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Materials Used (material + used)
Kinds of Materials Used Selected AbstractsMultifunctional Mesoporous Silica Material Used for Detection and Adsorption of Cu2+ in Aqueous Solution and Biological Applications in vitro and in vivoADVANCED FUNCTIONAL MATERIALS, Issue 12 2010Qingtao Meng Abstract An inorganic,organic silica material (SBA,P2), prepared by immobilization of the 1,8-naphthalimide-based receptor P2 within the channels of the mesoporous silica material SBA-15, is characterized by transmission electron microscopy and several spectroscopic methods. SBA,P2 features a high affinity Cu2+ -specific fluorescence response in aqueous solution with a detection limit for Cu2+ of ca. 0.65,ppb (10,×,10,9,M) under optimized conditions. It can extract Cu2+ from the solution with only trace amounts remaining. Through isolating of the toxic ions within the mesopores of the silica, SBA,P2 has the potential to work as a toxicide for Cu2+ in living systems. The fluorogenical responses are reversible and do not vary over a broad (4.0 to 9.0) pH range suitable for application under physiological conditions. The fluorescence responses of Cu2+ in vitro (human breast cancer cells) and in vivo (five-day-old zebrafish) demonstrate the possibility of further application in biology. [source] The Influence of Magnetic Fields on the Mechanical Behaviour of Granular Materials Used for Foundry Moulding: Numerical and Experimental Analysis,ADVANCED ENGINEERING MATERIALS, Issue 8 2006P.-M. Geffroy Understanding the mechanical behaviour of granular materials is of financial importance in many industries, including the geotechnical [1], pharmaceutical and foundry sectors. In the latter, granular materials are used as mould elements for lost foam (sand) and magnetic moulding (steel shot) processes. This study focuses on optimising mould geometry and magnetic field characteristics (intensity and orientation) to obtain the desired dimensions of the final product. [source] Scanning Electron Microscope Analysis of Internal Adaptation of Materials Used for Pulp Protection under Composite Resin RestorationsJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 2 2005MARIA INEZ LEMOS PELIZ DDS ABSTRACT Purpose:: The aim of this study was to evaluate the interfacial microgap with different materials used for pulp protection. The null hypothesis tested was that the combination of calcium hydroxide, resin-modified glass ionomer, and dentin adhesive used as pulp protection in composite restorations would not result in a greater axial gap than that obtained with hybridization only. Materials and Methods: Standardized Class V preparations were performed in buccal and lingual surfaces of 60 caries-free, extracted human third molars. The prepared teeth were randomly assessed in six groups: (1) Single Bond (SB) (3M ESPE, St. Paul, MN, USA); (2) Life (LF) (Kerr Co., Romulus, MI, USA) + SB; (3) LF + Vitrebond (VT) (3M ESPE) + SB; (4) VT + SB; (5) SB + VT; (6) SB + VT + SB. They were restored with microhybrid composite resin Filtek Z250 (3M ESPE), according to the manufacturer's instructions. However, to groups 5 and 6, the dentin bonding adhesive was applied prior to the resin-modified glass ionomer. The specimens were then thermo-cycled, cross-sectioned through the center of the restoration, fixed, and processed for scanning electron microscopy. The specimens were mounted on stubs and sputter coated. The internal adaptation of the materials to the axial wall was analyzed under SEM with × 1,000 magnification. Results: The data obtained were analyzed with nonparametric tests (Kruskal-Wallis, p V .05). The null hypothesis was rejected. Calcium hydroxide and resin-modified glass ionomer applied alone or in conjunction with each other (p < .001) resulted in statistically wider microgaps than occurred when the dentin was only hybridized prior to the restoration. [source] Differing Expansion Contributions of Three Investment Materials Used for Casting TitaniumJOURNAL OF PROSTHODONTICS, Issue 5 2009Danny Low BDS, MScDent, MScMed Abstract Purpose: This laboratory study aimed at investigating the effect of setting expansion (SE), which could enlarge a wax pattern by concurrent exothermic reaction. Materials and Methods: Two phosphate-bonded investment materials (Rematitan Plus, T-invest C & B) and alumina-magnesia-based investment material (Titavest CB) were subjected to setting temperature and SE measurements (n = 10). Full-crown wax patterns were prepared from metal dies having the same design. Crown castings (n = 6) were made using a one-chamber high-pressure casting machine. Commercially pure titanium ingot (Japanese Industrial Standard Class II) was used for each casting. Dimensional accuracy of the cast crowns was expressed by marginal discrepancy for a pair of wax pattern and casting prepared from the same die. All results were then subjected to regression analysis. Results: Rematitan Plus gave the highest setting temperature (about 70°C) and the highest SE (1.16 ± 0.01%) almost concurrently. The result was that Rematitan Plus produced oversized crowns from the lowest thermal expansion (TE) value (0.53 ± 0.05%) reducing the linear correlation to 0.80 (p < 0.05). No significant linear relationship was found between SE of investment material and crown-casting accuracy. Conclusions: The almost concurrent occurrence of high SE and high setting temperature generation in Rematitan Plus enlarged the wax pattern and effectively supplemented its low TE to produce oversized crowns. Despite this adverse effect, the correlation between TE and crown accuracy was still high. It is generally expected that the TE values given by manufacturers predict crown accuracy, when uniform TE, small SE, and minimum heat generation during setting are assured. [source] Surface Composition of Materials Used as Catalysts for Methanol Steam Reforming: A Theoretical Study,CHEMPHYSCHEM, Issue 8 2006Kok Hwa Lim Dr. Abstract PdZn (1:1) alloy is assumed to be the active component of a promising catalyst for methanol steam reforming. Using density functional calculations on periodic supercell slab models, followed by atomistic thermodynamics modeling, we study the chemical composition of the surfaces PdZn(111) and, as a reference, Cu(111) in contact with water and hydrogen at conditions relevant to methanol steam reforming. For the two surfaces, we determine similar maximum adsorption energies for the dissociative adsorption of H2, O2, and the molecular adsorption of H2O. These reactions are calculated to be exothermic by about ,40, ,320, and ,20 kJ,mol,1, respectively. Using a thermodynamic analysis based on theoretically predicted adsorption energies and vibrational frequencies, we determine the most favorable surface compositions for given pressure windows. However, surface energy plots alone cannot provide quantitative information on individual coverages in a system of coupled adsorption reactions. To overcome this limitation, we employ a kinetic model, from which equilibrium surface coverages of H, O, OH, and H2O are derived. We also discuss the sensitivity of our results and the ensuing conclusions with regard to the model surfaces employed and the inaccuracies of our computational method. Our kinetic model predicts surfaces of both materials, PdZn and Cu, to be essentially adsorbate-free already from very low values of the partial pressure of H2. The model surfaces PdZn(111) and Cu(111) are predicted to be free of water-related adsorbates for a partial H2 pressure greater than 10,8 and 10,5 atm, respectively. [source] Materials used for root canal obturation: technical, biological and clinical testingENDODONTIC TOPICS, Issue 1 2005DAG ØRSTAVIK First page of article [source] Diagnosis and Management of Spontaneous Cerebrospinal Fluid-Middle Ear Effusion and Otorrhea,THE LARYNGOSCOPE, Issue 5 2004N. E. Brown MD Objectives/Hypothesis: Spontaneous leak of cerebrospinal fluid (CSF) into the middle ear can occur in adults without a history of temporal bone trauma or fracture, meningitis, or any obvious cause. Therefore, clues may be lacking that would alert the otolaryngologist that fluid medial to an intact eardrum, or fluid emanating from an eardrum perforation, is likely to be CSF fluid. A review of relevant medical literature reveals that herniation of the arachnoid membrane through a tegmen defect may be congenital, or CSF leak may occur when dynamic factors (i.e., brain pulsations or increases in intracranial pressure) produce a rent in the arachnoid membrane. Because tegmen defects may be multiple rather than single, identifying only one defect may not be sufficient for achieving definitive repair. Data on nine cases of spontaneous CSF leak to the ear in adult patients from four medical centers are presented and analyzed to provide collective information about a disorder that can be difficult to diagnose and manage. Study Design: Retrospective review of nine cases of spontaneous CSF middle ear effusion/otorrhea. Results: The majority of patients presented with symptoms of aural fullness and middle ear effusion. Many developed suspicious clear otorrhea only after insertion of a tympanostomy tube. Two patients had multiple defects in the tegmen and dura, and five patients had meningoencephaloceles confirmed intraoperatively. Five patients underwent combined middle cranial fossa/transmastoid repair. Materials used in repair included temporalis fascia, free muscle graft, Oxycel cotton, calvarial bone, pericranium, bone wax, and fibrin glue. Conclusions: CSF middle ear effusion/otorrhea can develop in adults without a prior history of meningitis or head trauma or any apparent proximate cause. Although presenting symptoms can be subtle, early suspicion and confirmatory imaging aid in establishing the diagnosis. Because surgical repair by way of a mastoid approach alone can be inadequate if there are multiple tegmen defects, a middle fossa approach alone, or in combination with a transmastoid approach, should be considered in most cases. [source] Growth and characterization of La3Ga5.5Ta0.5O14 crystalCRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2004Haikuan Kong Abstract La3Ga5.5Ta0.5O14 (LGT) crystal was grown by using the Czochralski method. The as-grown crystal is transparent, free from inclusions and with no cracks. Specific heat, thermal expansion, dielectric constants, transmission spectrum and optical damage threshold of LGT have been measured, and the results show general properties of LGT are similar to that of La3Ga5SiO14 (LGS) crystal. The experiment to research the Q-switch properties of LGT has been performed and the results show LGT possesses smaller electrooptic coefficients than that of LGS and may not be an ideal material used as a Q-switch. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Suppression of electromagnetic radiation noise from wireless modules in the millimeter-wave band by means of alumina containing carbon blackELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 10 2010Yasuharu Takase Abstract Unwanted electromagnetic (EM) radiation generated from wireless modules in the millimeter-wave band used for car radar creates errors and results in performance degradation of electronic equipment. In this paper, to reduce these unwanted EM waves, an optimal design to add the function of EM wave absorption to the lid for the module is examined. Alumina-containing carbon black is used as a wave absorption material for the lid. Absorption of 20 dB or more is obtained as a measured result with the cover added for EM wave absorption at 60 GHz. The wireless module was also analyzed in the millimeter-wave band with the designed material used for the lid. The radiation and the reflection of electric power were greatly reduced by the loss electric power from the lid. Therefore, effective data for suppressing unwanted EM radiation noise from wireless modules in the millimeter-wave band can be provided. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(10): 25,33, 2010; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.10216 3 [source] Selection of refractory for thermal oxidizers on gas streams containing fluorineENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 2 2002Stanley C. Che Thermal oxidizers for destruction of fluorine-containing chemicals are typically operated between 1,100° to 1,400° C. Fluorine is converted to hydrogen fluoride (HF) during the combustion process. At high temperatures, HF will react with almost all materials. Proper selection of the refractory material used by the thermal oxidizer is essential for long-term use, and to protect the metal shell from corrosion. Selection criteria should include analysis of chemical composition, physical properties, morphology, and bonding phases. A high alumina brick from a thermal oxidizer was analyzed after it had been in service for one year. The brick surface underwent significant changes of its chemical and micro-structural compositions. Silica in the mullite phase had reacted with HF, leaving only corundum. In the inner part of the brick, both mullite and corundum crystals still existed. Refractory selection guidelines are suggested. [source] Effect of Silicate-Substitution on Attachment and Early Development of Human Osteoblast-Like Cells Seeded on Microporous Hydroxyapatite Discs,ADVANCED ENGINEERING MATERIALS, Issue 1-2 2010Katharina Guth Hydroxyapatite (HA) is a well-established graft material used in bone repair. Silicon-substituted hydroxyapatite (SA; 0.8,wt% Si) has shown greater bone ingrowth and bone coverage than phase pure HA. To assess the effect of microporosity on sensitivity of cell attachment to surface physiochemistry, microporous SA and HA discs, and control Thermanox (TMX) discs were incubated with osteoblast-like cells (5,×,104 HOS-TE85 cells) under differing tissue culture conditions. To investigate early cellular attachment, organization, and differentiation, cells were also stained for integrin,,5,1, actin, and runt-related transcription factor (RUNX-2), respectively, after incubation on HA, SA, and TMX discs for 3 days. No significant differences emerged between HA, SA, and TMX discs in mean numbers of cells attached in serum free medium (SFM) over 90,min incubation. In contrast, significantly more cells were attached to SA than HA after 180,min incubation in complete medium (C-MEM) containing fetal calf serum (p,<,0.05). Cell attachment to SA and HA discs pre-conditioned in SFM supplemented with fibronectin (FN) was lower than discs pre-conditioned in C-MEM, suggesting sensitivity of an active FN conformation to the presence of co-adsorbates. Confocal microscopy demonstrated significantly more co-localization of integrin ,5,1 and actin on SA than HA. Translocalization of RUNX-2 to the nucleus was stronger in cells incubated on SA. Microporosity did not diminish the effect of surface physiochemistry on cell adhesion, and enhanced cell attachment for SA appears to be mediated by differences in the quality of adsorbed protein rather than via direct effects of substrate chemistry. [source] Mechanisms and modes for ignition of low-voltage, PVC-insulated electrotechnical productsFIRE AND MATERIALS, Issue 2 2006Vytenis BabrauskasArticle first published online: 1 AUG 200 Abstract PVC is the most common insulation material used for wiring in low-voltage (LV) service. ,Low-voltage', in the context of this paper, is taken to be 120,240 VAC. The electrotechnical products considered include insulated wires, cables and cords, and also appurtenant termination devices, e.g. male plugs or female taps. Well-known factors leading to the ignition of PVC-insulated wiring and related products include: (a) manufacturing defects; (b) grossly excessive current; (c) over-insulation, sometimes augmented by overcurrent; (d) localized heating due to strand breakage; (e) localized heating due to mechanical strand severing by staples or nails; and (f) localized heating due to failed terminations. Other failure modes are known but have received only limited study. These include (i) excessive force and creep; (ii) chemical interaction effects; and (iii) breakdown under voltage surge conditions. Additional research is needed in these areas. The proximate cause of ignition involved with many of the above mechanisms is arc tracking (arcing across a carbonized path). In turn, it is shown that PVC is especially susceptible to becoming charred, it requiring only approximately 160°C for the material to become semiconducting during short-term exposure (around 10 h), while longer-term exposure (around 1 month) may cause failures at temperatures as low as 110°C. Some limited data exist which suggest that standard UL and IEC temperature classifications are unduly optimistic, as applied to PVC. Fire can originate if wiring or equipment cannot withstand a powerline surge. Mains-connected electrical appliances need to be designed to resist 6000 V surge voltages, even though this is not mandated in most of the current UL and IEC standards. Data are presented showing that the IEC 60112 wet-tracking test gives especially misleading results for PVC and should be improved or abrogated. Copyright © 2005 John Wiley & Sons, Ltd. [source] Sodium Borohydride Hydrolysis as Hydrogen Generator: Issues, State of the Art and Applicability Upstream from a Fuel CellFUEL CELLS, Issue 3 2010U. B. Demirci Abstract Today there is a consensus regarding the potential of NaBH4 as a good candidate for hydrogen storage and release via hydrolysis reaction, especially for mobile, portable and niche applications. However as gone through in the present paper two main issues, which are the most investigated throughout the open literature, still avoid NaBH4 to be competitive. The first one is water handling. The second one is the catalytic material used to accelerate the hydrolysis reaction. Both issues are objects of great attentions as it can be noticed throughout the open literature. This review presents and discusses the various strategies which were considered until now by many studies to manage water and to improve catalysts performances (reactivity and durability). Published studies show real improvements and much more efforts might lead to significant overhangs. Nevertheless, the results show that we are still far from envisaging short-term commercialisation. [source] A Multiscale Description of the Electronic Transport within the Hierarchical Architecture of a Composite Electrode for Lithium BatteriesADVANCED FUNCTIONAL MATERIALS, Issue 17 2009Jean-Claude Badot Abstract The broadband dielectric spectroscopy technique is applied, for the first time, to a composite material used as an electrode for lithium battery. The electrical properties (permittivity and conductivity) are measured from low (a few Hz) to microwave (a few GHz) frequencies. The results demonstrate that the broadband dielectric spectroscopy technique is very sensitive to the different scales of the electrode architecture involved in electronic transport, from interatomic distances to macroscopic sizes, as well as to the morphology at these scales, coarse or fine distribution of the constituents. This work opens up new prospects for a more fundamental understanding and more rational optimization of the electronic transport in composite electrodes for lithium batteries and other electrochemical energy storage technologies (including other batteries, supercapacitors, low- and medium-temperature fuel cells), electrochemical sensors and conductor,insulator composite materials. [source] Analysis of adobe wall composition at the Chaves-Hummingbird Site, New Mexico, by diffuse reflectance spectrophotometryGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 8 2007William Balsam This article investigates adobe wall construction materials utilized by prehistoric inhabitants of Chaves-Hummingbird Pueblo, an ancestral Pueblo village located ,20 miles west of Albuquerque, New Mexico. The walls were constructed with native clay-rich soils some time between approximately 1275,1450 A.D. Samples were analyzed with a diffuse reflectance spectrophotometer from the near ultraviolet (NUV) through the visible (VIS) and into the near infrared (NIR) region of the electromagnetic spectrum. Cluster analysis of samples from 275 adobe walls and 36 soil locations surrounding the pueblo room blocks indicates four clusters. Comparison of typical samples from the four clusters indicates that they are very similar and are distinguished by minor variations in the three primary spectrally determined components, Na-Ca montmorillonite, bentonite, and goethite. In general, clusters correspond with room construction episodes that are discernible through patterns of wall bonding and abutment recorded during the archaeological investigation of the site. This suggests that during different phases of construction the source of the wall adobe changed. Many of the soil samples are included in wall clusters and therefore reveal a potential source of material used for adobe, adjacent soils. However, not all the soil surrounding the pueblo grouped with wall clusters indicating a preference for certain soil types and that some soils were probably unsuitable for making adobe. Therefore, diversity in spectrally identified construction materials provides insights into source locations and possible construction preferences of the site inhabitants. © 2007 Wiley Periodicals, Inc. [source] Monte Carlo Study of Quantitative Electron Probe Microanalysis of Monazite with a Coating Film: Comparison of 25 nm Carbon and 10 nm Gold at E0= 15 and 25 keVGEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 2 2007Takenori Kato simulation par la méthode de Monte Carlo; microanalyse par sonde électronique (EPMA); analyse quantitative; film de revêtement; monazite Carbon (25,30 nm in thickness) is the most common coating material used in the electron probe microanalysis (EPMA) of geological samples. A gold coating is also used in special cases to reduce the surface damage by electron bombardment. Monte Carlo simulations have been performed for monazite with a 25 nm carbon and a 10 nm gold coating to understand the effect of a coating film in quantitative EPMA at E0= 15 keV and 25 keV. Simulations showed that carbon-coated monazite gave the same depth distribution of the generated X-rays in the monazite as uncoated monazite, whilst gold-coated monazite gave a distorted depth distribution. A 10 nm gold coating was 1.06 (15 keV) and 1.05 (25 keV) times higher in k -ratio between monazite and pure thorium than a 25 nm carbon coating at an X-ray take-off angle of 40 degrees. Thus, a 10 nm gold coating is a possible factor contributing to inaccuracy in quantitative EPMA of monazite, while a 25 nm carbon coating does not have a significant effect. Le carbone, avec des épaisseurs de 25 à 30 nm, est le matériel de dépôt le plus fréquemment utilisé en microanalyse par sonde électronique (EPMA) d'échantillons géologiques. Un dépôt d'or est aussi utilisé dans des cas spécifiques, pour réduire les dommages causés à la surface par le bombardement d'électrons. Des simulations par la méthode de Monte Carlo ont été effectuées pour une monazite recouverte d'une couche de carbone de 25 nm et d'une couche d'or de 10 nm, dans le but de comprendre l'effet du dépôt dans les mesures quantitatives à l'EPMA, à E0= 15 keV et 25 keV. Les simulations ont montré que la monazite recouverte de carbone avait la même distribution en profondeur de rayons X générés qu'une monazite non recouverte, tandis que la monazite recouverte d'or avait une distribution en profondeur déformée. Le dépôt de 10 nm d'or avait un k -ratio qui était 1.06 (pour 15 keV) et 1.05 (pour 25 keV) fois plus important pour la monazite et du thorium pur que le dépôt de 25 nm de carbone dans le cas d'un angle de sortie des rayons X de 40 degrés. En conséquence un dépôt d'or de 10 nm est un facteur possible d'inexactitude lors de mesures quantitatives de monazites par EPMA, alors qu'un dépôt de carbone de 25 nm n'a pas d'effet significatif sur la mesure. [source] Nature, production and regulation in eighteenth-century Britain and France: the case of the leather industry*HISTORICAL RESEARCH, Issue 211 2008Giorgio Riello Leather was, in the pre-industrial economy, a scarce material used in the production of a wide range of goods. The supply of leather was influenced by the national cattle asset and its slaughtering rate. The difficulty in increasing leather production to meet the demands of a ,consumer revolution' was the subject of theoretical debates and practical intervention. The state controlled and organized the leather market through fiscal and commercial policies. This article offers a comparative analysis of the French and the British leather markets in the eighteenth century. In France, the state assumed an organizational function in the creation of a national leather market. In Britain, by contrast, the state simply regulated an existing market. These different political interventions influenced the dynamics of development of leather production and the leather trades in the two countries. While France suffered from an endemic absence of leather, Britain was able to satisfy its increasing demand efficiently. [source] A finite volume,multigrid method for flow simulation on stratified porous media on curvilinear co-ordinate systemsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 4 2001Pablo Calvo Abstract This paper presents a numerical study of infiltration processes on stratified porous media. The study is carried out to examine the performance of a finite volume method on problems with discontinuous solutions due to the transmission conditions in the interfaces. To discretize the problem, a curvilinear co-ordinate system is used. This permits matching the interface with the boundary of the control volumes that interchange fluxes between layers. The use of the multigrid algorithm for the resulting systems of equations allows problems involving a large number of nodes with low computational cost to be solved. Finally, some numerical experiments, which show the capillary barrier behaviour depending on the material used for the different layers and the geometric design of the interface, are presented. Copyright © 2001 John Wiley & Sons, Ltd. [source] Performance assessment under field conditions of a rapid immunological test for transgenic soybeansINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 4 2001John Fagan Summary Current market conditions and food regulations make it necessary for international and domestic participants in the agrifood industry to structure supply chains that control the content of genetically modified (GM) material in their products. Tests to detect and/or quantify GM components represent an important tool in maintaining such supply systems. This study assesses the field performance of kits that employ lateral flow immuno-technology to detect soybeans GM to be resistant to the herbicide glyphosate. Operators at 23 grain-handling facilities were paid to conduct analyses on a series of blinded samples containing defined proportions of conventional and transgenic soybeans. The observed rate of false positives was 6.7% in an experiment in which the highest level of GM material was 1% and 22.3% in a second experiment in which the highest level of GM material was 10%. This difference may be attributed to increased risk of cross-contamination with the higher level of transgenic material used in the second study. Samples containing 0.01% GM material were reported as genetically modified 6.70% of the time, while samples containing 0.1, 0.5 and 1% GM material were classified as genetically modified 29.5, 67.7 and 68.2% of the time, respectively. Thus, the frequencies of false negatives were 93.3, 70.5, 33.3 and 31.8% for samples containing 0.01, 0.1, 0.5 and 1.0% GM material. Samples containing 10% GM material were correctly reported as genetically modified in all cases. These results lead to the conclusion that the kit under study is useful in screening for lots of soybeans that contain high levels of GM material, but that, as a field tool, it is not effective in monitoring for GM material at the level of 1.0% or lower. Statistical and immunochemical analyses were carried out in order to assess the relative contributions of various factors to the error observed in these studies. These analyses indicated that limitations in operator performance, not defects in test kit materials, were the primary contributors, while sample size may play a secondary role. As both operator performance and sample size are independent of the specific characteristics of the test kit used in this study, it appears justifiable to generalize conclusions obtained here to other similar test systems. [source] Visualization study and analysis on preform growth in polyethylene terephthalate stretch blow moldingJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007Han-Xiong Huang Abstract In stretch blow molding (SBM) process, the preform growth during the stretching and blowing is critical to the thickness distribution and properties of the final bottle. Whereas the thickness distribution is one of the most important criteria in the production of bottles. So this work focused on the polyethylene terephthalate (PET) preform growth using a transparent mold, through which the instantaneous images of the preform in the stretching and blowing stage were captured. By changing the delay time of the preblow, the three preform growth types, referred to as dolphin, sandpile, and two-bubble, were observed. The longitudinal and hoop stresses acting on the preform segment during the stretching and blowing were analyzed. Two parameters, on which the longitudinal and hoop stresses depend, respectively, were defined. Then combining the geometry and sizes of the preform, the stresses and temperature distribution on it, and the stress,strain curves of the PET material used, the cause for different preform growth types was systematically analyzed. On the basis of preform growth types, the thickness distributions of the bottles obtained under different delay times of the preblow were explained. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 564,573, 2007 [source] Band-related leg injuries in an Australian passerine and their possible causesJOURNAL OF FIELD ORNITHOLOGY, Issue 2 2006Kate Splittgerber ABSTRACT We examined the extent and causes of band-related leg injuries in an Australian passerine, the Bell Miner (Manorina melanophrys). Eight percent of banded birds exhibited leg injuries, and most were birds with two plastic color bands on a tarsus. Leg injuries typically followed the accumulation of shed tarsal scales under the color bands. Color bands used on Bell Miners were tighter on the tarsus than the metal band and also tighter than the color bands used on Superb Fairy-wrens (Malurus cyaneus), a commonly banded species with no reported leg injuries. The tendency for scales to accumulate under two plastic color bands appeared to be influenced by the diameter of a band relative to the size of a bird's tarsus (with looser bands less likely to cause accumulation) and the material used to make the band (with smoother surfaces less likely to cause accumulation). Celluloid color bands had rougher internal surfaces than either Darvic or metal bands. In addition, both celluloid and Darvic color bands generated static electricity capable of attracting tarsal scales. Scales that accumulated under bands provided an environment where potentially harmful fungi became established, potentially contributing to the severity of leg injuries. Our results suggest that, when selecting an appropriate band size for a bird, the diameter of the tarsus at its midpoint should occupy only between 60% and 65% of the internal diameter of the band and, when possible, a single, bicolored, anodized aluminum alloy band should be used instead of multiple plastic color bands. SINOPSIS Examinamos la causa y la extensión de lesiones en las patas causadas por anillas en Manorina melanophrys, en Australia. Un 8% de las aves mostraron lesiones en las patas, la mayoría aves con dos anillas plásticas. Las lesiones causaron la acumulación de escamas tarsales mudadas, bajo la anilla. Se encontraron que las anillas plásticas ejercían mas presión o estaban más ajustadas que las anillas de metal y que estaban más apretadas que en Malurus cyaneus, una especie comúnmente anillada y en donde no encontramos lesiones. La tendencia de acumulación de escamas bajo las dos anillas plásticas, parece ser influenciada por el diámetro de la anilla, con respecto al grosor del tarso del ave y del material con que estuvo echo la anilla. Encontramos que las anillas de celuloide tienen una superficie interna más áspera que las anillas de metal. Además, ambos tipos de anillas, generan estática capaz de atraer las escama de la pata. Las partículas de escama que se acumulan bajo una anilla proveen de una buena base para que se crezcan hongos, que contribuyen a la gravedad de la lesión en la pata. Sugerimos que se deben seleccionar anillas apropiadas en tamaño en donde el diámetro del tarso en la parte media de la pata, ocupe entre el 60,65% del diámetro interno de la anilla. También, que cuando sea posible, se utilice una sola anilla de metal pintada con dos colores, en vez de dos anillas plásticas. [source] DIRECT PLATING: A METHOD FOR DETECTING FUNGAL CONTAMINATION IN PAPERBOARD CARTONSJOURNAL OF FOOD SAFETY, Issue 3 2001JAN A. NARCISO ABSTRACT Contamination of refrigerated juice products in gable-top cartons can occur by filamentous fungi that are present in the paperboard. A method was developed to assay the mycoflora of paperboard carton material used in beverage packaging. This method involved direct plating on an agar surface of 1 cm2 carton pieces rather than disintegration of carton material in a blender prior to plating. When compared to the standard disintegration method traditionally used for monitoring contamination of paperboard, the new method is less cumbersome, more efficient, and reduces opportunities for contamination. The number of colonies produced by the direct plating method was greater than or equal to the modified standard disintegration method. Direct plating also resulted in a larger number of different genera isolated. [source] Stability of Lactobacillus reuteri in Different Types of MicrocapsulesJOURNAL OF FOOD SCIENCE, Issue 1 2006Parthiban Muthukumarasamy ABSTRACT: This study was designed to find the most suitable method and wall material for microencapsulation of the probiotic bacterium Lactobacillus reuteri to maintain cell viability during gastric challenge. Five L. reuteri strains were individually encapsulated using alginate, alginate plus starch, K-carrageenan with locust bean gum, or xanthan with gellan by extrusion or phase separation (emulsion). The morphology of the microcapsules was studied using phase contrast and cryo-scanning electron microscopy (cryo-SEM). The resistance of these microcapsules and the viability of contained L. reuteri to simulated gastric juice were studied. The shape and size of the microcapsules produced varied with the preparation method and type of wall material. Extruded microcapsules were larger and more uniformly shaped. Survival of microencapsulated L. reuteri was significantly better than that of planktonic cells and varied with the strain, method of microencapsulation, and wall material used. In general, microencapsulation using alginate and alginate with starch by both extrusion and phase separation were found to provide bacteria significantly greater protection (P < 0.05) against simulated gastric juice. [source] Mechanics of column beds: I. Acquisition of the relevant parametersAICHE JOURNAL, Issue 3 2003Bee Gaik Yew The efficiency of chromatographic columns is adversely affected by large-scale radial variations of the packing density or void ratio of the material used to prepare the bed. This heterogeneity is due to wall friction effects that take place during the preparation of the column and to seepage effects operating during the packing process and the subsequent operation of the column. The dependence of the bed's void fraction on the stress applied during its consolidation was determined, as well as its permeability at various stages of the consolidation process and the coefficient of friction between typical packing materials and the stainless steel wall of chromatographic columns. These results are required to develop and use numerical models of the volumetric response to axial compression of the bed and models of the coupled mechanical-seepage rheology of particulate materials. [source] Mechanics of column beds: II.AICHE JOURNAL, Issue 3 2003Modeling of coupled stress-strain-flow behavior The rheological behavior of a bed of packing material during its consolidation was investigated using an elastic-plastic model, the Frictional Material Model. This model takes into account the behavior of the packing material under compression stress, its consolidation, its internal friction, its friction against the column wall, and the dependence of the bed's permeability on the local void fraction. The complexity of the problem arises from the nonlinear behavior of the relationships between the critical parameters controlling the column bed behavior and the external stresses applied to this bed. Solutions of the model were calculated for combinations of axial compression and seepage stresses, the latter corresponding to the flow of the mobile-phase stream under typical conditions used in HPLC. The results demonstrate the importance of the internal angle of friction of the packing material used on the degree of radial and axial heterogeneity of the beds of chromatographic columns packed with this material. [source] Potential sources of background contaminants in solid phase extraction and microextractionJOURNAL OF SEPARATION SCIENCE, JSS, Issue 7 2007Robert Stiles Abstract A study to identify the sources of background contamination from SPE, using a C-18 sorbent, and solid-phase microextraction (SPME), using a 70 ,m carbowax/divinylbenzene (CW/DVB) fiber, was carried out. To determine the source of contamination, each material used in the procedure was isolated and examined for their contribution. The solid-phase column components examined were: sorbent material and frits, column housings and each solvent used to elute analytes off the column. The components examined in the SPME procedure were: SPME fiber, SPME vials, water (HPLC grade), and salt (sodium chloride) used to increase the ionic strength. The majority of the background contaminants from SPE were found to be from the SPE sorbent material and frits. The class of contaminants extracted during a blank extraction were phthalates and other plasticizers used during the manufacturing process. All had blank levels corresponding to measured concentrations below 2 ng/mL, except for undecane, which had a concentration of 5.4 ng/mL. The most prevalent contaminants in the SPME blank procedure are 1,9-nonanediol, a mixture of phthalates and highly bis- substituted phenols. All the concentrations were below 2 ng/mL, with the exception of bis (2-ethylhexyl) phthalate, which had concentrations ranging from 5 to 20 ng/mL. [source] Ni,YSZ Solid Oxide Fuel Cell Anode Behavior Upon Redox Cycling Based on Electrical CharacterizationJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2007Trine Klemensø Nickel (Ni),yttria-stabilized zirconia (YSZ) cermets are a prevalent material used for solid oxide fuel cells. The cermet degrades upon redox cycling. The degradation is related to microstructural changes, but knowledge of the mechanisms has been limited. Direct current conductivity measurements were performed on cermets and cermets where the Ni component was removed. Measurements were carried out before, during, and after redox cycling the cermet. The cermet conductivity degraded over time due to sintering of the nickel phase. Following oxidizing events, the conductivity of the cermets improved, whereas the conductivity of the YSZ phase decreased. An improved model of the redox degradation mechanism was established based on the measurements. [source] Crack Healing Behavior of Silicon Carbide CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2000Jan Korou This study focuses on the crack healing behavior of three kinds of commercial SiC ceramics. Specimens with and without cracks were subjected to thermal treatment at different temperatures, and their strengths were measured by a three-point bending test in accordance with JIS standards. The tests were performed in air at both room temperature and elevated temperatures between 600° and 1500°C. The healed specimens showed a complete recovery of strength at room temperature for the investigated crack sizes of 2c, 100 ,m and 2c, 200 ,m, and their strength increased in accordance with the healing temperature. The behavior of the healed specimens at elevated temperatures was influenced by the material used and the test temperature. Generally, the strength decreased at a high temperature, but the degree of strength reduction was determined by the kind of ceramic. The most important difference between the healed and smooth specimens was exhibited in material A. It was observed that at 1400°C, the bending strength of the healed specimens made from this ceramic was about 37% of the value for specimens in an as-received state. Static fatigue tests were also performed for ceramic B at 900° and 1000°C. The experiment demonstrated that the static fatigue limit of a healed specimen is about 75% of the monotonic bending strength at the same temperature. [source] Metallic dental materials in patient's oral cavity acting as electrodes of electrochemical cellsMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 7 2004W. Opydo Abstract The work was aimed at studying of standard potentials of commonly used metallic dental materials and determining of the effect of saliva conductivity and reaction on value of the potentials. The following materials have been examined: gold alloy (a material used for crowns and bridgeworks), chromium-cobalt alloy (for frameworks in removable partial dentures), and silver amalgams (used for fillings) manufactured by three different companies. Taking into account that mucosa makes one of the electrodes existing in oral cavity the rest potentials of mucosa have been in vivo measured in several patients. Their values, converted with respect to NHE, oscillated within the range from + 0.31 V to + 0.47 V. Among metallic dental materials examined in the experiment maximal standard potential was found for the gold alloy, further materials having lower potentials, in decreasing order, were chromium-cobalt alloy, and the amalgams Amalcap Plus, ANA 2000 and Septalloy. Significant differences between standard potentials of examined materials and mucosa indicate spontaneous formation of galvanic cells of electromotive force reaching even about 0.6 V. [source] Hollow core photonic band gap fiber for THz applicationsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2009Luca Vincetti Abstract In this article, a hollow core photonic band gap fiber is numerically investigated to obtain low-loss waveguiding in the terahertz region (0.1,10 THz) of the electromagnetic spectrum. Waveguide design in this spectral region is an arduous challenge due to the high-conductivity losses of metals and high-absorption of the dielectrics. Numerical results show the possibility to reach propagation loss two decades lower than the bulk absorption losses of the material used to fabricate the fiber, and low dispersion over a wide range of wavelength. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1711,1714, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24407 [source] | ||||||||||||||||||||||||||||