bluuebunny/crossref_metadata_2025_split huggingface dataset:
ROLE OF MATERIAL COMPOSITION IN THE CONSTRUCTION OF VISCOELASTIC MASTER CURVES: SILICA-FILLER NETWORK EFFECTS
Authors: Maghami S. , Dierkes W. K. , Tolpekina T. V. , Schultz S. M. , Noordermeer J. W. M. 
Published: May 2013

ABSTRACT
One of the important aspects in the development of new tire compounds is the correlation between the dynamic mechanical properties of the rubber, measured on a laboratory scale, and the actual tire performance. The measuring protocol for dynamic mechanical properties with high precision and good correlation with tire properties is therefore of main concern. To predict wet traction, the viscoelastic behavior of the rubber materials at high frequencies (in the MHz range) need to be known. Viscoelastic master curves derived from time-temperature superposition can be used to describe the properties of the materials over a wide frequency range. The construction of master curves for tread compounds filled with different amounts of silica is discussed. From the vertical shifts as a function of temperature, activation energies are derived that apparently are in the linear response region by fulfilling the Kramers-Kronig relations, and their values correspond to physical phenomena as the underlying principle. Strain sweep viscoelastic measurements, per definition outside the linear region, lead to much higher activation energies. Because the deformation strains employed for these strain sweep measurements are more realistic for wet traction or skidding phenomena, it is concluded that the value of the above measurements in the linear region to predict traction is only limited or a first but still important indication.
COMPREHENSIVE NUMERICAL MODEL FOR THE INTERPRETATION OF CROSS-LINKING WITH PEROXIDES AND SULFUR: CHEMICAL MECHANISMS AND OPTIMAL VULCANIZATION OF REAL ITEMS
Authors: Milani Gabriele , Milani Federico 
Published: May 2013

ABSTRACT
This work presents a comprehensive numerical model to optimize mechanical properties of thick rubber vulcanized items, comprising medium and high voltage electric cables and three-dimensional devices. Several vulcanization systems are considered, including peroxides and accelerated sulfur. For peroxides, both a genetic algorithm (GA) and an alternating tangent (AT) approach are adopted to determine the optimal final mechanical properties (tensile strength) of rubber items. The use of a mixture of peroxides is also considered, demonstrating that balanced mixtures may help in reducing the curing time and/or in increasing the optimal tensile strength in both core and skin of thick devices. For sulfur vulcanization, a mathematical kinetic model is presented to predict the cross-linking density of vulcanized rubber. The model is conceived to fit experimental rheometer data, and it is suitable to have an estimate of cross-linking degree at fixed temperature. The model requires a parametric calibration by means of only three kinetic constants, successively implemented in Finite Element (FE) software, specifically developed to perform thermal analyses on two-dimensional geometries. As an example, an extruded cylindrical thick EPDM item is considered and meshed through four-noded isoparametric plane elements. Several FE simulations are repeated changing both exposition time, tc, and external curing temperature, Tc, to evaluate for each (tc, Tc) couple the corresponding mechanical properties of the item at the end of the thermal treatment.
MODIFICATION OF SKIM RUBBER BLENDED WITH POLY (VINYL ALCOHOL) TO BE APPLIED AS A BIODEGRADABLE PRESSURE-SENSITIVE ADHESIVE: EFFECT OF 2,6-DI-T-BUTYL-4-METHYLPHENOL AND HYDROCARBON RESIN
Authors: Riyajan Sa-Ad , Pheweaw Nataphon 
Published: May 2013

ABSTRACT
Pressure-sensitive adhesives (PSAs), or self-adhesives, are used in many applications, including safety labels for power equipment, automotive interior trim assembly, and sound/vibration–damping films. The objective of this study was to develop a biodegradable skim rubber–based bioadhesive blended with poly (vinyl alcohol) (PVA), which has the advantage of being biodegradable and biocompatible to humans. PSAs were produced from saponified low-protein skim rubber (S-LPSR) alone using a hydrocarbon resin as a tackifier and blends of S-LPSR/PVA containing tackifier, via solution and emulsion, respectively. The influence of 2,6-di-t-butyl-4-methylphenol (BHT) and the hydrocarbon resin content in the adhesive formulation was studied. Various methods were used to evaluate the properties of the adhesives produced including scanning electron microscopy, differential scanning calorimetry, contact angle measurement, dynamic mechanical thermal analysis, and Fourier transform infrared spectroscopy. The optimal concentration of PVA for a good PSA was found to be 20 phr because of its emulsion form. The adhesion properties of a PSA containing 50–60 phr of hydrocarbon resin and 1% BHT displayed excellent tack and peel compared with other samples because there was no chain scission of the skim rubber and good compatibility and interaction between the S-LPSR/PVA blend and the hydrocarbon resin, which maximized the adhesion properties of the adhesive.
ELASTOMER NANOCOMPOSITES BASED ON BR/EPDM/ORGANOCLAY
Authors: Kharazmkia M. , Naderi G. , Ghoreishy M. H. R. , Shokoohi S. 
Published: May 2013

ABSTRACT
Elastomer nanocomposites based on BR, EPDM, and Cloisite 15A were prepared via melt compounding on a laboratory scale two-roll mill. Effect of BR/EPDM composition ratio (0/100, 75/25, 50/50, 25/75, and 100/0) and nanoclay content (3, 5, 7, and 10 w/w) on the microstructure, mechanical, and rheological properties of BR/EPDM/organoclay nanocomposites were studied. Cure characterization results of the prepared elastomer nanocomposites are indicative of the accelerative role of nanoclay in the vulcanization reaction of matrix elastomer chains. The remarkable increase observed in the torque values as well as the increasing trend of gel contents represent the cross-link density increment at the presence of organoclay. Results of x-ray diffraction (XRD) analysis showed an increase in the d-spacing values associated with the silicate layers indicating the intercalation of matrix elastomer chains into the clay galleries. Transmission electron microscopy micrographs of nanocomposite samples depict an intercalated/partially exfoliated microstructure confirming XRD results. According to the measured mechanical pr7operties, incorporation of organo-modified montmorillonite improved the mechanical properties of BR/EPDM compounds. This could be ascribed to the establishment of interactions between silicate layers and polymer matrix that was evidenced by scanning electron microscopy photomicrographs and enhanced rheological properties.
THERMAL PROTECTION OF POLYAMIDE 6/ACRYLONITRILE–BUTADIENE RUBBER THERMOPLASTIC-VULCANIZATES: INFLUENCE OF TYPE AND CONTENT ON BLEND PROPERTIES
Authors: de Oliveira Gomes Ana Catarina , Gomes Oliveira Marcia , Marcio Paranhos Caio , Guenther Soares Bluma 
Published: May 2013

ABSTRACT
Polyamide 6 (PA6)/NBR blends are interesting because of their supposed properties at elevated temperatures. The blend, however, has a critical problem in terms of processing stability, as a result of the thermal degradation of the NBR phase. We evaluate a system of dissimilar addition of antioxidant in each phase (a combination of Irganox®/Irgafos® for the PA phase, and Naugard 445® for the NBR phase) and study the influence of these antioxidants on the properties of the blend. The evaluation was performed through tensile strength, differential scanning calorimetry (DSC), thermogravimetric analysis, and X-ray diffraction analysis. The influence of the antioxidant system on the crystallization process of the PA phase was evaluated through isothermal DSC analysis. Results showed the best combination of antioxidant addition in master batches and during processing.
MODIFIED GUTH–GOLD EQUATION FOR CARBON BLACK–FILLED RUBBERS
Authors: Fukahori Y. , Hon A. A. , Jha V. , Busfield J. J. C. 
Published: May 2013

ABSTRACT
The modulus increase in rubbers filled with solid particles is investigated in detail here using an approach known widely as the Guth–Gold equation. The Guth–Gold equation for the modulus increase at small strains was reexamined using six different species of carbon black (Printex, super abrasion furnace, intermediate SAF, high abrasion furnace, fine thermal, and medium thermal carbon blacks) together with model experiments using steel rods and carbon nanotubes. The Guth–Gold equation is only applicable to such systems where the mutual interaction between particles is very weak and thus they behave independently of each other. In real carbon black–filled rubbers, however, carbon particles or aggregates are connected to each other to form network structures, which can even conduct electricity when the filler volume fraction exceeds the percolation threshold. In the real systems, the modulus increase due to the rigid filler deviates from the Guth–Gold equation even at a small volume fraction of the filler of 0.05–0.1, the deviation being significantly greater at higher volume fractions. The authors propose a modified Guth–Gold equation for carbon black–filled rubbers by adding a third power of the volume fraction of the blacks to the equation, which shows a good agreement with the experimental modulus increase (G/G0) for six species of carbon black–filled rubbers, where G and G0 are the modulus of the filled and unfilled rubbers, respectively; ϕeff is the effective volume fraction; and S is the Brunauer, Emmett, Teller surface area of the blacks. The modified Guth–Gold equation indicates that the specific surface volume ()3 closely relates to the bound rubber surrounding the carbon particles, and therefore this governs the reinforcing structures and the level of the reinforcement in carbon black–filled rubbers.
HEAT BUILD-UP OF RUBBER UNDER CYCLIC LOADINGS: VALIDATION OF AN EFFICIENT DEMARCH TO PREDICT THE TEMPERATURE FIELDS
Authors: Le Saux V. , Marco Y. , Calloch S. , Charrier P. , Taveau D. 
Published: May 2013

ABSTRACT
Rubber-like materials exhibit a hysteretic behavior under cyclic loadings that, combined with a very low thermal conductivity, leads to a temperature rise called heat build-up in the literature. This phenomenon is especially crucial for antivibration parts that require both good fatigue resistance and high damping properties, involving a high dissipation under cyclic loading. Moreover, these parts exhibit complex shapes leading to complex local mechanical fields and therefore to thermal sources and temperature fields difficult to predict. To overcome the difficulties of the classical approach based on thermodynamically based models and to provide acceptable characterization and computation times for industrial needs, a simple phenomenological approach was previously suggested. We aim at validating this approach for several case studies. First, an identification procedure is proposed to identify efficiently the parameters of the thermal and mechanical problems, from a single test on an hourglass-shaped specimen. The validity of the identification step and of the modeling is then challenged by the confrontation of the numerical predictions to the results of an extended experimental database. The influences of the main influent factors are investigated (displacement amplitude, frequency, load ratio, sample volume) for tension and torsion tests on hourglass-shaped samples. The validity of the approach is asserted both on transient and stabilized temperature fields, for a temperature rise lower than 20 °C.
PREPARATION AND PROPERTIES OF STYRENE-BUTADIENE RUBBER/CLAY NANOCOMPOSITES BY USING LIQUID RUBBER/CLAY MASTER BATCHES
Authors: Fang Liang , Wei Ming , Warasitthinon Nuthathai , Shen Jia , Jian Rui , Schmidt Daniel , Barry Carol , Mead Joey 
Published: May 2013

ABSTRACT
Rubber/clay nanocomposites (RCNs) have many applications because of their improved properties. The dispersion of clay in a rubber matrix, which plays an important role in the properties of RCNs, is a challenge. In this article, a solvent-free approach to produce the styrene butadiene rubber (SBR)/clay nanocomposites by using liquid rubber/clay master batches was introduced. The liquid/rubber master batches were first prepared using a high-speed centrifugal mixer and then compounded with neat SBR using conventional rubber compounding equipment. Compared with the composites prepared by melt mixing, this approach resulted in a better dispersion of the clay in the rubber matrix and improvements in tensile strength (4.98 MPa at 10 phr clay loading) and elongation at break (&gt;1000% at 10 phr clay loading). The improved dispersion was confirmed by X-ray diffraction. The effect of clay loading on the tensile properties, dynamic mechanical properties, and the Payne effect was also investigated. The increase in clay loading resulted in a steady increase in the tensile properties up to a loading of 15 phr. The reinforcement in the RCN modulus using clay was compared with five models, including the Guth and Halpin-Tsai equations. This solvent-free approach offers benefits in dispersion of clay for industrial applications of rubber nanocomposites.
HYDROGENATED BUTADIENE-ACRYLONITRILE-BUTYLACRYLATE RUBBER AND ITS PROPERTIES
Authors: Yue Dongmei , Wei Xinpeng , Wang Xunzhang , Wang Weimin , Zhang Liqun 
Published: May 2013

ABSTRACT
Butadiene-acrylonitrile-butylacrylate rubber (BNBR), which is synthesized by copolymerization of butadiene, acrylonitrile, and butyl acrylate, retains excellent properties of oil resistance and heat resistance because of the introduction of -CN, -COOR in the polymer. However, the presence of a lot of carbon-carbon double bonds (-C=C-) could lead to deterioration of material properties such as thermal stability and ozone resistance. To improve the properties of unsaturated elastomers, further chemical modification of diene-based polymers is very critical. Hydrogenation is a useful chemical modification method that can improve the thermal stability of diene-based polymer. BNBR was hydrogenated by homogenous hydrogenation using the Wilkinson catalyst RhCl(PPh3)3 in xylene. The effects of catalyst concentrations, reaction times, and hydrogen pressures on the conversion and product selectivity were discussed. The degree of hydrogenation was measured by proton nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. The thermal stability of hydrogenated and nonhydrogenated copolymers was evaluated by thermogravimetric analysis (TGA). The CCD camera was used to characterize the ozone resistance of hydrogenated copolymer (HBNBR). The results obtained by TGA and the CCD camera show that the maximum saturation level is a critical factor for improvement of thermal stability and the ozone resistance of HBNBR.
Reversal of Pulmonary Hypertension after Diaphragm Pacing in an Adult Patient with Congenital Central Hypoventilation Syndrome
Authors: Morélot-Panzini Capucine , Gonzalez-Bermejo Jesus , Straus Christian , Similowski Thomas 
Published: May 2013

Introduction Patients with the congenital central hypoventilation syndrome (CCHS) suffer from life-threatening hypoventilation when asleep, making them dependent on mechanical ventilation (MV) at night or during naps. State-of-art respiratory management consists of intermittent positive-pressure ventilation via a tracheotomy or mask. In some patients hypoventilation is permanent, in which case ventilatory support must be extended to the waking hours. Diaphragm pacing can prove useful in such situations. Methods and Results This report describes the case of a 26-year-old woman with CCHS in whom failure to achieve adequate MV led to life-threatening pulmonary hypertension (PH), with a systolic pulmonary artery pressure (PAP) of 80 mmHg and right ventricular hypertrophy, despite optimization of all possible measures and despite extensive therapeutic education efforts. Diaphragm pacing using laparoscopically implanted intradiaphragmatic phrenic nerve stimulation electrodes corrected alveolar hypoventilation and lastingly reversed PH (systolic PAP below 40 mmHg after 2 months, sustained after 2 years). Diaphragm pacing induced shoulder pain, however, involving the chronic use of analgesics. The pacing had to be stopped for tolerance reasons after two years, leading to PH worsening and the need for diurnal MV. Conclusions Diaphragm pacing appears likely effective to restore alveolar ventilation and reverse PH in adult CCHS patients.
Mobile-Bearing Total Knee Arthroplasty: A Full Traumatic Rotation of 180°
Authors: Sudanese Alessandra , Castiello Emanuela , Affatato Saverio 
Published: May 2013

From February 2008 to September 2012 we implanted 204 mobile-bearing knee prostheses in 192 patients. All the prostheses were cemented (both femoral and tibial components), and the patella was not replaced. Only one early complication of the implants (1/204 = 0.004%) occurred after a traumatic event as a full 180° rotation of the mobile-bearing polyethylene insert. A 78-year-old woman presented with swelling and severe pain at her right knee. This traumatic event was the only case among our mobile-bearing insert patients. The failed polyethylene inserts were retrieved and studied using a scanning electron microscope (SEM, ZEISS EVO 50 EP, Cambridge, UK) operating at 20 kV. Scratching and pitting were found on the UHMWPE insert perpendicular to the machining tracks for the concave surface. SEM micrographs of the insert showed burnishing on the concave surfaces and longitudinal scratches were clearly detectable and well-marked on the analyzed surfaces. A traumatic, fully rotating, polyethylene insert is rare and our case is the first report describing a traumatic event with a complete 180 degree rotation mobile-bearing in a total knee prosthesis. In the literature few reports discuss clinical outcomes after total knee arthroplasty in patients with Parkinson's disease and they cite mixed results. However, some authors suggest that posterior-stabilized and cruciate-retaining TKA should work well while others prefer cruciate-retaining, condylar constrained kinetics, or hinged devices. Although we did not implant a posterior-stabilized mobile-bearing total knee prosthesis or a constrained prosthesis, we obtained good clinical and radiological results at the 2-year followup.
Adaptive control of an underactuated spherical robot with a dynamic stable equilibrium point using hierarchical sliding mode approach
Authors: Yue Ming , Liu Baoyin 
Published: May 2013

SUMMARYUnlike the traditional underactuated mechanical system, the equilibrium point of the inner swing‐up suspension of a spherical robot possesses stable and dynamic characteristics. The stable dynamic equilibrium position of the underactuated suspension must agree well with the uncertain rolling resistance in practice. To overcome this special underactuated problem with dynamic equilibrium, we present an adaptive control scheme to enhance the ground adaptability using hierarchical sliding mode approach. The control method can drive the spherical robot to a desired position, and at the same time, the suspension subsystem holds on their dynamic equilibrium points rapidly. The proposed control approaches are verified to be effective by numerical simulation for a spherical robot to achieve satisfactory control performances, such as ground adaptability, rapid convergence, and disturbance rejection. Copyright © 2013 John Wiley & Sons, Ltd.
Sensory Arrays of Covalently Functionalized Single‐Walled Carbon Nanotubes for Explosive Detection
Authors: Schnorr Jan M. , van der Zwaag Daan , Walish Joseph J. , Weizmann Yossi , Swager Timothy M. 
Published: May 2013

AbstractChemiresistive sensor arrays for cyclohexanone and nitromethane are fabricated using single‐walled carbon nanotubes (SWCNTs) that are covalently functionalized with urea, thiourea, and squaramide containing selector units. Based on initial sensing results and 1H NMR binding studies, the most promising selectors are chosen and further optimized. These optimized selectors are attached to SWCNTs and simultaneously tested in a sensor array. The sensors show a very high level of reproducibility between measurements with the same sensor and across different sensors of the same type. Furthermore, the sensors show promising long‐term stability, which renders them suitable for practical applications.
Efficient Delivery of p53 and Cytochrome C by Supramolecular Assembly of a Dendritic Multi‐Domain Delivery System
Authors: Ng David Yuen Wah , Fahrer Jörg , Wu Yuzhou , Eisele Klaus , Kuan Seah Ling , Barth Holger , Weil Tanja 
Published: May 2013

AbstractVersatile nanocarrier systems facilitating uptake of exogenous proteins are highly alluring in evaluating these proteins for therapeutic applications. The self‐assembly of an efficient nano‐sized protein transporter consisting of three different entities is presented: A streptavidin protein core functioning as an adapter, second generation polyamidoamine dendrons for facilitating cell uptake as well as two different therapeutic proteins (tumor suppressor p53 or pro‐apoptotic cytochrome c as cargo). Well‐defined dendrons containing a biotin core are prepared and display no cytotoxic behavior upon conjugation to streptavidin. The integration of biotinylated human recombinant p53 (B‐p53) into the three component system allows excellent internalization into HeLa, A549 and SaOS osteosarcoma cells monitored via confocal microscopy, immunoblot analysis and co‐localization studies. In addition, the conjugation of B‐p53 to dendronized streptavidin preserves its specific DNA‐binding in vitro, and its delivery into SaOS cells impairs cell viability with concomitant activation of caspases 3 and 7. The versatility of this system is further exhibited by the significant enhancement of the pro‐apoptotic effects of internalized cytochrome c which is analyzed by flow cytometry and cell viability assays. These results demonstrate that the “bio‐click” self‐assembly of biotinylated dendrons and proteins on a streptavidin adapter yields a stable supramolecular complex. This efficient bionanotransporter provides an attractive platform for mediating the delivery of functional proteins of interest into living mammalian cells in a facile and rapid way.
A Novel Preparation Method for Octreotide Acetate–Loaded PLGA Microspheres with a High Drug‐Loading Capacity and a Low Initial Burst Release, and Its Studies on Relations between In Vitro and In Vivo Release
Authors: Chen Bin , Han Bing , Song Liping , Xu Dan , Pei Jin 
Published: May 2013

ABSTRACTIn this study, octreotide acetate (OTA)–loaded poly(lactide‐co‐glycolide) (PLGA) microspheres were prepared using an optimized double emulsion solvent evaporation method. The loading capacity (LC) was increased by raising the concentration of OTA in the inner aqueous phase (W1), and burst release was decreased (<10.0%) because the higher viscosity hindered the diffusion of OTA. The in vitro release profiles were closely correlated with in vivo release profiles calculated using the Wagner–Nelson method (r = 0.9876). To evaluate the drug release profiles rapidly, an accelerated release method was developed. In the accelerated release method, the acidic and alkaline buffers (the first 6 h, pH 4.0; the last 18 h, pH 9.6) were used as release media, respectively. Results indicated that the accelerated release profiles (24 h) were closely correlated with the in vivo release profiles (r = 0.9623). Therefore, through optimization of the experiment variables (buffer components and pH), an accelerated release method was developed to evaluate in vivo drug release from microspheres. © 2013 Wiley Periodicals, Inc. Adv Polym Technol 2013, 32, 21354; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21354