracture Toughness of Laminated Composites – A Non-Linear Analysis
Authors: Rizov V. , Mladensky A.
Published: September 2018

Non-linear fracture behaviour of laminated composite materials under mode I (crack opening) loading conditions was studied experimentally and theoretically. For this purpose, single edge notched tension (SENT) tests were carried-out using displacement-controlled loading under room temperature dry conditions. It was found that the load-displacement diagram had non-linear character prior to onset of macroscopic crack propagation. Thus, the main objective of this paper was to study the fracture properties using non-linear fracture mechanics. A two-dimensional finite element model was set-up in order to analyze the non-linear response of the SENT test specimen. Non-linear deformation due to damage was simulated using the Tsai-Hill failure criterion. The failure analysis revealed that the damage was localized in the vicinity of the crack tip. The fracture response was characterized using a J-integral. It was shown that a realistic appraisal of the potential for crack growth should include the effects of non-linear material deformation. It was found that taking into account the non-linear deformation increased the fracture resistance. This finding was attributed to the increased strain energy dissipation due to the damage induced non-linear behaviour of the SENT test specimen.
Studies on Thermomechanical Characteristics of Poly(Methyl Methacrylate) and Ethylene-Methyl Acrylate Copolymer Blends
Authors: Poomalai P. , Varghese T.O. , Siddaramaiah
Published: September 2018

Blends of poly(methyl methacrylate) (PMMA) with ethylene - methyl acrylate (EMA) copolymers of different compositions, viz. 95/05, 90/10, 85/15 and 80/20 wt.% were prepared by a melt mixing technique using a twin-screw extruder. The blends were characterized by thermo-analytical methods, viz. differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The TGA of PMMA/EMA blends show that thermal degradation takes place in two steps and the temperature of the decomposition rate maximum is proportional to the compositions of the blends. The DSC studies reveal two glass-transition temperatures (Tg) for all the blends corresponding to their individual components which indicates that the blends are incompatible. The DMA thermograms exhibit two steps in the dynamic modulus-temperature curves for higher EMA content, which is characteristic of immiscible polymers in a two phase system.
The Development of a Polymer Composite Filament for Thermo-sensitive Applications
Authors: Sun Danmei , Vadodaria Ketan , Stylios George K.
Published: September 2018

A type of smart thermochromic filament has been developed, composed of 35% UMB Blue and 65% polypropylene. It was able to change colour between white and blue depending on the temperature. A set of examinations including DSC, SEM, XRD, FTIR and tensile strength test, has been carried out to study the properties of the smart filament. The successful development of the thermochromic filament will enable textile based smart products to be developed for applications where the effect can be indicated by the change of colour.
Bentonite-acrylamide-histidine-Cu(II) Microcomposite for Cytochrome c Adsorption
Authors: Akkaya Birnur , Akkaya Recep
Published: September 2018

Bentonite-acrylamide-histidine with an average particle diameter of 200-1000 μm was produced by bulk polymerization of bentonite, acrylamide, bisacrylamide, AIBN and histidine. Bentonite-acrylamide-histidine-Cu(II) microcomposite was prepared by loading copper ions. The microcomposite was characterized by scanning electron microscopy (SEM), specific surface area and elemental analysis. Cytochrome c adsorption studies were performed, for the first time, by using the new metal chelated affinity support (bentonite-acrylamide-histidine-Cu(II)) microcomposite in batchwise experiments.
Morbillivirus-associated lipid pneumonia in Arctic foxes
Authors: Stimmelmayr Raphaela , Rotstein David S. , Maboni Grazieli , Person Brian T. , Sanchez Susan
Published: September 2018

We describe lipid pneumonia in 5 of 24 Arctic foxes ( Vulpes lagopus) in association with morbillivirus infection, and lymphoid depletion in 3 of these 5 foxes. Canine distemper virus (CDV) immunohistochemistry yielded positive staining in lung, lymph nodes, spleen, adipose tissue, and renal pelvic urothelial cells in 5 cases. Liver and bone marrow samples collected from these cases tested positive for morbillivirus by reverse-transcription PCR assay. Strains belonged to the CDV Arctic lineage based on sequencing of the hemagglutinin gene followed by phylogenetic analysis. Phylogenetic analysis of the phosphoprotein gene showed that the identified CDV strains were not closely related to any previously documented strains responsible for outbreaks in different animals in other parts of the world.
Development of shape memory alloy actuator integrated flexible poly-ether-ether-ketone antenna with simultaneous beam steering and shaping ability
Authors: Kalra Sahil , Bhattacharya Bishakh , Munjal Bhawdeep Singh
Published: September 2018

Active control of antenna radiation by mechanical reconfiguration has large potential applications in space as well as in ground segment. Such reconfigurable antenna primarily has two functionalities: beam steering and beam shaping. While previous research has shown individual control of these functions; we have developed a suitable antenna actuation system which takes care of both the functionalities. To demonstrate our concept, we have fabricated a 1-m diameterC-band flexible reflector of poly-ether-ether-ketone using precisely machined aluminum mold. A periphery feed structure is connected to the center of the reflector by a goose-neck-shaped supporting frame. Next, we have designed and developed a smart control-disk containing two types of shape memory alloy actuator-based self-locking devices. A group of actuators are used for locking/unlocking the rotational degree of freedom of the antenna; while the other group generates deformation of antenna at the desired direction. An 8-bit absolute encoder is installed with each locking device to sense and feedback the displacement of a control point. We have achieved a controllable deflection up to 25 mm with a precision of 0.3 mm with this system. A directional precision of [Formula: see text] is also achieved simultaneously. Presently, we have developed eight such actuation points on the disk to control the shape of the antenna. For numerical simulation of the structural deformation and study of the radio frequency pattern, finite element analysis is carried out using ABAQUS, and the far-field radiation pattern corresponding to the deformed shape is obtained. The electromagnetic patterns are analyzed using geometric optics technique. Finally, a methodology of achieving surface coordinates for desired radiation pattern is presented. The study provides useful insights into the design of flexible and reconfigurable antenna system.
Reviewing Work Team Design Characteristics Across Industries: Combining Meta-Analysis and Comprehensive Synthesis
Authors: Carter Kameron M. , Mead Brandon A. , Stewart Greg L. , Nielsen Jordan D. , Solimeo Samantha L.
Published: September 2018

This article presents a comprehensive synthesis and quantitative review of studies examining relationships between team design characteristics and team performance. Across 398 primary studies, the present study meta-analytically investigated the effects of team composition, team task design, and team leadership characteristics on team performance. The study further investigates how the effects of these team design characteristics differ according to the industry context within which the team is embedded (high technology, manufacturing, service, or student). Overall, this review emphasizes the importance of continued inquiries focusing on team design while also discussing the implications of this review for theory, practice, and future research.
Facial Expressions and Verbal Response Strategies in Postcrisis Communication
Authors: Yao Hui-Chung , Lai Yu-Bin
Published: September 2018

This study explores how a spokesperson’s facial expressions and verbal response strategies affect participants’ evaluations of an organization’s crisis communication responses. Using a between-subjects experiment with Taiwanese participants, the study investigates the effects of congruence and incongruence between an organization’s emotional and verbal responses on participants’ perceptions of the acceptability of its crisis response. The findings suggest that an organization’s emotional response should be congruent with its verbal response strategy in order to enhance the audience’s acceptance of its crisis response and in turn protect its reputation.
Teaching Sequences of Pretend Play to Children With Disabilities
Authors: Barton Erin E. , Choi Gounah , Mauldin Evelyn G.
Published: September 2018

Children with disabilities demonstrate fewer complex pretend play behaviors than children with typical development, which might limit their social participation in early childhood settings. A multiple-probe design was used to examine the relation between a single prompt procedure—constant time delay—and the acquisition, maintenance, and generalization of sequences of pretend play by children with disabilities. Results indicated systematic instruction was functionally related to increased levels of unprompted and different sequences of pretend play in all three participants. However, individual adaptations were required for two of three participants. The findings replicate previous research on adult systematic instruction using response-prompting strategies to teach pretend play and extend the literature by measuring and reporting generalized sequences of pretend play. Overall, this study supports systematic, individualized instruction using response-prompting strategies to teach sequences of pretend play to children who do not display such behaviors.
Dynamic response of rectangular membrane excited by heavy rainfall
Authors: Zheng Zhou-Lian , Zhang Guang-Xin , Li Dong , Liu Chang-Jiang
Published: September 2018

This paper investigates the dynamic response problem of an orthotropic rectangular membrane structure excited by the heavy rainfall. Firstly, a determined model is proposed to express the load of heavy rainfall imposed on the membrane structure. Then, the geometrically nonlinear governing motion equations of the membrane structure are established based on the von Kármán’s theory, and solved by the perturbation method. Consequently, the approximated analytical solution of displacement can be obtained. Secondly, the experimental study of this dynamic response problem is carried out. The theoretical model is validated by the experimental data based on the developed artificial simulated rainfall impact system. Moreover, the effects of adding weight from the accumulated rain on structural characteristics are analyzed. Additionally, the parameter discussions varying with rainfall intensity, material properties, pre-tension, structural size, and inclined angle are made in detail. This work provides a reliable theoretical model and experimental system to study the dynamic response problem of membrane structures excited by heavy rainfall and the guidance for the dynamic design, construction and maintenance of membrane structures in practical engineering as well.
Information, Motivation, and Self-Efficacy Among Men Who Have Sex With Men and Transgender Women in the State of Maharashtra, India
Authors: Wilkerson J. Michael , Rhoton Jayson Michael , Li Dennis , Rawat Shruta Amit , Patankar Pallav , Rosser B. R. Simon , Ekstrand Maria
Published: September 2018

Background. India’s National AIDS Control Programme calls for, among other things, targeted behavioral interventions that address determinants contributing to new infections among men who have sex with men (MSM) and hijras (transgender women). Aim. To determine if the information–motivation–behavioral skills model was transferable to an Indian context. Methods. We recruited 442 MSM and 7 hijras into an online cross-sectional study that asked questions about condom use knowledge, motivation, self-efficacy, and sexual behavior. Structural equation modeling was used to test the overall information–motivation–behavioral skills structure. Results. Condom use and HIV risk knowledge did not significantly predict condom use self-efficacy or having condomless anal sex with more than one male partner in the past 3 months, and knowledge was not significantly correlated with attitudes toward barebacking. Despite this, the final structural model explained 14.4% of the variance in condom use self-efficacy and 20.0% of the variance in risky sexual behavior. Overall fit of the model was good: χ2(201, N = 447) = 445.002, p < .0001, root mean square error of approximation = .052, 90% CI [.046, .059], comparative fit index = .989, Tucker–Lewis Index = .987. Conclusion. The public health response to India’s HIV epidemic is currently different than in the West due to differences in medication access and public health infrastructure. As Indian MSM and hijras learn more about the effectiveness of viral suppression and hopefully have greater access to preexposure prophylaxis, researchers should monitor for changing attitudes toward condoms and be prepared to collaborate with the public health infrastructure in order to develop interventions that reinforce positive attitudes toward condom use.
Interface fluid syndrome secondary to endothelial failure due to toxic anterior segment syndrome after cataract surgery
Authors: Kasım Burcu , Koçluk Yusuf , Burcu Ayşe
Published: September 2018

Purpose:

To present a case of previous laser in situ keratomileusis with interface fluid syndrome secondary to toxic anterior segment syndrome following cataract surgery.

Case report:

A 52-year-old woman, complaining blurred vision in her right eye for 18 months after cataract surgery, was referred to our clinic. She was diagnosed with toxic anterior segment syndrome, postoperatively, which resolved in 3 days. She had a history of laser in situ keratomileusis surgery 15 years ago. Slit-lamp examination of the right eye showed corneal haze, limited to laser in situ keratomileusis flap. The patient was diagnosed with interface fluid syndrome secondary to endothelial decompensation due to toxic anterior segment syndrome. Descemet’s membrane endothelial keratoplasy was performed along with full thickness fenestrations in the laser in situ keratomileusis flap to the right eye of the patient. The fluid was resolved in 1 week and visual acuity was improved rapidly.

Conclusion:

This case shows the importance of considering the diagnosis and determining the specific etiology of interface fluid syndrome, even years after the laser in situ keratomileusis surgery, when endothelial cell function has been compromised with any factor, such as intraocular surgery and its complications.
Trump’s populism, la trahison des clercs and embracing dissent
Authors: Sligo Frank
Published: September 2018

This article explores President Trump’s populist politics and its implications for scholars in communication studies, examining how Trump’s supporters need to be better understood within their own context. The thinking of Laclau, Mouffe and others, based particularly on observations of European populism, is employed to shed light on how populist social trends may undermine the legitimacy of rational public discourse and foster public acceptance of authoritarianism. Their perspective also gives insights into means by which scholars can better understand their own responsibility to avoid falling into the trap of invective-swapping seen during the US 2016 presidential campaign. In so doing, the article suggests ways whereby scholars can work towards the protection of a free society and help resolve the crisis of populism in ethical, informed and nuanced ways that help to arrest a drift to authoritarianism.
A temperature measurement method for testing lubrication system or revealing scuffing failure mechanism of spur gear
Authors: Jihua Chang , Shaojun Liu , Xiaozhou Hu
Published: September 2018

In order to meet the needs of temperature measurement for testing lubrication system or revealing scuffing failure mechanism of spur gear, a temperature measurement method analysis is carried out. This method shifts the high temperature region to a position convenient for measurement. And the measurement target including the highest temperature of gear and its location are also shifted to the new position. Considering the change of gear temperature field caused by thermal barrier covering the end face, the temperature difference of the target measurement position and the direct measurement position is analyzed by finite element method. Taking a spur gear pair as an example, its temperature field is obtained in the thermal steady state before and after shifting of temperature. The results show that temperature of the target measurement position and the direct measurement position is same in distribution, and temperature of the direct measurement position is higher than the temperature in the target measurement position. The highest temperature of the direct measurement position increases by 2.5%. As a result, considering the increment as the safety margin, it is not conservative to estimate the temperature in the target measurement position by the measured temperature data in the direct measurement position. And the measured temperature data also will help to find out the location of the highest temperature of gear in the target measurement position. Meanwhile, the accidental risk of scuffing failure can be avoided during experimental research in testing lubrication system or revealing scuffing failure mechanism by this temperature measurement method. And the comparison of the analytical results with the experimental measurement data shows good agreement.
Buckling behaviour and design of complex-shaped aluminium mullion sections
Authors: Kesawan Sivakumar , Mahendran Mahen
Published: September 2018

Thin-walled aluminium mullions are the vertical framing members of the façade systems used in buildings. This article investigates the buckling behaviour of these complex-shaped aluminium mullions. For this purpose, the aluminium mullion sections were simplified into elements of varying thickness and modelled using CUFSM finite strip analysis programme. Elastic buckling analyses were performed with and without considering the availability of glass panel restraints for both negative and positive wind actions, and the results are presented in this article. The effect of providing return flanges to enable a good connectivity between the male and female mullions was also evaluated. The lateral restraints provided by glass panels were simulated using the spring stiffness option available in CUFSM, and the analyses were performed for spring stiffness values in the range of 0–1 N/mm/mm. The applicability of the buckling analysis results to the design of aluminium mullions was then evaluated using the direct strength method. For this purpose, the section moment capacities of mullions were determined from finite element analyses and compared with the direct strength method predictions using the CUFSM buckling analysis results. This comparison showed that direct strength method–based design can be adopted for the complex-shaped aluminium mullions provided their elastic buckling capacities are available. Overall, this study has provided good understanding of the buckling behaviour of mullion sections under both positive and negative wind actions and has proposed the use of direct strength method for the design of aluminium mullion sections.
Tannin Treated Water for use in the Emulsion Polymerization of SBR. Evaluation of Rubber Characteristics
Authors: de Oliveira Isabele Mendes , Cruz Vinicius , Visconte Leila L.Y. , Dezotti Marcia W. de C.
Published: September 2018

The use of products from vegetal source, as tannins, in the treatment of industrial waters has been the focus of increasing attention since it contributes to a reduction of the toxicity brought about by the residues generated during the water treatment process. Nevertheless, in an industrial plant any modification to be introduced in the production process has to meet a few standards as the new procedures can alter the characteristics of the final product. In this work, tannin was used to treat the water for the production of emulsion SBR and the characteristics of the rubber obtained are evaluated. As SBR is an extensively used general purpose rubber, the properties must be kept as close as possible to those presented by the product prepared with water treated in the conventional way. Thus, a comparative study was done, by carrying out emulsion polymerizations in water treated conventionally with aluminum sulfate or with tannin. The results show that the presence of tannin does not significantly affect the characteristics of the final product as long as its concentration is carefully controlled.
Influence of Composition and Crosslinking on Mechanical and Thermal Properties of Recycled Polyethylene/EVA Mixtures
Authors: Zattera A.J. , Bianchi O. , Oliveira R.V.B. , Canto L.B. , Ferreira C.A. , Zeni M.
Published: September 2018

This study aims to investigate a recycling alternative for a crosslinked ethylene-vinyl acetate (EVA-c) copolymer (75 wt% of gel content) from the shoe industry through mixing with virgin and recycled polyethylenes. The Drais equipment, an ultra-high-speed thermo-kinetic mixing and compounding system specifically developed for very difficult compounding, mixing and dispersion applications, was chosen for processing highly loaded EVA-c (60-90 wt%) compounds. PE/ EVA-c mixtures presented additive or synergistic mechanical properties, which reveals good compatibility between the polymers. The addition of dicumyl peroxide (DCP) as a crosslinking agent was also evaluated. The PE/EVA-c/DCP mechanical properties were found to be influenced by the degree of crosslinking; significant softening was observed for mixtures with DCP contents higher than 2 phr, that is, with maximum gel content. It is proposed here that the softening caused by DCP addition was related to a decrease in the degree of crystallinity; although the crosslinking process itself make polymeric materials more rigid, for semicrystalline polymers it causes defects in their crystalline arrangement, increasing the volume of amorphous phase, i.e., the crosslinking process induces a decrease in the degree of crystallinity of PE/EVA-c mixture, presenting a rubber-like behavior. Therefore, the use of the recycling procedure developed in this work represents an alternative for crosslinked EVA-c and PE re-use through a low-cost and easy-to-handle batch mixer (Drais), making it possible to prepare materials with a range of mechanical properties suitable for technological applications.
Transport and Mechanical Properties of Styrene Butadiene Rubber/Ethylene Vinyl Acetate Blends
Authors: Padmini M. , Radhakrishnan C.K. , Sujith A. , Unnikrishnan G. , Purushothaman E.
Published: September 2018

Experimental results of sorption and desorption, obtained by a gravimetric method, have been presented for styrene butadiene rubber/ethylene vinyl acetate (SBR/EVA) blends with dichloromethane, chloroform and carbon tetrachloride as penetrants at 26°, 36° and 46 °C. The blends were crosslinked by using three different vulcanising systems viz. sulphur, peroxide, and a mixed system consisting of sulphur and peroxide. The liquid uptake tendency has been found to decreases with increase in EVA content in the blends. Transport parameters such as diffusivity, sorptivity and permeability were estimated. Attempts have been made to correlate the transport properties with the morphology of the blends. To examine the stability of the blends in solvent environment, mechanical testing was carried out for unswollen, swollen, and deswollen samples. An overall decrease in stress, strain, and elongation at break have been observed after a sorption-desorption cycle. The sorption results have been compared with relevant theoretical models.
Converting Waste Polystyrene into Adsorbent: Optimisation of Reaction Parameters and Properties
Authors: Bekri-Abbes* Imene , Bayoudh Sami , Baklouti Mohamed , Papon Eric , LeClercq Dominique
Published: September 2018

In this study, we suggest a new and efficient technique to convert common waste polystyrene into a functional exchange polymer. Waste polystyrene was crushed into small pieces and immersed in sulfuric acid solution while we varied time, dimension of particles and temperature. It was found that for a temperature above 70°C and period of treatment of 2 hours, waste polystyrene became soluble in acidic solution. Best degree of sulfonation was obtained with samples treated at 60 °C for 2 hour (17.25%) and for 40°C for 4 hours (16.87%).

For these samples, we evaluated some exchange properties such as: swelling behavior, wettability and cation exchange properties.
Evaluation of Pyrolytic Oil from Scrap Tires as Plasticizer of Rubber Compounds
Authors: Cataldo Franco
Published: September 2018

A heavy fraction of oil obtained from pyrolysis of rubber crumb derived from scrap tires was studied by H-NMR and FT-IR spectroscopy in comparison to a distillate aromatic extract (DAE) derived from petroleum and currently used as plasticizer in rubber mixes. The spectral data suggest a rough chemical analogy between the two oils although the viscosity and the density of the pyrolysis oil are significantly lower that that of the aromatic extract suggesting a significantly lower average molecular weight for the pyrolytic oil in comparison to the reference DAE oil.

The two oils were tested at 10 and 15 phr level in a NR-based formulation and the cure kinetics and the mechanical properties of the rubber compounds have been measured. The pyrolytic oil gives accelerated cure kinetics, reduced scorch safety and lower compound viscosity in comparison to reference compounds with DAE oil. The mechanical properties of the cured compounds prepared with pyrolysis oil from scrap tires appear similar to the reference compounds prepared with DAE oil. However, the ageing resistance of the pyrolysis oil are worse than the reference compound with DAE oil.
Use of Recycled Tyre Material in NR/BR Blend Based Tyre Tread Compound: Part II (With Ground Crumb Rubber)
Authors: Bandyopadhyay S. , Dasgupta S. , Agrawal S.L. , Mandot S.K. , Mandal N. , Mukhopadhyay R. , Deuri A.S. , Ameta Suresh C.
Published: September 2018

For both the environment and basic economic reasons, there is a continual interest in the recycling of scrap rubber and therefore in the development of recycling technologies. In the present work three different sizes of mechanically ground Indian crumb rubbers were characterised using different chemical and analytical methods and were used in a NR/BR blend based light commercial vehicle (LCV) tyre tread compound. Varying doses of crumb rubber were used as an additional ingredient. The minimum torque and Mooney viscosity values were marginally increased with increasing dose and mesh size of crumb rubber. A marginal deterioration in tensile strength, fatigue to failure and abrasion properties was observed. At all levels of usage, the 100 mesh size mechanically ground Indian crumb rubber retained the properties better than other lower mesh size crumb rubbers.
Molecular Transport Characteristics of Poly(ethylene-co-vinyl Acetate) in Presence of Aliphatic Chlorinated Hydrocarbons
Authors: Kumar S. Anil , Thomas Sabu
Published: September 2018

The molecular transport characteristics of poly(ethylene-co-vinyl acetate) (EVA) with aliphatic chlorinated hydrocarbons as probe molecules have been investigated by simple sorption gravimetric analysis. Uncrosslinked and crosslinked EVA membranes were prepared. The cross links were introduced by peroxide technique using dicumyl peroxide (DCP). Samples with different crosslinking densities were also prepared. The influence of crosslinking, different crosslinking density, temperature, size and polarity of penetrants on transport were analyzed. It has been observed that a critical concentration of crosslinker is necessary for maximum sorption. D1 sample showed a higher solvent uptake than the uncrosslinked sample. But when the extent of crosslinking increases, the equilibrium uptake decreases. The influence of temperature on the sorption and the activation energies of sorption have been calculated. Thermodynamic parameters were also estimated. The mechanism of transport showed anomalous behavior in all solvents. Sorption (S), desorpion (D), resorption (RS), redesorption (RD) experiments have been performed for studying the transport phenomenon. After attaining equilibrium, EVA sample was allowed to desorbe fully. The desorbed sample is then exposed to solvents for resorption followed by redesorption. Transport parameters namely diffusion coefficient, sorption coefficient and permeation coefficient have been calculated. The values of polymer-solvent interaction parameter and molar mass between crosslinks were calculated using Flory-Rehner theory. First order kinetics model was used to investigate the transport kinetics.
Research on the Application of Recycled Waste RFL (Resorcinol-Formaldehyde-Latex) Dip Solid in Styrene Butadiene Rubber Based Compounds
Authors: Bandyopadhyay S. , Agrawal S.L. , Sajith P. , Mandal N. , Dasgupta S. , Mukhopadhyay R. , Deuri A.S. , Ameta Suresh C.
Published: September 2018

Waste resorcinol-formaldehyde-latex (RFL) dip solid was collected from the suction chamber of a typical tyre industry dip unit. The physico-chemical characterization of the material was carried out, along with a fresh RFL dip solid obtained by drying a fresh dip solution. The effect of the waste material was studied in a styrene butadiene rubber (SBR) based compound in both gum and filled state. The waste material was treated with boiled water and dilute hydrochloric acid and the effect of the treated material was further studied in the SBR based filled compound. The filler dispersion, polymer-filler interaction and dynamic mechanical properties was also studied.
High Molecular Weight Tri-substituted Phenol as an Antioxidant for Rubber
Authors: Malshe Vinod Chintamani , Subramanyam Elango
Published: September 2018

Long aliphatic chain containing substituted phenols like (9-(2-hydroxy 3,5-dinonylphenyl) methyl stearate (DNPMS), (9-(2-hydroxy 3,5-dicumyl phenyl) methyl stearate (DCPMS) and (9-(4-hydroxy 3,5-ditertiary butyl phenyl) methyl stearate (DTBPMS) have been prepared by Friedel Crafts alkylation of hindered phenols such as 2,4-dinonyl phenol (DNP), 2,4-dicumyl phenol (DCP) and 2,6-ditertiary butyl phenol (DTBP) respectively with methyl oleate in presence of AlCl3 at room temperature. To study the efficacy of these compounds as antioxidants, natural rubber mixtures have been prepared. The physical and mechanical properties of the rubbers were determined. The effects of the prepared compounds on the mechanical properties after ageing were evaluated. It was found that the synthesized compounds showed good antioxidant behaviour compared with the industrially used conventional antioxidant styrenated phenol (SP). In the second part, we have studied the effect of antioxidant DTBPMS which is having structural similarity with Irganox 1076, on the ageing of NR-SBR blend vulcanizates Hawai footwear application. It was found that the DTBPMS showed delayed initial crack formation and other mechanical properties were comparable to those of vulcanizates containing Irganox 1076.
Effect of Magnetic Field on the Distribution and Orientation of Magnetic Particles in Co-injection Moulding
Authors: Ogur E.O. , Davis M.C. , Goodship V. , Smith G.F.
Published: September 2018

This paper presents a study of the effect of an external magnetic field on the distribution and orientation of magnetic particles in co-injection moulding. The orientation of the magnetic particles was determined using optical microscopy and image analysis techniques. The external magnetic field was placed in the tool cavity and used to magnetize the particles and to generate the necessary magnetic field gradient to manipulate them. The ferromagnetic nickel particles remained magnetic enough to overcome the strong drag forces imposed on them by the polymeric fluid matrix and to be orientated by the permanent magnet in the tool.
Modification of Asphalt Properties
Authors: Ashry El Sayed H. El , Awad Laila , Zaher Mohamed Abed El , Elkharashe Elsayed , Bkheat Adel A.
Published: September 2018

The change in physicochemical properties due to fluxing propane precipitated asphalt (PPA) as well as blown asphalt grade 115/15 of marine belayim Oregon with long residue (LR), short residue (SR), and aromatic extract (AE) has been investigated. The devulcanization of crumb rubber with AE and the change in physicochemical properties due to fluxing PPA with low concentration devulcanized rubber (DV) and high concentration devulcanized rubber (DV”) led to compatible asphalt samples. The vulcanization of flux of PPA with DV and DV” and studying the emulsification of rubberized and unrubberized asphalt indicated their suitability for application.
Why Seniors Leave and Why They Return: An Exploratory Case Study
Authors: Johnson Shannon L.
Published: September 2018

A recent increased focus is being placed on college completion agendas, yet there is limited research on senior attrition. Examining why students leave school when they are so close to being done and what motivated them to return when they did, this exploratory case study analyzes several data sets at one public university where a degree completion program was established to help undergraduate seniors return and graduate. Analyzing data from several sources found that the predominant reason why seniors left was for personal reasons and that intrinsic motivation best describes why they wanted to finish their degree. Barriers to graduation and future research are also discussed.