bluuebunny/crossref_metadata_2025 huggingface dataset:
High-Density Polyethylene/Ground Tyre Rubber Blends: Effective Dispersion and Mechanical Property Enhancement through Solid-State Mechanochemical Milling
Authors: Zhang Xinxing , Chen Chen , Lu Canhui
Published: September 2018

Homogeneous dispersion of high-density polyethylene (HDPE)/ground tyre rubber (GTR) blends via solid-state mechanochemical milling was demonstrated here as a low-cost and industrially scalable method to prepare high-performance polymer blends consisting of recycled tyres, thereby providing a novel strategy for rubber recycling. Morphological characterisation of these blends by fluorescence microscopy together with transmission electron microscopy (TEM)–energy dispersive X-ray (EDX) microanalysis indicated that the GTR domains with a size of ~100 nm or less were dispersed evenly in the HDPE phase after 20 cycles of milling. Meanwhile, the partial devulcanisation of GTR was realised, as confirmed by gel fraction measurements. The mechanochemically milled HDPE/GTR blends exhibited excellent mechanical properties. After 20 cycles of milling, the tensile strength of HDPE/GTR 60/40 blends was enhanced by 60.0%, and the elongation at break was over 14 times that of the conventional melt-mixed blend.
Some Factors Determining the Volume Resistivity of Filled Natural-Rubber-Based Nanocomposites
Authors: Al-Hartomy Omar A. , Al-Ghamdi Ahmed , Dishovsky Nikolay , Malinova Petrunka , El-Tantawy Farid
Published: September 2018

In recent years, special grades of electroconductive carbon black have been developed to overcome the usage of large amounts of filler in the preparation of composites with desired electrical properties. Characteristic features of the novel carbon black are its superhigh specific surface area and structure, which are many times higher than those of conventional electroconductive carbon black. The present article reports on natural-rubber-based composites, filled with carbon black of superhigh specific surface area and structure. New results concerning the influence of change in the filler concentration, applied pressure, and temperature on the volume resisitivity of the composites are presented and discussed. It has been found that the new filler lowers the percolation threshold greatly and ensures very high electroconductivity at low content. The influence of applied pressure on the volume resistivity depends on whether the amount of filler used is sufficient to reach or pass the percolation threshold: when the percolation threshold is not reached, the volume resistivity increases with increasing pressure; after reaching the percolation threshold, the volume resistivity decreases with increasing pressure. With increase in temperature, the volume resistivity of the examined composites decreases. With increase in the degree of filling, the examined hysteresis decreases too. The results obtained for the new conductive rubber composites may be considered as a novel contribution in the field of polymer materials research.
Effect of Amount of Functionalised Carbon Nanofibres in Polyurethane Dispersions
Authors: Orgilέs-Calpena Elena , Arán-Aís Francisca , Torró-Palau Ana M. , Orgilέs-Barceló Cέsar
Published: September 2018

Waterborne polyurethane (WBPU) adhesives reinforced with carbon nanofibres (CNFs) were prepared, and their properties were evaluated as a function of content (0.1–1 wt%). The incorporation of carbon nanofibres into waterborne polyurethane adhesives presents great difficulty because of their tendency to form aggregates, which prevents an efficient dispersion. It is therefore necessary to introduce functional groups on the surface of the nanofibres to improve their interaction with any polymer. In this research, carbon nanofibres were preoxidised by chemical functionalisation to enhance their stability in waterborne polyurethane adhesives. The results showed that the chemical treatment used to functionalise the carbon nanofillers and the experimental procedure employed to incorporate them into the polyurethane were adequate, as stable dispersions were obtained. Moreover, the addition of nanofibres to the waterborne polyurethanes improved their rheological and viscoelastic properties, resulting in an increase in viscosity and causing changes in the crystallisation kinetics.
Shellac as a Multifunctional Additive (MFA) in a Typical Truck Tyre Sidewall Compound
Authors: Bhattacharyya Sanjay Kumar , Chakraborty Sugata , Sharma Giriraj , Kumawat Pankaj , Dasgupta Saikat , Bandyopadhyay Samar , Mukhopadhyay Rabindra , Bandyopadhyay Abhijit
Published: September 2018

This study reports some unexplored features of naturally occurring Indian shellac present in a typical truck tyre sidewall compound, at low doses with the intention of replacing stearic acid in the formula. The chemical characterization of shellac was determined using Fourier transform infrared (FTIR) spectroscopy, along with information from earlier published reports, revealing the presence of different fatty acids, alcohols, esters and quinone-based dyes. The substitution of stearic acid with shellac shows that 50% replacement of the acid with shellac obtained comparable rheometric and physical properties with the control compound. The presence of different components in shellac further helped to improve ageing and reversion resistance. The volatile loss from shellac is much lower compared with commercial stearic acid. Some essential properties for sidewall application such as extrudate shrinkage and die swell behaviour were also found to be suitable when 50% of the commercial stearic acid was replaced with shellac in the formula.
Determining the Service Life of Polychloroprene Parts: A Case Study in Aging Behavior
Authors: Bafna Sudhir
Published: September 2018

This paper addresses determination of the service life of an installed elastomeric part, which is an issue of great practical use every day in industry. Unfortunately, this issue is commonly misunderstood and mishandled. The perennial confusion between “shelf life” and “service life” is clarified. A comprehensive survey of published literature on polychloroprene (CR or neoprene) aging is provided. The methodology, considerations and pitfalls of similarity analysis, accelerated heat aging and prediction using activation energy are illustrated with a case study. Shear in the dynamic mode, tensile, hardness, specific gravity and volume swell were the tests used to quantify the effect of heat aging. Tensile modulus and volume swell were determined to be the tests most sensitive to changes resulting from heat aging while specific gravity was the least sensitive. Although illustrated by an example of a polychloroprene part, this methodology is equally valid for the assessment of other elastomers also.
Effect of the Carbon-Silica Reinforcing Filler Obtained from the Pyrolysis-Cum-Water Vapour of Waste Green Tyres upon the Properties of Natural Rubber Based Composites
Authors: Al-Hartomy Omar A. , Al-Ghamdi Ahmed A. , Said Said A. Farha Al , Dishovsky Nikolay , Mihaylov Mihail , Ivanov Milcho , Ljutzkanov Ljutzkan
Published: September 2018

The aim of the present paper is to investigate the solid product (SiO2D, pyrolysed silica filler) obtained via pyrolysis-cum-water-vapour of waste “green” tyre treads as a reinforcing filler in natural rubber based composites. Curing characteristics, mechanical and dynamic properties of the investigated composites comprising a pyrolysed silica filler have been compared to those of the vulcanizates comprising conventional carbon black, silica or their blends. The mechanical and dynamic properties of the studied composites show that the product discussed could by all means replace the conventional fillers – carbon black, silica as well as their blends – in natural rubber based composites. Indirectly, the results obtained allow the conclusion that the product obtained from pyrolysis-cum-water vapour of waste “green” tyre treads is not a pure mechanical blend of the fillers used for the production of “green” tyres (silica and carbon black). Though some amounts of silica and carbon black are present in the product, it also contains silica with carbon deposited on its particles surface resulting from the destruction of elastomer matrix. That makes this product similar to the dual phase fillers described in literature.
Devulcanization and Recycling of Waste Automotive Epdm Rubber Powder by Using Shearing Action and Chemical Additive
Authors: Movahed S. Ostad , Ansarifar A. , Karbalaee S. , Far S. Athary
Published: September 2018

In automotive applications, ethylene-propylene-diene rubber (EPDM) is used to manufacture various components and therefore recycling scrap rubber is a major issue. The primary aim of this study was to develop a new method for devulcanizing waste automotive EPDM rubber powder by using shearing action and chemical additive and recycle the devulcanized powder. A semi-industrial twin screw extruder with a shearing action and reactor along with 2-mercaptobenzothiazole-disulfide (MBTS) chemical were used to devulcanize the waste powder at two different feed screw speeds and main rotor speeds at a constant temperature of 220°C. To recycle the devulcanized powder, different amounts of the devulcanized powder were mixed with a commercial EPDM-based automotive rubber strips compound to produce blends. The blends, commercial compound and devulcanized powder were cured with a semi-efficient (SEV) vulcanization system and their viscosity, cure and mechanical properties measured. For the blends, the Mooney viscosity was unchanged with 40 wt%, crosslink density with 20 wt%, tensile strength and elongation at break with 10 wt%, and compression set with 20 wt% of the devulcanized powder. Interestingly, the hardness benefitted from 50 wt% of the devulcanized powder in the blends. The scorch and optimum cure times shortened and the cure rate index rose when the loading of the devulcanized powder in the blends was raised. This new method offered a major new route for devulcanizing and recycling the waste powder.
Effect of Micro and Nano Zinc Oxide on the Properties of Pre-Vulcanized Natural Rubber Latex Films
Authors: Anand K , Varghese Siby , Kurian Thomas
Published: September 2018

Zinc oxide (ZnO) nanoparticles were synthesized through a solution free mechano-chemical route and their effects on pre-vulcanized natural rubber latex properties were investigated. Effect of nano ZnO loading on swelling, antimicrobial, mechanical and ageing properties of pre-vulcanized latex vulcanizates were examined and compared with conventional micro ZnO filled vulcanizates. In comparison with micro filled system, nano filled system exhibits better performance in all respects. The ageing resistance of nano ZnO incorporated latex films was found to be high.
Embedded Eggshells as a Bio-Filler in Natural Rubber for Thermal Insulation Composite Foams
Authors: Tangboriboon Nuchnapa , Pannangpetch Wasirin , Aranyik Khomkrit , Petcharoen Karat , Sirivat Anuvat
Published: September 2018

Thermal insulation composite foams were prepared from the natural rubber as a matrix phase and an eggshell powder as a calcium carbonate dispersed phase, using chlorinated polyethylene acting as a flame retardant and curing agent at the vulcanization temperature 150°C in a two-roll mill. The main composition of eggshell is calcium carbonate which is more than 96.35 wt%. The obtained composite rubber foams with 50 phr eggshell added possessed the thermal conductivity, compression set, crosslink density, bulk density, and relative foam density values equal to 0.070 W/m.K, 45.0%, 6.95 × 10−5mol/cm3, 0.58, and 0.63, respectively. The obtained composite rubber foams were of good thermal resistance, good compression set, short curing time, good crosslink density, and light weight, suitable for various applications such as automobiles, storage tank, and transport packaging. Furthermore, the scanning electron micrographs, X-ray diffraction patterns, specific heat, and physical properties (bulk density, crosslink density, and relative foam density) were taken or measured to investigate the microstructures, phase compositions, thermal properties, and characteristics of the insulating composite foams and were reported here.
The Composition and Nature of Vulcanisation Fumes in the Rubber Industry – a Technical Review
Authors: Forrest Martin
Published: September 2018

A comprehensive review of the published literature has been undertaken to achieve a thorough assessment and understanding of rubber fumes. This review has made apparent the fact that rubber fumes are not a single chemical entity, but have a very complex chemical composition which varies according to a number of factors. In addition to providing data on the individual chemical substances that are present in rubber fumes, a description is given of their different physical forms (i.e. gas and aerosol), their potential sources within the rubber compounds (e.g. volatile ingredients) and the factors (e.g. process temperature and specific processing operation) that affect their composition and physical form. This review has also shown how changes in the rubber industry and rubber technology over the past 40 years have altered the composition and level of rubber fumes and increased the level of protection for workers. Also included are recent developments in the field, such as the international standard ISO/TS 17796:2013 qualitative method for the identification of substances in rubber fumes. By carrying out analytical work using such methods, and having knowledge of the factors that affect the composition of rubber fumes, it is possible obtain a reasonable understanding of their chemical composition on a case by case basis.
Organic / Inorganic Nanosilica Support Role in the Recovery of Terephthalic Acid from Poly(Ethylene Terephthalate) Wastes
Authors: Nikje Mir Mohammad Alavi , Ghamary Elmira
Published: September 2018

In this report the efficiency of organically modified nanosilica namely, γ-glycidoxy propyl trimethoxy silane / diethanol amine (GDS) was evaluated in the recovery of terephthalic acid from poly (ethylene terephthalate) wastes received from used soft-drink bottles. In this study, organically modified nanosilica used as the solid support, diethylene glycol (DEG) as the solvent and sodium hydroxide as the catalyst and the support performances was examined in detail and the results were compared with unsupported reaction. Results showed that (GDS) delivered good performance as the reagent and solid support in depolymerizing of poly (ethylene terephthalate) to the terephthalic acid. The highest terephthalic acid (86%) recovery yield was reached at NaOH (0.3 g), GDS (0.02 g) and PET: waste molar mass ratios (1:3), respectively. In addition, obtained data showed that in the presences of GDS (0.02 g) required reaction time for complete glycolysis decreases up 98% and by exceeding the GDS to 0.05 g, the consumption of the solvent decreases to 62.5% in comparison with unsupported reaction.
Derivation of a New Compounding Ingredient for Rubber from Waste Marble Powder and Study on its Suitability in an Innerliner Compound of Tubeless Tyres
Authors: Dasgupta Mridul , Gupta Saikat Das , Mukhopadhyay Rabindra , Bandyopadhyay Abhijit
Published: September 2018

Marble powder is a hazardous byproduct of marble industries, which are abundant in the western part of India. It has limited outlets for reuse and is causing severe environmental pollution. An effort has been made to convert this waste marble powder to a useful ingredient for rubber compounds. Accordingly, a chemical treatment has been done to this marble powder and a new material has been derived which is composed of carbonates of mainly calcium and partly magnesium. This material is named as Treated Marble Powder (TMP). TMP is characterized using different analytical techniques and also, to have a comparison with the commercially available whiting (a filler of similar kind for rubber compounds), it is studied in a typical NR/CIIR based innerliner compound for tubeless tyres. Composition analysis reveals that TMP contains 83% calcium carbonate and 14% magnesium carbonate. Compared to raw marble powder and whiting, it has got higher surface area, which is achieved through the chemical treatment. It is also observed that this new material TMP provide some significant advantages to the innerliner compound over whiting, such as higher scorch safety and elongation at break and lower air permeability. Due to these benefits, TMP can be an effective alternative to whiting and by this way, it also generates a new avenue for reuse of waste marble powder to minimize the environmental pollution.
Evaluation of Accelerated Solvent Extraction (ASE) Followed by Post-condensation Step (SSP) to Extract Contaminants from PET Flakes
Authors: Santos Amélia S.F. , Baraldi Patricia T. , Medeiros Eliton S. , Agnelli José A.M. , Correa Arlene G. , Manrich Sati
Published: September 2018

Aiming to reduce the overall energy consumption of PET super-clean technologies, without using hazardous and large amounts of solvents, this work deals with accelerated solvent extraction followed by solid state polymerization (ASE-SSP) as an alternative way to decontaminate recycled PET for direct food contact applications. The main effects of the extraction ASE parameters (temperature, flow rate and pressure) in extraction efficiency of toluene and benzophenone, used as model contaminants, from PET were evaluated using a first-order fractional experimental design. Subsequently, PET chips were submitted to a SSP process to remove residual acetone, used as the extractor solvent, from PET. Extraction yield was quantified by gas chromatography with flame ionization detector (GC-FID). Results showed that the only parameter that affects negatively the decontamination process was an increase in temperature. Moreover, the SSP process helped to remove residual acetone from PET reaching decontamination levels as high as the FDA recommendations for direct food contact packaging.
Thermoplastic Elastomeric Blends Based on Waste Tires and Polyethylene: The Role of Rubber Particle Size
Authors: Hrdlička Zdeněk , Cebriá Pablo Martín Marín , Štefan Vít , Kuta Antonín
Published: September 2018

Recycling of scrapped tires has become an essential worldwide challenge. The preparation of soft plastics, or thermoplastic elastomers (TPEs), is one of many ways possible for this. Many researchers have prepared TPEs using rubber particles with dimensions 500 μm or more. However, we assume mechanical properties of the TPEs could be improved by using rubber powder with smaller particles. Therefore, we studied the influence of six rubber powder fractions (diameters ranging from 120 to 500 μm) on mechanical properties of TPE samples prepared by blending of ground waste tire rubber (GTR) with low-density polyethylene (PE-LD) in the laboratory mixer (Brabender Plastograph). In addition, two adhesion components were applied: ethylene-propylene-diene rubber (EPDM) and a styrene-ethylene/butylene-styrene copolymer (SEBS). The results of tensile tests suggest that the use of smaller particle sizes, together with the adhesion component, can produce TPEs with improved mechanical properties.
Thermal Study of the Selective Tread Disassembling Procedure of Different Waste Tires
Authors: Szöke-Kis Anita , Zsitvai Mihály , Rácz László , Solti Szabolcs , Mizsey Péter
Published: September 2018

The annual amount of waste tires is enormous and permanently on the increase. Since their structure resists both physical and chemical degradation, their appropriate processing is an environmentally important subject and it is still a current research topic despite of the already existing technologies e.g. pyrolysis, thermal utilization.

In our work, a novel selective physical separation technology of waste tires is developed, presented and investigated. The technology is based on our new disassembling machine that enables the selective separation of the tread material of any kind of tires apart from their other constituting materials. The separation is an automated cutting process and its thermal profile is examined with a thermal imaging camera to determine if the cutting process can be associated with any kind of thermal degradation of the tread material. It is also an aim to detect if a special construction material of high thermal resistance would be needed for the cutting device. The experimental results are analyzed with the help of special software and it is found that the temperature values of the tire and the disassembling device can be classified into four different thermal zones. It is also determined that our novel device can be applied for tire machining; no thermal degradation occurs during the process, and there is no need for special construction material for the novel cutting device.
Conductive Poly(epichlorhydrin)–Polyaniline Dodecylbenzenesulfonate [PECH-PAni.DBSA] Rubber Blends Prepared in Solution
Authors: Bakhtiarian Elaheh , Foot Peter J.S. , Tate Philip C. Miller
Published: September 2018

Blends of poly(epichlorhydrin) elastomer [PECH] and polyaniline dodecylbenzenesulfonate [PAni.DBSA], with electrical conductivities up to 6.4×10−7 S cm−1, have been prepared by solution mixing and casting. The solubility parameters were calculated and the most suitable solvent (tetrahydrofuran) was selected for mutual solubility between PAni.DBSA and the compatible elastomer poly(epichlorhydrin) [PECH].

Fourier-transform infrared (FT-IR) spectra of PECH-PAni.DBSA blends contained features of the spectra of the pure materials, but with significant peak shifts due to changing intermolecular interactions between the polymers. Thermal decomposition steps of the conductive blends were investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The thermal stabilities of the blends were dependent on the ratio of PAni. DBSA to PECH. The electrical conductivities of blends with proportions of 1 to 50 wt% PAni.DBSA were measured by 2-probe and 4-probe techniques. The electrical conductivity increased with the proportion of PAni.DBSA, showing two percolation threshold stages, which were explained by a change in the conformation of the polymeric chains leading to an increase in the conductivity. The effects of composition on the glass transition in the blends were determined using thermomechanical analysis (TMA).
Effect of Carbon Black on the Properties of Polypropylene/ Recycled Natural Rubber Glove Blends
Authors: Hayeemasae Nabil , Ismail Hanafi , Khoon Tan Boon , Husseinsyah Salmah , Harahap Hamidah
Published: September 2018

In the present study, recycled natural rubber glove (rNRg) were used in an attempt to create a value-added thermoplastic elastomer material based on polypropylene/recycled natural rubber glove blends. Carbon black (CB) was also incorporated in a way to improve the mechanical properties to the blends. The blends were prepared in an internal mixer where the effects of CB loadings on processability, tensile properties, morphology and thermal stability of the blends were investigated. Results showed that the stabilization torque comparatively increases with the increment of the CB loading. Adding CB also improves the tensile strength and thermal stability to the blends. This is attributed to the better filler-matrix interaction and filler dispersion observed upon the incorporation of CB.
Flow Properties of Fly Ash Modified Asphaltic Binders
Authors: Mohamed Nazim , Ramjattan-Harry Vitra , Maharaj Rean
Published: September 2018

This paper investigated the influence of fly ash (FA) on the rheological properties of indigenous Trinidad asphaltic base binders: the world renowned Trinidad Lake Asphalt (TLA) and Trinidad Petroleum Bitumen (TPB). The intricate relationship between the chemical composition of the binder and its influence of the Fly ash additive was evident as changes in the phase angle, δ (a measure of elasticity) and the complex modulus, G* (a measure of stiffness) was not generalized but were different for the modified blends for each of the asphaltic base binders. Incremental additions of Fly ash (up to 8% wt.) to TLA and TPB resulted in a general increase in the complex modulus (G*) indicative of the stiffening of both materials: the stiffening effect being more significant with TLA compared to TPB. Incorporating incremental amounts of Fly ash to TLA resulted in a general decrease in the phase angle (δ): an increase in the elasticity of the blends. Incremental additions of Fly ash into TPB resulted in an opposite trend as the modified blends exhibited marginally decreasing elasticity (phase angle (δ) increasing). A significant finding of this study was the occurrence of a relatively stiffer and more elastic (high G* and low δ values) TLA blend containing 1% fly ash. The rheological property of loss modulus (G″) exceeded the storage modulus (G′) in all instances indicating that the asphaltic blends behaved like a viscoelastic liquid. This study has provided previously unavailable key information which can facilitate the creation of customized asphalt-Fly ash blends to suit special engineering applications thus offering an environmentally attractive option for improving the use of the world renowned TLA as well as refinery TPB.
Tensile and Impact Behaviour of Thermoplastic BOPP/Milk Pouches Blends Reinforced with Sisal Fibers
Authors: Rohit Kiran , Dixit Savita
Published: September 2018

Sisal (Agavae family) fiber reinforced BOPP/thermoplastic LLDPE: LDPE blend was prepared by melt mixing in a hydraulic compression press extruder. The composite were prepared with different fiber content: 5%, 10%, 15%, 20% (by weight). Mechanical properties (i.e. tensile strength and impact strength) were studied. Tensile strength showed an increasing trend with increase in fiber content up to 15% then decreases. Impact strength increases with the increase in fiber content. SEM shows the morphology and the melting point and material identification by DSC analysis.
An Evaluation of the Viscoelastic Performance of Polystyrene Modified Asphaltic Binders
Authors: Maharaj Rean , Ramlochan Demitri , Mohamed Nazim
Published: September 2018

The addition of waste Polystyrene to Trinidad Lake Asphalt (TLA) and Trinidad Petroleum Bitumen (TPB) resulted in variations in the rheological properties of the modified blends as measured by changes in the phase angle, δ (measure of the elasticity) and the complex modulus, G* (measure of the degree of stiffness). Since TLA and TPB produced significantly different and in some cases contrasting results, this study offered supporting evidence confirming that the influence of the waste PS on the rheological properties of asphaltic binders cannot be generalized as it varies due to differences in source and chemical composition of the parent binder. The incremental addition of PS to TLA resulted in a significant increase in G* (up to 1.5 times for 10% added PS at 1.59Hz loading frequency) indicative of the incremental stiffening of the TLA. Stiffening was more pronounced at higher frequencies and was greater for the TLA modified blends compared those of TPB. The addition of 10% PS to TPB resulted in G* increasing by 79.4%, most of this increase occurring after the addition of only 1% PS (56.5%). The addition of 10% PS to the TLA base binder resulted in the δ value decreasing to 10.6 degrees from 38.1 degrees signifying a significant increase in elasticity. The influence of PS on TPB on the other hand resulted in a generally insignificant decrease in elasticity as s the addition of 10% PS resulted in δ increasing to 88.8 degrees from 87.7 degrees remaining an almost viscous liquid. This study demonstrates the ability to produce PS modified TLA and TPB blends of differing rheological characteristics offering the potential creation of customized asphalt-PS blends to suit special applications. This study highlights the potential of the blending of waste PS into asphalt as an environmentally attractive option for solving waste disposal issues.
Investigating Effect of Chrome Tanned Leather Scraps in Ethylene Propylene Diene Monomer Rubber
Authors: Meşe Pınar , Karaağaç Bağdagül , Uyanık Nurseli
Published: September 2018

Nowadays, amount of chrome tanned leather scraps (CTL) of leather industry is increasing rapidly due to decreasing interest on CTL utilization in related areas. These kind of wastes cause considerable negative environmental effects and therefore CTL producers should find new recycling and/or disposing routes for them. It is speculated that CTL may be a valuable additive in rubber based materials thanks to its similar bending properties. In this study, it is aimed to evaluate rheological, thermal, mechanical, morphological, and aging properties of CTL loaded EPDM based rubber compounds. CTL wastes are incorporated into EPDM in various ratios by using a banbury mixer and two roll mill, subsequently. Rheological measurements show that CTL incorporation does not cause considerable losses in compound properties. Higher glass transition temperatures of CTL containing composites are attributed to restricted chain mobility of EPDM in the composites. Cheap CTL incorporation significantly improves the tear resistance of EPDM before and after thermal aging due to fibrous nature of leather.
Modification of Physical, Mechanical and Electrical Properties of Reinforced Epoxy Phenol Novolac with Nano Cobalt Acrylate and Carbon Nanotubes
Authors: Goudarzian N. , Amini P. , Mousavi S.M. , Hashemi S.A.
Published: September 2018

The research associated with optimal manufacturing procedure for composites strengthened with carbon nanotubes has became an important stage inside the early levels of discovery of fantastic physical properties of carbon nanotubes. The particular increasing interest has been brought by swift developments in nanotechnology and composites production techniques. This particular document brings together a study of two processes for production reinforced epoxy phenol novolak (EPN) with multi wall carbon nanotubes (MWCNT) and nano cobalt acrylate and evaluation of their physical properties. Shear mixing method and solution process are techniques that were used to produce plates and thin films of composites containing different weight fractions of unpurified and purified multiwall nanotubes. The first method consist in processing the pure combination of (EPN) and nanotubes in a reactor and the subsequent technique utilizes ultrasound to improve dispersion of nanotubes in the matrix through solvent medium. In this case, solution process showed a better dispersion of the encouragement in the matrix, but physical qualities did not show significant improvements. Mechanical qualities, for instance tensile strength, Young's modulus, fracture toughness, and hardness do not show relevant improvements. The explanation for this behavior is the poor adhesion at the interface carbon nanotube-matrix, attributable to tendency of MWNTs to agglomerate into bundles, which generate discontinuities in the last composite. The electrical Conductivity measurements indicate a percolating network formed only by inner metallic tubes of the nano composite.
Food & Fitness: Lessons Learned for Funders
Authors: Zurcher Kathleen A. , Doctor Linda Jo , Imig Gail L.
Published: September 2018

Communities face issues that are complex, affect diverse stakeholders who hold conflicting perspectives, involve historical systems, and have long delays between the time action is taken and results of the actions become obvious. In order to improve outcomes some funders have begun to shift their priorities to support systems change, rather than activities or programs that address discrete short-term needs and problems. In 2007, W.K. Kellogg Foundation funded Food & Fitness, a 9-year initiative designed to address the then-emerging concerns about childhood obesity and health inequities from a system perspective. Funded partnerships in communities with inequities across the United States created community-based approaches to increase access to locally grown food and healthy places for physical activity. This 9-year systems change initiative provided a unique opportunity to document lessons that can inform funders and communities seeking to create places that will support the health of children and families, as well as those leading other systems change initiatives.
Multiparametric High-Resolution MRI as a Tool for Mapping of Hypoxic Level in Tumors
Authors: Serša Igor , Bajd Franci , Savarin Monika , Jesenko Tanja , Čemažar Maja , Serša Gregor
Published: September 2018

Hypoxia is a condition, common to most malignant tumors, where oxygen tension in the tissue is below the physiological level. Among consequences of tumor hypoxia is also altered cancer cell metabolism that contributes to cancer therapy resistance. Therefore, precise assessment of tumor hypoxia is important for monitoring the tumor treatment progression. In this study, we propose a simple model for prediction of hypoxic level in tumors based on multiparametric magnetic resonance imaging. The study was performed on B16F1 murine melanoma tumors ex vivo that were first magnetic resonance scanned and then analyzed for hypoxic level using hypoxia-inducable factor 1-alpha antibody staining. Each tumor was analyzed in identical sections and in identical regions of interest for pairs of hypoxic level and magnetic resonance values (apparent diffusion coefficient and T2). This was followed by correlation analysis between hypoxic level and respective magnetic resonance values. A moderate correlation was found between hypoxic level and apparent diffusion coefficient (ρ = 0.56, P < .00001) and lower between hypoxic level and T2 (ρ = 0.38, P < .00001). The data were analyzed further to obtain simple predictive models based on the multiple linear regression analysis of the measured hypoxic level (dependent variable) and apparent diffusion coefficient and T2 (independent variables). Among the hypoxic level models, the most efficient was the 3-parameter model given by relation ( HL = kADC ADC + kT2 T2 + b), where kADC = 26%/µm2/ms, kT2 = 0.8%/ms, and b = −32%. The model can be used for calculation of the predicted hypoxic level map based on magnetic resonance–measured apparent diffusion coefficient and T2 maps. Similar prediction models, based on tumor apparent diffusion coefficient and T2 maps, can be done also for other tumor types in vivo and can therefore help in assessment of tumor treatment as well as to better understand the role of hypoxia in cancer progression.
Course of Social Participation in the First 2 Years After Stroke and Its Associations With Demographic and Stroke-Related Factors
Authors: Verberne Daan P. J. , Post Marcel W. M. , Köhler Sebastian , Carey Leeanne M. , Visser-Meily Johanna M. A. , van Heugten Caroline M.
Published: September 2018

Background. Many persons with stroke experience physical, cognitive, and emotional problems that contribute to restrictions in social participation. There is, however, a lack of knowledge on the long-term course of participation over time post-stroke. Objective. To describe the time course of participation up to 2 years post-stroke and to identify which demographic and stroke-related factors are associated with this time course. Methods. This was a multicenter, prospective cohort study following 390 persons with stroke from hospital admission up to 2 years (at 2, 6, 12, and 24 months). Multilevel modeling with linear and quadratic time effects was used to examine the course of the frequency of vocational and social/leisure activities, experienced restrictions, and satisfaction with participation. Results. The frequency of vocational activities increased up to 1 year post-stroke and leveled off thereafter. Older and lower-educated persons showed less favorable courses of participation than younger and higher-educated persons, respectively. The frequency of social/leisure activities decreased post-stroke. Participation restrictions declined up to 1 year post-stroke and leveled off thereafter. Persons dependent in activities of daily living (ADL) kept experiencing more restrictions throughout time than independent persons. Satisfaction with participation increased slightly over time. Conclusions. Changes in participation occurred mostly in the first year post-stroke. Particularly older and lower-educated persons, and those dependent in ADL showed less favorable courses of participation up to 2 years post-stroke. Clinicians can apply these findings in identifying persons most at risk of long-term unfavorable participation outcome and, thus, target rehabilitation programs accordingly.
Effect of Health-Promoting Agents on Exclusion-Zone Size
Authors: Sharma Abha , Adams Colby , Cashdollar Benjamin D. , Li Zheng , Nguyen Nam V. , Sai Himasri , Shi Jiachun , Velchuru Gautham , Zhu Kevin Z. , Pollack Gerald H.
Published: September 2018

It is now well-confirmed that hydrophilic surfaces including those within the cell generate structural changes in water. This interfacial water is ordered and acquires features different from the bulk. Amongst those features is the exclusion of colloidal and molecular solutes from extensive regions next to the hydrophilic surface, thereby earning it the label of “exclusion zone” (EZ) water. The transition of ordered EZ water to bulk serves as an important trigger of many cellular physiological functions, and in turn cellular health. We tested physiological doses of half a dozen agents generally identified to restore or build health on the extent to which they build EZs. All agents known to enhance biological function resulted in EZ expansion. On the other hand, the weed killer, glyphosate, considerably diminished EZ size. While the expansion effect of the health-promoting agents was observed over a wide range of concentrations, excessive doses ultimately reduced EZ size. We hypothesize that EZ buildup may be a mechanistic feature underlying many health-promoting agents, while agents that impair health may act by diminishing the amount of EZ water.
Histone deacetylase inhibitors prevent persistent hypersensitivity in an orofacial neuropathic pain model
Authors: Danaher Robert J , Zhang Liping , Donley Connor J , Laungani Nashwin A , Hui S Elise , Miller Craig S , Westlund Karin N
Published: September 2018

Chronic orofacial pain is a significant health problem requiring identification of regulating processes. Involvement of epigenetic modifications that is reported for hindlimb neuropathic pain experimental models, however, is less well studied in cranial nerve pain models. Three independent observations reported here are the (1) epigenetic profile in mouse trigeminal ganglia (TG) after trigeminal inflammatory compression (TIC) nerve injury mouse model determined by gene expression microarray, (2) H3K9 acetylation pattern in TG by immunohistochemistry, and (3) efficacy of histone deacetylase (HDAC) inhibitors to attenuate development of hypersensitivity. After TIC injury, ipsilateral whisker pad mechanical sensitization develops by day 3 and persists well beyond day 21 in contrast to sham surgery. Global acetylation of H3K9 decreases at day 21 in ipsilateral TG . Thirty-four genes are significantly ( p < 0.05) overexpressed in the ipsilateral TG by at least two-fold at either 3 or 21 days post-trigeminal inflammatory compression injury. The three genes most overexpressed three days post-trigeminal inflammatory compression nerve injury are nerve regeneration-associated gene ATF3, up 6.8-fold, and two of its regeneration-associated gene effector genes, Sprr1a and Gal, up 174- and 25-fold, respectively. Although transcription levels of 25 of 32 genes significantly overexpressed three days post-trigeminal inflammatory compression return to constitutive levels by day 21, these three regeneration-associated genes remain significantly overexpressed at the later time point. On day 21, when tissues are healed, other differentially expressed genes include 39 of the top 50 upregulated and downregulated genes. Remarkably, preemptive manipulation of gene expression with two HDAC inhibitors (HDACi's), suberanilohydroxamic acid (SAHA) and MS-275, reduces the magnitude and duration of whisker pad mechanical hypersensitivity and prevents the development of a persistent pain state. These findings suggest that trigeminal nerve injury leads to epigenetic modifications favoring overexpression of genes involved in nerve regeneration and that maintaining transcriptional homeostasis with epigenetic modifying drugs could help prevent the development of persistent pain.
Diffusion-weighted imaging lesion growth occurs despite recanalization in acute ischemic stroke: Implications for future treatment trials
Authors: Sah Rani G , d’Esterre Christopher D , Hill Michael D , Hafeez Moiz , Tariq Sana , Forkert Nils D , Frayne Richard , Demchuk Andrew M , Goyal Mayank , Barber Philip A
Published: September 2018

Background

A proportion of patients presenting with acute small ischemic strokes have poor functional outcomes, even following rapid recanalization treatment.

Aims

Infarct growth may occur even after successful recanalization and could represent an appropriate endpoint for future stroke therapy trials.

Methods

Magnetic resonance diffusion-weighted imaging lesion volumes were obtained at 5 h (initial posttreatment) and 24 h (follow-up) after acute stroke treatment for n = 33 in ischemic stroke patients. Sample sizes per arm (90% power, 30% effect size) for diffusion-weighted imaging lesion growth between initial and 24 h, early change in the National Institutes of Health Stroke Scale between pre- and 24 h, National Institutes of Health Stroke Scale at 24 h, and diffusion-weighted imaging lesion volume at 24 h were estimated to power a placebo-controlled stroke therapy trial.

Results

For patients with poor recanalization (modified thrombolysis in cerebral infarction <2 a; modified arterial occlusion lesion = 0–2) (n = 11), the median diffusion-weighted imaging lesion growth was 8.1 (interquartile range: 4.5, 22.4) ml and with good recanalization (modified thrombolysis in cerebral infarction =2 b or 3; modified arterial occlusion lesion = 3) (n = 22), the median diffusion-weighted imaging lesion growth was 10.0 (interquartile range: 6.0, 28.2) ml ( P = 0.749). When considering a 30% effect size, the sample size required per arm to achieve significance in an acute stroke study would be: (1) N = 49 for the diffusion-weighted imaging lesion growth between initial posttreatment and follow-up time points, (2) N = 65 for the change in the National Institutes of Health Stroke Scale between admission and 24 h, (3) N = 259 for the National Institutes of Health Stroke Scale at 24 h, and (4) N = 256 for diffusion-weighted imaging volume at 24 h.

Conclusion

Despite best efforts to recanalize the ischemic brain, early diffusion-weighted imaging lesion growth still occurs. Treatment trials in stroke should consider early diffusion-weighted imaging lesion growth as a surrogate outcome measure to significantly reduce sample sizes.
Gear selection between techniques in freestyle cross-country skiing in athletes with intellectual impairment: A pilot study
Authors: Blomqvist Sven , Van Biesen Debbie , Vanlandewijck Yves
Published: September 2018

Cross-country skiing is a fast-paced, a cognitively demanding, and a popular sport within international organizations including athletes with intellectual impairment (II); however, research on how the level of II affects skiing performance is limited. The aim of this exploratory study was to compare differences in the overall performance (segment time and race time) and gear selection between a sample of cross-country skiers with II ( n = 22) and a control group of skiers without II ( n = 12), during a competitive 10 km freestyle race. The groups were matched on training background and skiing level based on interviews with coaches and trainers. The independent samples t-test revealed a higher velocity in the first segment for the control group (6.10 ± 0.62 m/s) compared to the skiers with II (5.50 ± 0.56 m/s; p < 0.05), but no significant differences in total race time between the groups. With respect to their ability to effectively select gears during the races, there was a significant difference between the groups, where the pattern was that skiers with II used a lower gear compared to the skiers without II and that pattern became even more apparent towards the second half of the race. These findings support the assumption that impaired cognitive function may constrain the ability to optimally select the appropriate gear in function of the characteristics of the skiing track, which is a key determinant of skiing performance.
The Bernhardt of Scandinavia: Betty Nansen’s Modern Breakthrough
Authors: Adriaensens Vito
Published: September 2018

The cinema of the 1910s witnessed the birth of the film star, modelled after theatrical strategies that were spearheaded by actresses of international renown such as Sarah Bernhardt. She can be seen to have given birth to the notion of ‘famous players in famous plays’ in 1912, though in Denmark, the influential Nordisk Films Kompagni had already invested more extensively in marketing the appeal of theatrical stars that crossed over into the realm of film by this time. I will trace how Nordic drama was marketed internationally by analysing the trajectory of one of the most important, yet undervalued, actresses of the time, Betty Nansen (1873–1943) – also known as the Bernhardt of Scandinavia. Nansen was the model for the new ‘post-Ibsen’ female in Scandinavian society, both on and off the stage, and additionally a key example of how theatre and film uniquely managed to bridge the gap in Denmark. Betty Nansen’s stage and screen work reinforced each other, from the Danish Royal Theatre to the American Fox Film Corporation, and to managing her own theatre in Copenhagen, the still extant Betty Nansen Teatret.
Hand and wrist joint procedures in patients with scleroderma: a systematic review
Authors: Politikou Olga , Giesen Thomas , Reissner Lisa , Calcagni Maurizio
Published: September 2018

We aimed to examine if joint procedures in hands and wrists of patients with scleroderma could be performed without major morbidity and conducted a systematic review of the literature to assess this hypothesis. Studies were identified in four different databases; soft tissue procedures in scleroderma patients were excluded, and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Seven studies out of an initial total of 203 articles were included. One-hundred and twelve scleroderma patients with a total of 402 joint procedures in the hand and wrist were identified. A low complication incidence, comparable with that of non-sclerodermic population, in terms of infection, wound healing problems, and nonunion was reported in all studies. The application of joint procedures in scleroderma hands and wrists seems to be associated with low morbidity.
Analysis of the risk factors that determine composite graft survival for fingertip amputation
Authors: Eo SuRak , Doh GyeongHyeon , Lim SooA , Hong Ki Yong
Published: September 2018

The composite graft is the only surgical method that is able to maintain digital length and provide soft tissue coverage without donor site morbidities in microsurgically non-replantable fingertip amputations. This study aimed to explore the risk factors that determine the survival of composite grafts. Clinical characteristics associated with graft survival were retrospectively analysed by a comparison between the graft survival and failure groups. Of 94 patients who underwent a composite graft for fingertip amputation, the graft survived in 84 (89%). Surviving grafts showed reperfusion within 1 week. Multivariate analysis revealed that graft failure was independently associated with a crushing injury. Based on the risk factors from the comparison analyses and a review of previously published studies, a cutting injury, grafting the injured finger within 5 hours of injury, and being a non-smoker are associated with good results. In these circumstances, excellent outcomes with a high success rate can be achieved by composite graft in most adult patients as an alternative treatment to microsurgical replantation.

Level of evidence: IV