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This paper considers a scan method to measure mechanical stresses for a photoelastic material by the value of the reflection coefficient difference of orthogonal linearly polarized light waves. The results of the estimation of the stress state of a poly(methyl methacrylate) sample using the proposed reflective method are described. The dependencies of change induced by stress birefringence in the stressed sample from the displacement of the measuring beam transverse to the compression axis and along the axis are given. The case of almost normal incidence of light is considered. [ABSTRACT FROM AUTHOR]

The polymerization of 2,3,4,5,6‐pentafluorobenzyl 2‐diazoacetate is conducted at ambient temperature and catalyzed by [(l‐prolinate)RhI(1,5‐dimethyl‐1,5‐cyclooctadiene)] or [(l‐prolinate)RhI(1,5‐cyclooctadiene)] yielding C1 polymers with molecular weights of 3000–4000 g mol−1 and dispersity between 1.1 and 1.3. Incorporation of the pentafluorobenzyl group into the C1 polymer results in a different solubility when compare to its C2 analog poly(2,3,4,5,6‐pentafluorobenzyl methacrylate). Efficient postmodifications via para‐fluoro‐thiol reaction with different thiols are conducted with this C1 polymethylene. [ABSTRACT FROM AUTHOR]

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An experimental investigation was conducted to study the effect of branch channel diameters on phase distribution behaviors of the two-phase flow in horizontal microimpacting T-junctions. The cross-section of the inlet channel was 1000 μm × 500 μm and the cross-sections of the branch channels were 400 μm × 500 μm, 600 μm × 500 μm, 800 μm × 500 μm, respectively. Nitrogen and pure water at 120 kPa (abs) and 25 °C were selected as the working fluids. A high speed recording camera was used to clarify the fluid dynamics of the gas–liquid two-phase flow in the test section. Combining above experimental results with the visualization data, the force mechanism of gas–liquid two-phase flow in microimpacting T-junction was analyzed. For the better application of microimpacting T-junctions, the separation efficiency was introduced to evaluate the separation effect. It was found that the uniformity of the phase distribution can be well improved with the decrease of the branch channel diameters. The influencing degree (I) on slug-annular flow was larger than that on slug flow and annular flow. Furthermore, the influencing degree (I) decreased as the superficial velocities of two phases increased when inlet was slug flow or annular flow. [ABSTRACT FROM AUTHOR]

An integrated platform consisting of a microfluidic paper-based/PMMA (Polymethyl-Methacrylate) chip and a small battery-operated detection system is proposed for the concentration detection of sulfur dioxide (SO 2 ). In the proposed method, a small strip of filter paper is coated with acid-base indicator and then inserted into a PMMA microchip. The SO 2 sample is then injected into the reservoir of the chip; prompting a reaction with the acid-base indicator. The chip is transferred to the detection system, where the reaction-induced color change is captured by a CMOS (Complementary Metal-Oxide Semiconductor) camera. Finally, the CMOS image is transferred to a cell phone via a USB (Universal Serial Bus) connector and the SO 2 concentration is derived using self-written RGB color analysis software. The experimental results obtained for 10 control samples show that the correlation coefficient for the variation of the R(ed) signal intensity with the SO 2 concentration is equal to R 2 = 0.9971 in the low-concentration range (20 ∼ 600 ppm) and R 2 = 0.9920 in the high-concentration range (600 ∼ 5000 ppm). The real-world applicability of the proposed platform is demonstrated by measuring the SO 2 concentrations of fifteen commercial food samples. The concentration measurements deviate by no more than 4.29% from those obtained using a standard macroscale technique. Overall, the results presented in this study show that the proposed integrated microfluidic paper-based system provides a cheap, compact and reliable method for SO 2 concentration measurement purposes. [ABSTRACT FROM AUTHOR]

The replacement of conventional graphite with high-performance turbostratic carbons has attracted tremendous interests for lithium ion batteries (LIBs). Herein, a facile and efficient self-sacrifice strategy is smartly developed to fabricate the nitrogen-doped porous carbon microtubes (NPCMs) by the carbonization of polypyrrole (PPY) functionalized electrospun polymethyl methacrylate (PMMA) microfiber template. The key point of this strategy is the choice of self-sacrifice PMMA template, which can be evaporated at relatively low temperatures. After the calcination, the NPCMs with different nitrogen binding configurations, such as pyridinic-N, pyrrolic-N and graphitic-N, are derived from PPY accordingly. Benefiting from the appealing structural features, the NPCMs exhibit desirable electrochemical performance, including a high reversible capacity (877.3 mAh g −1 at 0.05 A g −1 ), excellent rate capability (251.1 mAh g −1 at 5 A g −1 ) and good cycling stability (655.1 mAh g −1 with 83.7% retention after 400 cycles at 0.1 A g −1 ). This strategy might open new avenues for the design of a series of heteroatom-doped carbon materials in different application fields. [ABSTRACT FROM AUTHOR]

Cranial defects occur most commonly as a sequelae to trauma, the incidence being as high as 70%. The successful management of a case of trauma in an emergency situation requires quick evacuation of the hematoma, repair of the dura, and the scalp but not necessarily the integrity of the calvarial segment as an immediate measure. So the reconstruction of the calvarial defect in these cases is mostly carried out as a secondary procedure. Various materials are used for reconstruction of cranial defects, polymethyl methacrylate (PMMA) resin being one of them. In this article, we report a case which was successfully treated by PMMA resin in combination with a titanium mesh for reconstruction of the cranial defect as a secondary procedure. [ABSTRACT FROM AUTHOR]

The water structure and platelet compatibility of poly(methyl methacrylate (MMA)-block-2-hydroxyethyl methacrylate (HEMA)) were investigated. The molecular weight (Mn) of the polyHEMA segment was kept constant (average: 9600), while the Mn of the polyMMA segment was varied from 1340 to 7390. The equilibrium water content of the copolymers was found to be mainly governed by the HEMA content. The water structure in the copolymers was characterized in terms of the amounts of non-freezing and freezing water (abbreviated asWnfandWfz, respectively) using differential scanning calorimetry. It was found that theWnffor the copolymers were higher than those estimated from theWnffor the HEMA and MMA homopolymers and that the amount of excess non-freezing water depended on the polyMMA segment length. In addition, X-ray diffraction analysis revealed that some of the copolymers had cold-crystallizable water. These facts suggested that the polyMMA segments were involved in determining the water structures in the copolymers. Furthermore, the platelet compatibility of the copolymers was improved as compared to that of the HEMA homopolymer. It was therefore concluded that the platelet compatibility of the copolymer was related to the amount of excess non-freezing water. [ABSTRACT FROM PUBLISHER]

In this study, poly (methyl methacrylate–glycidyl methacrylate) [poly(MMA-GMA)] cryogels were prepared by radical cryocopolymerization of MMA with GMA as a functional comonomer. Reactive Green 19 dye was then attached to the cryogel by nucleophilic substitution reaction, and this dye-attached cryogel column was used for lysozyme adsorption. Characterization of the cryogel was performed by Fourier transform infrared spectroscopy, environmental scanning electron microscopy, Brunauer–Emmett–Teller, and energy dispersive X-ray analysis. Pore size of the cryogels was 15–30 μm and pores were interconnected structure. Attached amount of Reactive Green 19 to cryogel support was calculated as 106.25 μmol/g cryogel. Lysozyme adsorption studies were carried out by using a continuous system. It was found that the maximum amount of lysozyme adsorption (32 mg/g cryogel) obtained from experimental results was found to be approximately same with the calculated Langmuir adsorption capacity (33 mg/g cryogel). Desorption of adsorbed lysozyme was carried out by using 1.5 M NaCl in pH 4.5 acetate buffer, and desorption yield was found to be 97.4%. Cryogels were very stable, and it was found that there was no remarkable reduction in the adsorption capacity at the end of ten adsorption–desorption cycles. As a result, Reactive Green 19-attached cryogels have great advantages such as easy preparation, rapid adsorption, and desorption, being economic and allowing the direct separation of proteins. [ABSTRACT FROM AUTHOR]

Background Bone cements are used as adjuncts to fracture fixation methods and can also function as a local drug delivery system. The ability to elute drugs makes bone cement a promising and powerful chemotherapy treatment modality for osseous tumors. However, because of poor elution rates, the clinical application of this drug delivery mode remains challenging. Soluble fillers, such as sugars, salts, or biocompatible polymers, offer a solution to improve elution rates. This study quantified the effect of polyethylene glycol (PEG) on the elution properties of three commercially available bone cements. Methods Two grams of Vertebroplastic, Palacos, and Confidence bone cement powder containing three concentrations (0%, 20%, or 50%) of PEG filler were hand mixed with 10 mg of methotrexate. This powder mixture was then polymerized with 1.0 mL of the cement specific liquid monomer. The cylindrical elution samples were placed in saline solution and methotrexate elution was recorded for 720 h. Results The cumulative and daily elution rate increased as the concentration of PEG increased for each bone cement. However, the percent of increase depended on the bone cement used. Cumulative methotrexate elution increased by 40%-54% in case of the highest PEG filler concentration when compared with controls. Conclusions PEG soluble filler offers a promising method for improving methotrexate drug elution in bone cement. Future studies need to optimize the PEG and bone cement ratio that produces the greatest drug elution profile without sacrificing the biomechanical properties of bone cement. [ABSTRACT FROM AUTHOR]

Polymethyl methacrylate (PMMA) is one of the most popular synthetic polymers in aircraft windshields as an alternative to glass, due to its lightweight, high transparency and impact-resistant characteristics. The erosion behavior of PMMA is critical when used as an alternative to glass in an aircraft windshield. This paper presents experimental data on the effects of particle size, velocity and impingement angle on the roughness of PMMA, using 3D optical profilometry after solid particle erosion tests. Particular attention is paid to determining the different morphologies of imprints and cracks with regard to particle size, impact velocity and impingement angle. It is further shown that the removed volume in overlapping impacts measured by 3D profilometry is captured well. It is demonstrated that maximum erosion rate occurred at a 30° impingement angle and correlates well with the ductile erosion behavior of PMMA. Detailed worn surface analysis was performed using 3D optical profilometer scanning to investigate effects of particle size, velocity and impingement angle on the roughness of PMMA. [ABSTRACT FROM AUTHOR]

ABSTRACT Effect of titanium dioxide (TiO2) on morphology and mechanical properties of poly(vinylidene fluoride) (PVDF)/poly(methyl methacrylate) (PMMA) blend films prepared at different TiO2 contents by a melt casting process was studied. The results showed that tensile moduli in both the machine direction (MD) and the transverse direction (TD) increased with increasing TiO2 content, and calculated tensile moduli based on the Halpin-Tsai and the Kerner model were consistent with experimental ones in both the MD and TD of films containing 10 wt % TiO2. However, experimental tensile moduli exhibited smaller values compared with calculated ones, as the TiO2 content increased to 30 wt %, and it was assumed that this is due to the decrease of crystallinity of PVDF. Morphological observations indicated that TiO2 particles did not affect crystal structures of PVDF and the morphology of PVDF/PMMA amorphous phase, but hindered the crystallization of PVDF. The MD and TD elongation at break exhibited >200 and <20%, respectively. The SEM micrographs revealed that spherulites could deform along the MD when the tensile force was applied along the direction. By contrast, spherulites could not deform along the TD and fractured at very small elongation, owing to the anisotropic morphology of spherulites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40454. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this work is to evaluate the performance of the image acquisition chain of clinical full field digital mammography (FFDM) systems by quantifying their image quality, and how well the desired information is captured by the images. Methods: The authors present a practical methodology to evaluate FFDM using the task specific system-model-based Fourier Hotelling observer (SMFHO) signal to noise ratio (SNR), which evaluates the signal and noise transfer characteristics of FFDM systems in the presence of a uniform polymethyl methacrylate phantom that models the attenuation of a 6 cm thick 20/80 breast (20% glandular/80% adipose). The authors model the system performance using the generalized modulation transfer function, which accounts for scatter blur and focal spot unsharpness, and the generalized noise power spectrum, both estimated with the phantom placed in the field of view. Using the system model, the authors were able to estimate system detectability for a series of simulated disk signals with various diameters and thicknesses, quantified by a SMFHO SNR map. Contrast-detail (CD) curves were generated from the SNR map and adjusted using an estimate of the human observer efficiency, without performing time-consuming human reader studies. Using the SMFHO method the authors compared two FFDM systems, the GE Senographe DS and Hologic Selenia FFDM systems, which use indirect and direct detectors, respectively. Results: Even though the two FFDM systems have different resolutions, noise properties, detector technologies, and antiscatter grids, the authors found no significant difference between them in terms of detectability for a given signal detection task. The authors also compared the performance between the two image acquisition modes (fine view and standard) of the GE Senographe DS system, and concluded that there is no significant difference when evaluated by the SMFHO. The estimated human observer efficiency was 30 ± 5% when compared to the SMFHO. The results showed good agreement when compared to other model observers as well as previously published human observer data. Conclusions: This method generates CD curves from the SMFHO SNR that can be used as figures of merit for evaluating the image acquisition performance of clinical FFDM systems. It provides a way of creating an empirical model of the FFDM system that accounts for patient scatter, focal spot unsharpness, and detector blur. With the use of simulated signals, this method can predict system performance for a signal known exactly/background known exactly detection task with a limited number of images, therefore, it can be readily applied in a clinical environment. [ABSTRACT FROM AUTHOR]

Highlights: [•] PM-b-P(St-co-HEMA) was prepared via RAFT polymerization using AIBN/PM-CTA. [•] PM-b-P(St-co-HEMA-g-PCL) was prepared via ε-CL ROP initiated by PM-b-P(St-co-HEMA). [•] The M n, HEMA content and PCL content of such copolymers were well controllable. [•] Microporous PM-b-P(St-co-HEMA) films were fabricated via a static BF process. [•] Wrinkle-like morphology was formed in the case of PM-b-P(St-co-HEMA-g-PCL). [ABSTRACT FROM AUTHOR]

Highlights: [•] Siloxane–PMMA film was produced by dip-coating on tin plate substrate. [•] It was evaluated the influence of (TEOS) addition on siloxane–PMMA hybrid films. [•] Siloxane–PMMA films without TEOS presented a regular coverage and lowest roughness. [•] The TEOS addition decrease the corrosion resistance of siloxane–PMMA films. [•] Siloxane–PMMA without TEOS presented is higher durability in the film wear test. [Copyright &y& Elsevier]

Abstract: Three-dimensionally macroporous perovskite-type oxides EuFeO3 (EFO-3DOM, EFO-sucrose-1, EFO-sucrose-2, and EFO-sucrose-3, respectively) have been prepared using the polymethyl methacrylate-templating method in the absence or presence of sucrose. Physicochemical properties of the materials were characterized by means of a number of analytical techniques, and their catalytic activities were evaluated for the total oxidation of toluene. It is shown that all of the EFO samples were of single-phase orthorhombic crystal structure with a 3DOM architecture. The sucrose addition during the preparation process had a great effect on the surface area and porous structure of the final product. A clear correlation of surface area, surface oxygen species concentration, and low-temperature reducibility with the catalytic performance was observed. The EFO-sucrose-1 catalyst performed the best, giving the T 50% and T 90% of 312 and 347 °C at space velocity = 20,000 mL/(g h), respectively. The apparent activation energies of the 3DOM-structured EFO samples were in the range of 82–97 kJ/mol. It is concluded that the higher surface area and oxygen adspecies concentration and better low-temperature reducibility account for the good catalytic activity of EFO-sucrose-1. [Copyright &y& Elsevier]

This study has launched a concept to image a real-time 2D temperature distribution noninvasively by a combination of the electrical capacitance tomography (ECT) technique and a permittivity-temperature calibration equation for the plastic pellet cooling process. The concept has two steps, which are the relative permittivity calculation from the measured capacitance among the many electrodes by the ECT technique, and the temperature distribution imaging from the relative permittivity by the permittivity-temperature calibration equation. An ECT sensor with 12 electrodes was designed to image the cross-sectional temperature distribution during the polymethyl methacrylate pellets cooling process. The images of temperature distribution were successfully reconstructed from the relative permittivity distribution at every time step during the process. The images reasonably indicate the temperature diffusion in a 2D space and time within a 0.0065 and 0.0175 time-dependent temperature deviation, as compared to an analytical thermal conductance simulation and thermocouple measurement. [ABSTRACT FROM AUTHOR]