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Glass Rod (glass + rod)
Selected AbstractsSilicon Microstructures: Detachment Lithography of Photosensitive Polymers: A Route to Fabricating Three-Dimensional Structures (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 2 2010Mater. The scanning electron microscope image featured on the front cover shows a three-dimensional polydimethylsiloxane (PDMS) molded film bonded on a glass rod. Multilevel silicon structures used to mold the PDMS film were fabricated from successive steps of detachment lithography of photoresist films, which are patterned with lithography and reactive ion etching, as reported by J. Yeom and M. A. Shannon on page 289. The smallest feature on the pyramid is 2 µm in diameter. [source] Raman spectroscopy for spinline crystallinity measurements.JOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008Abstract The original Doufas,McHugh two-phase microstructural/constitutive model for stress-induced crystallization is expanded to polyolefin systems and validated for its predictive capability of online Raman crystallinity and spinline tension data for two Dow homopolymer polypropylene resins. The material parameters,inputs to the model,are obtained from laboratory-scale material characterization data, that is, oscillatory dynamic shear, rheotens (melt extensional rheology), and differential scanning calorimetry data. The same set of two stress-induced crystallization material/molecular parameters are capable of predicting the crystallinity profiles along the spinline and fiber tension very well overall for a variety of industrial fabrication conditions. The model is capable of predicting the freeze point, which is shown, for the first time, to correlate very well with the measured stick point (i.e., the point in the spinline at which the fiber bundle converts from a solid-like state to a liquid-like state and sticks to a solid object such as a glass rod). The model quantitatively captures the effects of the take-up speed, throughput, and melt flow rate on the crystallization rate of polypropylene due to stress-induced crystallization effects. This validated modeling approach has been used to guide fiber spinning for rapid product development. The original Doufas,McHugh stress-induced crystallization model is shown to be numerically robust for the simulation of steady polypropylene melt spinning over a wide range of processing conditions without issues of discontinuities due to the onset of the two-phase constitutive formulation downstream of the die face, at which crystallization more realistically begins. Because of the capturing of the physics of polypropylene fiber spinning and the very good model predictive power, the approximations of the original Doufas,McHugh model are asserted to be reasonable. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Perfume fingerprinting by easy ambient sonic-spray ionization mass spectrometry: nearly instantaneous typification and counterfeit detectionRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 22 2008Renato Haddad Perfume counterfeiting is an illegal worldwide practice that involves huge economic losses and potential consumer risk. EASI is a simple, easily performed and rapidly implemented desorption/ionization technique for ambient mass spectrometry (MS). Herein we demonstrate that EASI-MS allows nearly instantaneous perfume typification and counterfeit detection. Samples are simply sprayed onto a glass rod or paper surface and, after a few seconds of ambient drying, a profile of the most polar components of the perfume is acquired. These components provide unique and reproducible chemical signatures for authentic perfume samples. Counterfeiting is readily recognized since the exact set and relative proportions of the more polar chemicals, sometimes at low concentrations, are unknown or hard to reproduce by the counterfeiters and hence very distinct and variable EASI-MS profiles are observed for the counterfeit samples. Copyright © 2008 John Wiley & Sons, Ltd. [source] Spontaneous oscillation and mechanically induced calcium waves in chondrocytesCELL BIOCHEMISTRY AND FUNCTION, Issue 2 2006Taisuke Kono Abstract The characteristics of spontaneous calcium (Ca2+) oscillation and mechanically induced Ca2+ waves in articular chondrocytes were studied. In some, but not all, chondrocytes in sliced cartilage and primary cultures, we observed spontaneous oscillation of intracellular Ca2+ that never spread to adjacent cells. In contrast, a mechanical stimulus to a single cell by touching with a glass rod induced an increase of intracellular Ca2+ that spread to neighboring cells in a wave-like manner, even though there was no physical contact between the cells. This indicated the release of some paracrine factor from the mechanically stimulated cells. Application of ultrasonic vibration also induced an oscillation of intracellular Ca2+. The application of a uridine 5,-triphosphate (UTP), UTP, induced a transient increase in intracellular Ca2+ and the release of adenosine 5,-triphosphate (ATP) in cultured chondrocytes. A P2 receptor antagonist (suramin) and blockers of Cl, channels, niflumic acid and 4,4,-diisothiocyanostilbene-2,2,-disulfonic acid (DIDS), reduced the UTP-induced ATP release. The results indicated that Cl, channels were involved in the extracellular release of ATP following mechanical or P2Y receptor stimulation. Thus, ATP stimulation of P2Y receptors elicits an increase in intracellular Ca2+, triggering further release of ATP from adjacent cells, thereby expanding the Ca2+ wave in chondrocytes. Copyright © 2005 John Wiley & Sons, Ltd. [source] Polymerization stress, flow and dentine bond strength of two resin-based root canal sealersINTERNATIONAL ENDODONTIC JOURNAL, Issue 10 2009S. F. C. Souza Abstract Aim, To compare two resin-based root canal sealers (AH Plus and dual cure Epiphany) in terms of flow, polymerization stress and bond strength to dentine. Methodology, Flow was evaluated by measuring the diameter of uncured discs of sealer (0.5 mL) after 7 min compression (20N) between two glass plates (n = 5). Polymerization stress was monitored for 60 min in 1-mm thick discs bonded to two glass rods (Ø = 5 mm) attached to a universal testing machine (n = 3). Bond strength was analyzed through micropush-out test (n = 10) and failure mode was examined with scanning electron microscope (100× and 2500×). Data were statistically analyzed using the Student's t -test (, = 0.05). Results, Polymerization stress was 0.32 ± 0.07 MPa for Epiphany self-cure, 0.65 ± 0.08 MPa for Epiphany light-cure and zero for AH Plus (P < 0.05). Flow data and bond strength values were 30.9 ± 1.1, 28.6 ± 0.7 mm and 6.3 ± 5.3, 17.8 ± 7.5 MPa for Epiphany and AH Plus, respectively (P < 0.001). Failure mode was predominantly cohesive in the sealer for both materials. Conclusions, Epiphany had higher flow and polymerization stress and lower bond strength values to dentine than AH Plus. In view of these findings it can be implied that AH Plus would provide a better seal. [source] Effect of processing variables on texture development in a mica-based glass,ceramicJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2003I. L. Denry Abstract The purpose of this study was primarily to determine the feasibility of heat-pressing a mica-based glass,ceramic with the use of commercially available dental equipment, and secondly to evaluate the effect of various processing variables on the degree of crystal alignment in the pressed glass,ceramic. The hypotheses were that the mica-based glass,ceramic could be successfully heat-pressed and that some degree of crystal orientation would be obtained, depending on the processing variables. The glass composition was melted at 1400 °C for 2 h and cast into 12 × 60-mm rods. Ingots (10 × 12 mm) were cut from the glass rods, heat treated, and heat-pressed under various conditions. The microstructure of the pressed specimens was investigated by SEM and compared to that of heat-treated controls. The length of Vickers-induced cracks was measured on heat-pressed specimens and heat-treated controls. The results showed that mica-based glass-ceramics could be successfully pressed with the use of commercially available dental equipment. The resulting degree of crystal alignment (texture) along the direction of pressing varied between 35 ± 6 and 79 ± 6. There was a linear relationship between the degree of texture and the apparent aspect ratio of the mica platelets. A significant decrease in the length of the Vickers-induced cracks in the direction perpendicular to pressing was observed, associated with an increase in length in the direction of pressing. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 64B: 70,77, 2002 [source] | ||||||||||