Turning Point zapper test of moment by moment voting

This short 3 min video shows how Camtasia Studio can be used to record the audio of a lecture alongside the moment-by-moment votes recorded using Turning Point.

EVALUATION OF INTELLIGENT COMPACTION CONTROL IN THE M-189 RECONSTRUCTION PROJECT AT IRON RIVER, MICHIGAN

This research evaluated an Intelligent Compaction (IC) unit on the M-189 highway reconstruction project at Iron River, Michigan. The results from the IC unit were compared to several traditional compaction measurement devices including Nuclear Density Gauge (NDG), Geogauge, Light Weight Deflectometer (LWD), Dynamic Cone Penetrometer (DCP), and Modified Clegg Hammer (MCH). The research collected point measurements data on a test section in which 30 test locations on the final Class II sand base layer and the 22A gravel layer. These point measurements were compared with the IC measurements (ICMVs) on a point-to-point basis through a linear regression analysis. Poor correlations were obtained among different measurements points using simple regression analysis. When comparing the ICMV to the compaction measurements points. Factors attributing to the weak correlation include soil heterogeneity, variation in IC roller operation parameters, in-place moisture content, the narrow range of the compaction devices measurement ranges and support conditions of the support layers. After incorporating some of the affecting factors into a multiple regression analysis, the strength of correlation significantly improved, especially on the stiffer gravel layer. Measurements were also studied from an overall distribution perspective in terms of average, measurement range, standard deviation, and coefficient of variance. Based on data analysis, on-site project observation and literature review, conclusions were made on how IC performed in regards to compaction control on the M-189 reconstruction project.

Investigation of the fracture mode for hard and soft wheat endosperm using the loading-unloading bending test

Investigation of the fracture mode for hard and soft wheat endosperm was aimed at gaining a better understanding of the fragmentation process. Fracture mechanical characterization was based on the three-point bending test which enables stable crack propagation to take place in small rectangular pieces of wheat endosperm. The crack length can be measured in situ by using an optical microscope with light illumination from the side of the specimen or from the back of the specimen. Two new techniques were developed and used to estimate the fracture toughness of wheat endosperm, a geometric approach and a compliance method. The geometric approach gave average fracture toughness values of 53.10 and 27.0 J m(-2) for hard and soft endosperm, respectively. Fracture toughness estimated using the compliance method gave values of 49.9 and 29.7 J m(-2) for hard and soft endosperm, respectively. Compressive properties of the endosperm in three mutually perpendicular axes revealed that the hard and soft endosperms are isotropic composites. Scanning electron microscopy (SEM) observation of the fracture surfaces and the energy-time curves of loading-unloading cycles revealed that there was a plastic flow during crack propagation for both the hard and soft endosperms, and confirmed that the fracture mode is significantly related to the adhesion level between starch granules and the protein matrix.

Stress tests of ODP Site 131-808 sediments

Sediments undergoing accretion in trench-forearc systems are subjected to conditions of large lateral thrusting. This stress regime controls the mechanism of faulting as well as the yield and strength properties of the sediment. Understanding them is therefore crucial for the construction of quantitative models of sediment dynamics in convergent margin settings. For this purpose triaxial and oedometer tests were performed on six whole-round core samples recovered from Site 808 from depths between 173 and 705 mbsf. Samples from five depth intervals were subjected to a triaxial test program that was primarily designed to define yield and strength behavior. Test specimens were cut parallel and normal to the core axis. Additional five oedometer tests with similarly prepared specimens were performed on samples from four depth intervals to evaluate the directional state and degree of sediment compaction. Test results show that the degree of sediment compaction is higher than expected from overburden. This overcompaction increases with depth. A well-developed mechanical anisotropy is evident in all samples tested, regardless of their depth and lithology. Values of yield limit, stiffness, and shear strength are up to 40% higher in the horizontal direction compared to the vertical direction. In addition the test data demonstrate that the axis of the volumetric yield loci have rotated into extensional stress field. This verifies that the mechanical state of sediment in the accretionary wedge is controlled by in-situ stress conditions of extensional nature. The coefficients of lateral stress inferred suggest that the extensional stress regime becomes increasingly effective with depth.

Evaluation of random plasma cortisol and the low dose corticotropin test as indicators of adrenal secretory capacity in critically ill patients: A prospective study

It is unclear whether a random plasma cortisol measurement and the corticotropin (ACTH) test adequately reflect glucocorticoid secretory capacity in critical illness. This study aimed to determine whether these tests provide information representative of the 24 hour period. Plasma cortisol was measured hourly for 24 hours in 21 critically ill septic patients followed by a corticotropin test with 1 μ g dose administered intravenously. Serum and urine were analysed for ACTH and free cortisol respectively. Marked hourly variability in plasma cortisol was evident (coefficient of variation 8-30%) with no demonstrable circadian rhythm. The individual mean plasma cortisol concentrations ranged from 286 59 nmol/l to 796 &PLUSMN; 83 nmol/l. The 24 hour mean plasma cortisol was strongly correlated with both random plasma cortisol (r(2) 0.9, P< 0.0001) and the cortisol response to corticotropin (r(2) 0.72, P< 0.001). Only nine percent of patients increased their plasma cortisol by 250 nmol/l after corticotropin (euadrenal response). However, 35% of non-responders had spontaneous hourly rises > 250 nmol/l thus highlighting the limitations of a single point corticotropin test. Urinary free cortisol was elevated (865&PLUSMN; 937 nmol) in both corticotropin responders and non-responders suggesting elevated plasma free cortisol. No significant relationship was demonstrable between plasma cortisol and ACTH. We conclude that although random cortisol measurements and the low dose corticotropin tests reliably reflect the 24 hour mean cortisol in critical illness, they do not take into account the pulsatile nature of cortisol secretion. Consequently, there is the potential for erroneous conclusions about adrenal function based on a single measurement. We suggest that caution be exercised when drawing conclusions on the adequacy of adrenal function based on a single random plasma cortisol or the corticotropin test.

Comportamento geotécnico de misturas de solo e resíduos de perfuração onshore

The drilling of wells for petroleum extraction generates rocks and soils fragments, among other residues. These fragments are denominated petroleum drilling gravel or simply petroleum drilling residue. On the sites of onshore exploration are formed big deposits of drilling gravel, an expensive final destination material. This work aims at evaluating the addition of drilling residue to a lateritic soil, as composite material, for construction of compacted fills for earth work projects. Soil and residue were evaluated by X-ray diffraction (XRD) and X-ray fluorescence (XRF) and by laboratory tests traditionally used in soil mechanics, as particle-size analysis of soils, determination of liquid and plasticity indexes and compaction test. After soil and residue characterization, soil-residue mixtures were studied, using dosages of 2,5%, 5%, 10%, and 15% of residue in relation to the dry soil mass. These mixtures were submitted to compaction test, CBR, direct shear test and consolidation test. The test results were compared to the current legislation of DNIT for compacted fill construction. The results showed that the mixtures presented the minimal necessary parameters, allowing, from the point of view of geotechnical analysis, the use of these mixtures for construction of compacted fills

Impact and fracture resistance of an experimental acrylic polymer with elastomer in different proportions

The purpose of this study was to evaluate the impact and fracture resistance of acrylic resins: a heat-polymerized resin, a high-impact resin and an experimental polymethyl methacrylate with elastomer in different proportions (10, 20, 40 and 60%). 120 specimens were fabricated and submitted to conventional heat-polymerization. For impact test, a Charpy-type impact tester was used. Fracture resistance was assessed with a 3-point bending test by using a mechanical testing machine. Ten specimens were used for each test. Fracture (MPa) and impact resistance values (J.m-1) were submitted to ANOVA - Bonferroni's test - 5% significance level. Materials with higher amount of elastomer had statistically significant differences regarding to impact resistance (p < 0.05). Fracture resistance was superior (p < 0.01) for high-resistance acrylic resin. The increase in elastomer concentration added to polymethyl methacrylate raised the impact resistance and decreased the fracture resistance. Processing the material by injection decreased its resistance to impact and fracture.

Comparison of physical and mechanical properties of microwave-polymerized acrylic resin after disinfection in sodium hypochlorite solutions

This study evaluated the color stability, surface roughness and flexural strength of a microwave-polymerized acrylic resin after immersion in sodium hypochlorite (NaOCl), simulating 20 min of disinfection daily during 180 days. Forty disk-shaped (15 x 4 mm) and 40 rectangular (65 x 10 x 3 mm) specimens were prepared with a microwave-polymerized acrylic resin (Onda-Cryl). Specimens were immersed in either 0.5% NaOCl, 1% NaOCl, Clorox/Calgon and distilled water (control). Color measurements were determined by a portable colorimeter. Three parallel lines, separated by 1.0 mm, were registered on each specimen before and after immersion procedures to analyze the surface roughness. The flexural strength was measured using a 3-point bending test in a universal testing machine with a 50 kgf load cell and a crosshead speed of 1 mm/min. Data were analyzed statistically by ANOVA and Tukey's test (?=0.05). There was no statistically significant differences (p>0.05) among the solutions for color, surface roughness and flexural strength. It may be concluded that immersion in NaOCl solutions simulating short-term daily use during 180 days did not influence the color stability, surface roughness and flexural strength of a microwave-polymerized acrylic resin.

Effect of repeated disinfections by microwave energy on the physical and mechanical properties of denture base acrylic resins

The present study evaluated the effect of repeated simulated microwave disinfection on physical and mechanical properties of Clássico, Onda-Cryl and QC-20 denture base acrylic resins. Aluminum patterns were included in metallic or plastic flasks with dental stone following the traditional packing method. The powder/liquid mixing ratio was established according to the manufacturer's instructions. After water-bath polymerization at 74ºC for 9 h, boiling water for 20 min or microwave energy at 900 W for 10 min, the specimens were deflasked after flask cooling and finished. Each specimen was immersed in 150 mL of distilled water and underwent 5 disinfection cycles in a microwave oven set at 650 W for 3 min. Non-disinfected and disinfected specimens were subjected to the following tets: Knoop hardness test was performed with 25 g load for 10 s, impact strength test was done using the Charpy system with 40 kpcm, and 3-point bending test (flexural strength) was performed at a crosshead speed of 0.5 mm/min until fracture. Data were analyzed statistically by ANOVA and Tukey's test (α= 0.05%). Repeated simulated microwave disinfections decreased the Knoop hardness of Clássico and Onda-Cryl resins and had no effect on the impact strength of QC-20. The flexural strength was similar for all tested resins.

Flexural and diametral tensile strength of composite resins

This study evaluated the flexural strength (sf) and the diametral tensile strength (st) of light-cured composite resins, testing the hypothesis that there is a positive relation between these properties. Twenty specimens were fabricated for each material (Filtek Z250- 3M-Espe; AM- Amelogen, Ultradent; VE- Vit-l-escence, Ultradent; EX- Esthet-X, Dentsply/Caulk), following ISO 4049 and ANSI/ADA 27 specifications and the manufacturers’ instructions. For the st test, cylindrical shaped (4 mm x 6 mm) specimens (n = 10) were placed with their long axes perpendicular to the applied compressive load at a crosshead speed of 1.0 mm/min. The sf was measured using the 3-point bending test, in which bar shaped specimens (n = 10) were tested at a crosshead speed of 0.5 mm/min. Both tests were performed in a universal testing machine (EMIC 2000) recording the fracture load (N). Strength values (MPa) were calculated and statistically analyzed by ANOVA and Tukey (a = 0.05). The mean and standard deviation values (MPa) were Z250-45.06 ± 5.7; AM-35.61 ± 5.4; VE-34.45 ± 7.8; and EX-42.87 ± 6.6 for st; and Z250-126.52 ± 3.3; AM-87.75 ± 3.8; VE-104.66 ± 4.4; and EX-119.48 ± 2.1 for sf. EX and Z250 showed higher st and sf values than the other materials evaluated (p < 0.05), which followed a decreasing trend of mean values. The results confirmed the study hypothesis, showing a positive relation between the material properties examined.

COMPARATIVE STUDY OF THE SENSITIVITY OF DIABETIC LOWER EXTREMITIES WITH AND WITHOUT ULCERS USING THE PSSD (TM)

Introduction To determine and compare thresholds of cutaneous sensitivity of lower extremities in diabetic patients with an ulcer on only one lower extremity Methods and Materials The study group included 20 patients with mean age of 61 6 and average time with diabetes of 12 4 years All patients were previously tested using Semmes-Weinstein monofilament 5 07 Sensitivity was evaluated using the two point discrimination test and the PSSD (TM) (Pressure-Specified Sensory Device) in order to assess touch thresholds in a quantitative manner, in g/mm(2) Three skin areas were tested hallux pulp, dorsum of foot and medial heel, including four tests 1 point static, 1 point moving, 2 points static and 2 points moving Results Mean 2 point discrimination distance in mm was higher in feet with ulcers, but the difference between extremities was only statistically significant for the hallux. With the PSSD (TM), all patients had higher pressure thresholds in feet with ulcers when compared with feet without ulcers, in all tests, with statistical significance Conclusion The PSSD (TM) was able to differentiate levels of sensation between extremities with and without ulcers in diabetic patients, with statistical significance

On the analysis of notched concrete beams: From measurement with digital image correlation to identification with boundary element method of a cohesive model

A way of coupling digital image correlation (to measure displacement fields) and boundary element method (to compute displacements and tractions along a crack surface) is presented herein. It allows for the identification of Young`s modulus and fracture parameters associated with a cohesive model. This procedure is illustrated to analyze the latter for an ordinary concrete in a three-point bend test on a notched beam. In view of measurement uncertainties, the results are deemed trustworthy thanks to the fact that numerous measurement points are accessible and used as entries to the identification procedure. (C) 2010 Elsevier Ltd. All rights reserved.

In vivo biological performance of a novel highly bioactive glass-ceramic (Biosilicate (R)): A biomechanical and histomorphometric study in rat tibial defects

This study aimed to investigate bone responses to a novel bioactive fully crystallized glass-ceramic of the quaternary system P(2)O(5)-Na(2)O-CaO-SiO(2) (Biosilicates (R)). Although a previous study demonstrated positive effects of Biosilicate (R) on in vitro bone-like matrix formation, its in vivo effect was not studied yet. Male Wistar rats (n = 40) with tibial defects were used. Four experimental groups were designed to compare this novel biomaterial with a gold standard bioactive material (Bioglass (R) 45S5), unfilled defects and intact controls. A three-point bending test was performed 20 days after the surgical procedure, as well as the histomorphometric analysis in two regions of interest: cortical bone and medullary canal where the particulate biomaterial was implanted. The biomechanical test revealed a significant increase in the maximum load at failure and stiffness in the Biosilicate group (R) (vs. control defects), whose values were similar to uninjured bones. There were no differences in the cortical bone parameters in groups with bone defects, but a great deal of woven bone was present surrounding Biosilicate (R) and Bioglass (R) 45S5 particulate. Although both bioactive materials supported significant higher bone formation; Biosilicate (R) was superior to Bioglass (R) 45S5 in some histomorphometric parameters (bone volume and number of osteoblasts). Regarding bone resorption, Biosilicate (R) group showed significant higher number of osteoclasts per unit of tissue area than defect and intact controls, despite of the non-significant difference in the osteoclastic surface as percentage of bone surface. This study reveals that the fully crystallized Biosilicate (R) has good bone-forming and bone-bonding properties. (C) 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 978: 139-147, 2011.

Composite pre-heating: Effects on marginal adaptation, degree of conversion and mechanical properties

Objectives. This study evaluated the effect of composite pre-polymerization temperature and energy density on the marginal adaptation (MA), degree of conversion (DC), flexural strength (FS), and polymer cross-linking (PCL) of a resin composite (Filtek Z350, 3M/ESPE). Methods. For MA, class V cavities (4mmx2mmx2mm) were prepared in 40 bovine incisors. The adhesive system Adper Single Bond 2 (3M/ESPE) was applied. Before being placed in the cavities, the resin composite was either kept at room-temperature (25 degrees C) or previously pre-heated to 68 degrees C in the Calset (TM) device (AdDent Inc., Danbury, CT, USA). The composite was then light polymerized for 20 or 40s at 600mW/cm(2) (12 or 24 J/cm(2), respectively). The percentage of gaps was analyzed by scanning electron microscopy, after sectioning the restorations and preparing epoxy resin replicas. DC (n = 3) was obtained by FT-Raman spectroscopy on irradiated and non-irradiated composite surfaces. FS (n = 10) was measured by the three-point-bending test. KHN (n = 6) was measured after 24h dry storage and again after immersion in 100% ethanol solution for 24 h, to calculate PCL density. Data were analyzed by appropriate statistical analyses. Results. The pre-heated composite showed better MA than the room-temperature groups. A higher number of gaps were observed in the room-temperature groups, irrespective of the energy density, mainly in the axial wall (p < 0.05). Composite pre-heating and energy density did not affect the DC, FS and PCL (p > 0.05). Significance. Pre-heating the composite prior to light polymerization similar in a clinical situation did not alter the mechanical properties and monomer conversion of the composite, but provided enhanced composite adaptation to cavity walls. (C) 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Contraction stress related to composite inorganic content

Objectives. The role of inorganic content on physical properties of resin composites is well known. However, its influence on polymerization stress development has not been established. The aim of this investigation was to evaluate the influence of inorganic fraction on polymerization stress and its determinants, namely, volumetric shrinkage, elastic modulus and degree of conversion. Methods. Eight experimental composites containing 1:1 BisGMA (bisphenylglycidyl dimethacrylate): TEGDMA (triethylene glycol dimethacrylate) (in mol) and barium glass at increasing concentrations from 25 to 60 vol.% (5% increments) were tested. Stress was determined in a universal test machine using acrylic as bonding substrate. Nominal polymerization stress was obtained diving the maximum load by the cross-surface area. Shrinkage was measured using a water picnometer. Elastic modulus was obtained by three-point flexural test. Degree of conversion was determined by FT-Raman spectroscopy. Results. Polymerization stress and shrinkage showed inverse relationships with filler content (R(2) = 0.965 and R(2) = 0.966, respectively). Elastic modulus presented a direct correlation with inorganic content (R(2) = 0.984). Degree of conversion did not vary significantly. Polymerization stress showed a strong direct correlation with shrinkage (R(2) = 0.982) and inverse with elastic modulus (R(2) = 0.966). Significance. High inorganic contents were associated with low polymerization stress values, which can be explained by the reduced volumetric shrinkage presented by heavily filled composites. (C) 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.