Model for Analysis of Short Columns of Concrete Confined by Fiber-Reinforced Polymer

This paper presents a numerical model for evaluating the behavior of axially loaded rectangular and cylindrical short columns of concrete confined by fiber-reinforced polymer (FRP) composites. The proposed formulation considers, for unconfined and confined compressed concrete, a uniaxial constitutive relation that utilizes the area strain as a parameter of measure of the material secant axial stiffness. For unconfined concrete, the model adopts an explicit relationship between axial strain and lateral strain, while for confined concrete, an implicit relation is considered. For this last case, the model employs a simple iterative-incremental approach that describes the entire stress-strain response of the columns. The behavior of the FRP is considered linear elastic until the rupture. To validate the model, a number of columns were analyzed and the numerical results were compared with experimental values published by other authors. This comparison between experimental and numerical results indicates that the model provides satisfactory predictions of the stress-strain response of the columns.     

Carbon dioxide of Pu`u`O`o volcanic plume at Kilauea retrieved by AVIRIS hyperspectral data

A remote sensing approach permits for the first time the derivation of a map of the carbon dioxide concentration in a volcanic plume. The airborne imaging remote sensing overcomes the typical difficulties associated with the ground measurements and permits rapid and large views of the volcanic processes together with the measurements of volatile components exolving from craters. Hyperspectral images in the infrared range (1900-2100 nm), where carbon dioxide absorption lines are present, have been used. These images were acquired during an airborne campaign by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) over the Pu`u` O`o Vent situated at the Kilauea East Rift zone, Hawaii. Using a radiative transfer model to simulate the measured up-welling spectral radiance and by applying the newly developed mapping technique, the carbon dioxide concentration map of the Pu`u` O`o Vent plume were obtained. The carbon dioxide integrated flux rate were calculated and a mean value of 396 ± 138 t d^− 1 was obtained. This result is in agreement, within the measurements errors, with those of the ground measurements taken during the airborne campaign.     

Topographic normalization for improving vegetation classification in a mountainous watershed in Northern Thailand

Land cover classifications are adversely affected by shading or topographic effects in mountainous areas in that the spectral properties of an entity in the shade appear to be different from those of the same entity in a sunlit area. Topographic effects can make it especially difficult to distinguish different successional stages of vegetation. The current work uses a simplified topographic normalization method to reduce the topographic effect and to improve land cover classification in a mountainous watershed in northern Thailand. Data used in the study were two Landsat 7 Enhanced Thematic Mapper Plus (ETM+) images acquired on 5 March 2000 and 7 February 2002, a digital elevation model, and Global Positioning Systems (GPS) ground truth data collected in July 2002 consisting of geographic location (latitude/longitude), feature information and ground reference photographs. A supervised land cover classification was conducted on original and normalized images. In general, the classification accuracy of the different successional stages of vegetation was improved in the normalized images.     

Recovery of methane from anaerobic process effluent using poly-di-methyl-siloxane membrane contactors

This paper demonstrates the potential for recovering dissolved methane from low temperature anaerobic processes treating domestic wastewater. In the absence of methane recovery, ca. 45% of the produced methane is released as a fugitive emission which results in a net carbon footprint of -0.47 kg CO(2e) m(-3). A poly-di-methyl-siloxane (PDMS) membrane contactor was applied to support sweep gas desorption of dissolved methane using nitrogen. The dense membrane structure controlled gaseous mass transfer thus recovery was maximised at low liquid velocities. At the lowest liquid velocity, V(L), of 0.0025 m s(-1), 72% of the dissolved methane was recovered. A vacuum was also trialled as an alternative to sweep-gas operation. At vacuum pressures below 30 mbar, reasonable methane recovery was observed at an intermediate V(L) of 0.0056 m s(-1). Results from this study demonstrate that dissolved methane recovery could increase net electrical production from low temperature anaerobic processes by ca. +0.043 kWh(e) m(-3) and reduce the net carbon footprint to +0.01 kg CO(2e) m(-3). However, further experimental work to optimise the gas-side hydrodynamics is required as well as validation of the long-term impacts of biofouling on process performance.     

Evaluation of epoxy resin sealer after three root canal filling techniques by confocal laser scanning microscopy

The aim of this study was to evaluate the penetration of endodontic sealer into the dentin tubules, the integrity of the sealer layer perimeter, and the sealer area at the apical third after different filling techniques by confocal laser scanning microscopy (CLSM). Forty‐five mandibular premolars were mechanically prepared with ProTaper files, until F5 file. Thereafter, they were filled with an epoxy‐resin sealer (AH Plus) mixed with Rhodamine B dye (0.1% proportion) and allocated in three groups: Group 1, single master cone; Group 2, cold lateral compaction; and Group 3, Thermafil. For confocal laser scanning microscopy analysis, the specimens were transversely sectioned at 4 mm from the apex. The images at ×10 and ×40 were analyzed by Imagetool 3.0 software. Significant differences were not found among the three experimental groups according the dentin‐impregnate area by the sealer (P = 0.68) and between the sealer and root canal perimeter (P = 0.18). However, root canal filling techniques were significantly different when apical sealer areas were compared (P = 0.001). Thermafil group showed smaller sealer areas (8.09%) while cold lateral compaction and gutta‐percha master cone showed similar areas (17.37 and 21.18%, respectively). The dentin‐impregnated area was not dependent on the root canal filling technique. Single master cone, cold lateral condensation and Thermafil techniques presented integrity of the sealer perimeter close to 100% and Thermafil resulted in a significantly thinner sealer layer. Microsc. Res. Tech. 75:1277–1280, 2012. © 2012 Wiley Periodicals, Inc.     

Investigation of capillary flow in discrete cracks in cementitious materials

A series of experimental studies are presented that simulate capillary flow of water in discrete cracks in cementitious materials. A number of amendments to existing capillary flow theory are adopted which take the form of correction parameters for stick–slip behaviour of the meniscus, frictional dissipation at the meniscus wall boundary and slip between the fluid and solid wall. A benchmark study to examine capillary flow in small diameter glass capillaries is reported and this provides data to validate the amended theoretical model. Predictions made using the amended model closely match the experimental results of capillary rise in discrete cracks in cementitious materials allowing the correction parameters for capillary flow in planar cracks to be determined. Finally, capillary rise in a discrete natural crack of known aperture is considered and a relationship is proposed which predicts the capillary rise response in a natural crack in terms of an equivalent planar crack.     

The scope for potential energy savings in the flocculation process

Water treatment plants traditionally use coagulation/flocculation process to remove organics and turbidity particles in drinking water. As a result of the chemical optimisation of the coagulation process having such a strong influence, it is believed that the current hydraulic conditions for flocculation cited under best practice could be out of date. A 450 Mld plant treating upland water was chemically optimised, and it was observed that the total mixing energy input could be reduced by 66% without any detrimental impact upon the clarified water being observed. Under the new mixing regime, energy costs could be reduced by £37 300 pa equating to approximately a 280 t reduction in CO ₂.     

Drying of plums (Prunus sp,c.v Gulfblaze) treated with KCl in the field and subjected to pulsed vacuum osmotic dehydration

The pulsed vacuum osmotic dehydration (PVOD) promotes more homogeneous concentration profiles in the product and quality improvement of several fruits. The objective of this work was to study the drying of plums submitted to treatments of plants manure with KCl and PVOD (5” c.a., 10 min). Experimental planning was done with the following independent variables: doses of KCl (400, 700 and 1000 g/plant), concentration of sucrose solution (40; 50 and 60 ºBrix) and drying temperature (50, 60 and 70C). The tested variables were: color, shrinkage, visual quality and rehydration. Temperature leads to a skin browning at fruit pulps and lower visual quality. The treatment with KCl leads to final products with lower moisture content. The higher the values of all the independent variables, the lower the shrinkage and the rehydration capacity. Plums submitted to convective drying with previous PVOD promote a new product with good visual quality and satisfactory shrinkage.     

Skeletal classification of maxillary and mandibular malpositions

Criteria used to establish ideal skeletal position of the maxilla and mandible relative to the cranial base is exacting. It must first enhance facial esthetics and facial profile. Secondly, it must improve TMJ health; and finally, it must improve physiologic harmony. Physiologic harmony include alleviation of many medical symptoms such as migraine headaches, neck-shoulder-back pain, myalgia, mouth breathing, otitis media, ringing in the ear, dizziness, vertigo, etc. The Skeletal Archial Analysis is a powerful diagnostic aid. Once the skeletal landmarks are learned, it takes clinicians less than 5 minutes to trace and diagnose. This is because it uses visual references rather than columns of angles and linear measurements. How powerful and accurate is this analysis? If done correctly, patients treated to their anterior arc and correct vertical arc will often times achieve significant facial esthetics, TMJ health, and physiologic harmony. Both the Skeletal Archial Analysis and the Skeletal Classification System indicate whether the disharmony is in the maxilla, mandible, or both. They clearly show in which direction these skeletal structures must be moved to enhance facial appearance and health. In all cases, the direction is to move these structures as close to skeletal Type I, Normal, as physiologically possible. Figure 8 shows a 21-year-old female individual with this skeletal classification. She has ideal maxillary and mandibular A-P position and ideal lower facial height. As can be seen, she has an attractive facial profile and she has no clinical symptoms of temporomandibular disorder or other medical problems. Conversely, patients with facial disharmony often seem to have various medical problems, including premenstrual syndrome and infertility. Once clinicians become adept at using the Skeletal Archial Analysis, they will begin to see many more types of facial disharmonies than previously thought. It then becomes a verbal challenge to accurately describe the multitude of different types of skeletal malpositions. In light of this, it is important that a universal Skeletal Classification System be established to promote better understanding in the diagnosis and treatment of facial-skeletal problems.     

Role of carbohydrate-mediated adherence in cytopathogenic mechanisms of Acanthamoeba

Acanthamoeba keratitis is a vision-threatening corneal infection. The mannose-binding protein of Acanthamoeba is thought to mediate adhesion of parasites to host cells. We characterized the amoeba lectin with respect to its carbohydrate binding properties and the role in amoeba-induced cytopathic effect (CPE). Sugar inhibition assays revealed that the amoeba lectin has the highest affinity for alpha-Man and Man(alpha1-3)Man units. In vitro cytopathic assays indicated that mannose-based saccharides which inhibit amoeba adhesion to corneal epithelial cells were also potent inhibitors of amoeba-induced CPE. Another major finding was that N-acetyl-D-glucosamine (GlcNAc) which does not inhibit adhesion of amoeba to host cells is also an inhibitor of amoeba-induced CPE. The Acanthamoebae are thought to produce CPE by secreting cytotoxic proteinases. By zymography, one metalloproteinase and three serine proteinases were detected in the conditioned media obtained after incubating amoebae with the host cells. The addition of free alpha-Man and GlcNAc to the co-culture media inhibited the secretion of the metalloproteinase and serine proteinases, respectively. In summary, we have shown that the lectin-mediated adhesion of the Acanthamoeba to host cells is a prerequisite for the amoeba-induced cytolysis of target cells and have implicated a contact-dependent metalloproteinase in the cytopathogenic mechanisms of Acanthamoeba.