scholarly journals Effect of cotton padding on the setting properties of plaster slabs

2013 ◽  
Vol 95 (2) ◽  
pp. 107-109 ◽  
Author(s):  
D Barlow ◽  
R Bansal ◽  
T Barlow ◽  
SJ Rhee ◽  
JH Kuiper ◽  
...  
Keyword(s):  
Water Content ◽  
Water Immersion ◽  
Testing Machine ◽  
Materials Testing ◽  
Optimal Position ◽  
Three Point Bending ◽  
Before And After ◽  
Plastic Cylinder ◽  
Strength And Stiffness ◽  
American Society

Introduction Plaster of Paris (PoP) impregnated bandages have been used to maintain the position of bones and joints for over a century. Classically, wool dressing is applied to the limb before the PoP, which can then be moulded to the desired shape. A modification of this practice is to wrap the PoP bandages circumferentially in cotton before wetting and applying to the patient in an attempt to reduce inhalation of plaster dust and reduce mess. However, this may affect the water content of the cast and therefore also its setting properties and strength. This study compared the setting properties of PoP casts when used with and without cotton wrapping. Methods Sixty specimens, compliant with the American Society for Testing and Materials standards for three-point bending tests, were prepared, with thirty wrapped in cotton. All were weighed before and after water immersion, and wrapped around a plastic cylinder to mimic limb application. Bending stiffness and yield strength was measured on a servohydraulic materials testing machine at 2, 6, 12, 24, 48 and 72 hours. Results The water content of cotton-wrapped plaster was significantly higher (50%) than that of standard plaster. It had significantly lower strength up to 24 hours and significantly lower stiffness up to 72 hours. Conclusions The initial decrease in strength and stiffness of the cast wrapped in cotton may comprise the ability of the backslab to hold the joint or bone in an optimal position. Any modification of the standard plaster slab application technique should allow for the potential adverse effects on the plaster setting properties.

Failure of an Advanced Five Layers RT800 Composite

2015 ◽  
Vol 760 ◽  
pp. 299-304
Author(s):  
Vasile Gheorghe ◽  
Florin Teodorescu-Draghicescu ◽  
Dora Raluca Ionescu
Keyword(s):  
Mechanical Properties ◽  
Glass Fibers ◽  
Testing Machine ◽  
Experimental Tests ◽  
Specific Weight ◽  
Materials Testing ◽  
Bending Tests ◽  
Three Point Bending ◽  
Median Part ◽  
Glass Mat

This paper presents mechanical properties of five layers RT800 glass mat laminate impregnated with polyester resin and subjected to three-point bending tests until break. The RT800 glass mat used as reinforcement presents randomly disposed short glass fibers with 845 g/m2specific weight. From the cured plate, twenty specimens have been cut and placed on a three-point bending device and tested using a materials testing machine with servo hydraulic command. The specimens have been carried out at Compozite Ltd Brasov and the experimental tests have been accomplished at SC INAR SA Brasov and Transilvania University of Brasov. Outstanding mechanical properties of this kind of material have been found in which the specimens have suffered delamination mainly in their median part.

Stabilization of Joint Forces of the Subtalar Complex via HyProCure Sinus Tarsi Stent

2011 ◽  
Vol 101 (5) ◽  
pp. 390-399 ◽  
Author(s):  
Michael E. Graham ◽  
Rachit Parikh ◽  
Vijay Goel ◽  
Devdatt Mhatre ◽  
Aaron Matyas
Keyword(s):  
Subtalar Joint ◽  
Testing Machine ◽  
The Body ◽  
Materials Testing ◽  
Human Foot ◽  
Talocalcaneal Joint ◽  
Sinus Tarsi ◽  
Before And After ◽  
Fresh Frozen ◽  
The Mean

Background: The foot is the foundation of the body. The stability of the osseous hindfoot structure is crucial in bipedal locomotion. The subtalar joint is responsible for conversion of the rotatory forces of the lower extremities and dictates the movements of the midtarsal joints and the forefoot. In a hyperpronated foot, excessive abnormal pronation results in partial to full obliteration of the sinus tarsi. The hypothesis is that the HyProCure device will prevent obliteration of the sinus tarsi, thereby stabilizing the subtalar joint complex and eliminating the excessive forces to the proximal and distal musculoskeletal system that occur with every step. Methods: Five fresh-frozen human foot cadaver specimens that represented pathologic hindfoot and midfoot instability and partial to full obliteration of the sinus tarsi were axially compressed to 2,000 N and internally rotated by 15° to produce maximum pronation of the subtalar joint using a biaxial materials testing machine. The forces were measured across the posterior and anterior talocalcaneal joint facets before and after placement of the HyProCure stent. Results: The subtalar joint stabilized after placement of the HyProCure sinus tarsi stent. The mean ± 1 SD forces in the posterior talocalcaneal joint increased from 795.88 ± 106 N to 1,004.86 ± 72.41 N (P < 0.05, two-tailed paired t test). The mean ± SD forces at the anterior talocalcaneal joint decreased from 520.15 ± 127.18 N to 394.56 ± 73.83 N (P < 0.05), shifting the contact area posteriorly. Conclusions: Placement of the HyProCure subtalar stabilization stent in a hyperpronated foot prevents excessive talar subluxation and assists in proper distribution of the axial loads on the subtalar facet joints. (J Am Podiatr Med Assoc 101(5): 390–399, 2011)

Investigation of the Deformation Twins on the Bending Cross Section of TA2 Titanium Sheet

2020 ◽  
Vol 837 ◽  
pp. 41-45
Author(s):  
Shuai Sun ◽  
Kai Hua Liu
Keyword(s):  
Electron Backscatter Diffraction ◽  
Testing Machine ◽  
Pure Titanium ◽  
Titanium Sheet ◽  
Bending Tests ◽  
Three Point Bending ◽  
Deformation Twins ◽  
Ebsd Technique ◽  
Backscatter Diffraction ◽  
Deformation Area

In order to determine the evolution features of deformation twins for TA2 commercial pure titanium (cp-TA2), the TA2 samples were bent under different bending angles in three-point bending tests via a universal testing machine. The electron backscatter diffraction (EBSD) technique was applied to identify the grain boundaries (GBs) and twin boundaries (TBs) in the bending areas. The results reveal that the type of deformation area would effect the evolution of different deformation twins. It is inferred that the state of stress would promote the multiplication of the same type of deformation twins.

scholarly journals Novel Pilot Curriculum for International Education of Lymphoma Management Using E-Contouring

2018 ◽  
pp. 1-9
Author(s):  
Raymond B. Mailhot Vega ◽  
Omar F. Ishaq ◽  
Inaya Ahmed ◽  
Luis Rene ◽  
Beatriz E. Amendola ◽  
...  
Keyword(s):  
International Education ◽  
Radiation Oncology ◽  
Test Score ◽  
Test Evaluation ◽  
Consensus Guidelines ◽  
Non Hodgkin Lymphoma ◽  
Before And After ◽  
Radiation Oncology Group ◽  
American Society ◽  
Pilot Intervention

Purpose The International Lymphoma Radiation Oncology Group (ILROG) published consensus guidelines on the management of Hodgkin disease (HD) and nodal non-Hodgkin lymphoma (NHL), which became the most downloaded articles from International Journal of Radiation Oncology, Biology, and Physics. E-contouring workshops allow for interactive didactic sessions, allowing participants to see case-based contouring in real time. A pilot 1-hour curriculum was developed with the objective of reviewing ILROG guidelines for HD and NHL management with incorporation of e-contouring tools. This represents the first international education intervention in Spanish using e-contouring with a pre- and postintervention questionnaire. Methods A 1-hour presentation was prepared in Spanish reviewing the ILROG recommendations for HD and NHL. The review was followed by the author’s demonstration of contour creation using patients with HD and NHL prepared for the American Society for Radiation Oncology’s 2015 e-contouring lymphoma session. A five- question evaluation was prepared and administered before and after intervention. A two-tailed paired t test was performed to evaluate any significant change in test value before and after intervention. Results A total of nine quizzes were collected before and after the intervention. The average test score before the intervention was 75.6%, and the average test score after the intervention was 86.7% ( P = .051). Four students scored 100% on both the pre- and postintervention evaluations, and no student had a decrease in score from pre- to postintervention evaluation. The topic with the lowest score tested dose consideration. Conclusion A substantial but nonsignificant improvement in test evaluation was seen with this pilot curriculum. This pilot intervention identified obstacles for truly interactive didactic sessions that, when addressed, can lead to fully developed interactive didactic sessions.

Soil water dynamics after fire in a Portuguese shrubland

2006 ◽  
Vol 15 (1) ◽  
pp. 99 ◽  
Author(s):  
Joaquim S. Silva ◽  
Francisco C. Rego ◽  
Stefano Mazzoleni
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Plant Community ◽  
Root Distribution ◽  
Control Plot ◽  
The Other ◽  
Water Dynamics ◽  
Soil Water Dynamics ◽  
Surface Layers ◽  
Before And After

This paper presents a study where soil water content (SW) was measured before and after an experimental fire in a shrubland dominated by Erica scoparia L. in Portugal. Two plots were established: one was kept as a control plot and the other was burned by an experimental fire in June 2001. Measurements were taken before fire (2000), and after fire (2001, 2002, and 2003) at six depths down to 170 cm, from June to December. Measurements before fire allowed comparison of the two plots in terms of the SW differential, using 2000 as a reference. Results for 2001 showed that SW decreased less during the drying season (June–September) and increased more during the wetting season (October–December) in the burned plot than in the control plot. The magnitude of these effects decreased consistently in 2002 and 2003, especially at surface layers. The maximum gain of SW for the total profile in the burned plot was estimated as 105.5 mm in 2001, 70.2 mm in 2002, and 35.6 mm in 2003. The present paper discusses the mechanisms responsible for the increase in SW taking into account the characteristics of the plant community, including the root distribution, and the results of other studies.

Muscle glycogen availability and temperature regulation in humans

1989 ◽  
Vol 66 (1) ◽  
pp. 72-78 ◽  
Author(s):  
L. Martineau ◽  
I. Jacobs
Keyword(s):  
Skeletal Muscle ◽  
Muscle Glycogen ◽  
Temperature Regulation ◽  
Vastus Lateralis ◽  
Water Immersion ◽  
Vastus Lateralis Muscle ◽  
Glycogen Concentration ◽  
Exercise Regimen ◽  
Before And After ◽  
Muscle Groups

The effects of intramuscular glycogen availability on human temperature regulation were studied in eight seminude subjects immersed in 18 degrees C water for 90 min or until rectal temperature (Tre) decreased to 35.5 degrees C. Each subject was immersed three times over a 3-wk period. Each immersion followed 2.5 days of a specific dietary and/or exercise regimen designed to elicit low (L), normal (N), or high (H) glycogen levels in large skeletal muscle groups. Muscle glycogen concentration was determined in biopsies taken from the vastus lateralis muscle before and after each immersion. Intramuscular glycogen concentration before the immersion was significantly different among the L, N, and H trials (P less than 0.01), averaging 247 +/- 15, 406 +/- 23, and 548 +/- 42 (SE) mmol glucose units.kg dry muscle-1, respectively. The calculated metabolic heat production during the first 30 min of immersion was significantly lower during L compared with N or H (P less than 0.05). The rate at which Tre decreased was more rapid during the L immersion than either N or H (P less than 0.05), and the time during the immersion at which Tre first began to decrease also appeared sooner during L than N or H. The results suggest that low skeletal muscle glycogen levels are associated with more rapid body cooling during water immersion in humans. Higher than normal muscle glycogen levels, however, do not increase cold tolerance.

scholarly journals In Situ Coherent X-ray Diffraction during Three-Point Bending of a Au Nanowire: Visualization and Quantification

2018 ◽  
Vol 2 (4) ◽  
pp. 24 ◽  
Author(s):  
Anton Davydok ◽  
Thomas Cornelius ◽  
Zhe Ren ◽  
Cedric Leclere ◽  
Gilbert Chahine ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Reciprocal Space ◽  
X Ray Diffraction ◽  
Complex Deformation ◽  
X Ray ◽  
Three Point Bending ◽  
Atomic Force ◽  
Au Nanowire ◽  
Before And After

The three-point bending behavior of a single Au nanowire deformed by an atomic force microscope was monitored by coherent X-ray diffraction using a sub-micrometer sized hard X-ray beam. Three-dimensional reciprocal-space maps were recorded before and after deformation by standard rocking curves and were measured by scanning the energy of the incident X-ray beam during deformation at different loading stages. The mechanical behavior of the nanowire was visualized in reciprocal space and a complex deformation mechanism is described. In addition to the expected bending of the nanowire, torsion was detected. Bending and torsion angles were quantified from the high-resolution diffraction data.

scholarly journals Flexibility of K3 and ProTaper universal instruments

2011 ◽  
Vol 22 (3) ◽  
pp. 218-222 ◽  
Author(s):  
Renata Grazziotin-Soares ◽  
Flares Barato Filho ◽  
José Roberto Vanni ◽  
Susimara Almeida ◽  
Elias Pandonor Motcy de Oliveira ◽  
...  
Keyword(s):  
Mechanical Test ◽  
Testing Machine ◽  
Universal System ◽  
Universal Testing Machine ◽  
The Third ◽  
Universal Testing ◽  
Before And After ◽  
Level Of Significance ◽  
Flexible Instruments

This study used a mechanical test to evaluate the flexibility of instruments from the K3 (conicity 0.04) and the ProTaper Universal systems when they were new and after 5 uses in simulated canals. Five sets of instruments of each system were tested: K3 (15, 20, 25, 30, 35, 40 and 45) and ProTaper Universal (S1, S2, F1, F2, F3, F4 and F5). Each set of instruments was used to prepare a simulated canal and the same set of instruments was used 5 times (50 canals). The number of each subgroup represented the number of uses: 0 (control), 1, 3 and 5 uses. Before and after each use, the instruments were submitted to a mechanical flexibility test performed in a Versat 502 universal testing machine. Interactions between the instrument and the number of uses were analyzed by ANOVA and Tukey's test at a 5% level of significance. Instruments from both systems presented lower flexibility after the third use compared to the flexibility obtained after uses 0 and 1 (p<0.05), and maintained the same flexibility after the fifth use. The flexibility of instruments from the K3 system decreased with the increase of diameter, irrespective of the number of uses. Among the instruments from the ProTaper Universal system, the shaping files presented greater flexibility than the finishing files. F2 and F3 were the least flexible instruments, and F4 and F5 presented flexibility values similar to those of F1.

scholarly journals Study on the Microscopic Mechanism of Spontaneous Combustion and Oxidation Kinetics of Water-Leached Coal

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Naifu Cao ◽  
Gang Wang ◽  
Yuntao Liang
Keyword(s):  
Kinetic Model ◽  
Moisture Content ◽  
Spontaneous Combustion ◽  
Water Immersion ◽  
Combustion Process ◽  
Oxidation Kinetic ◽  
Oxidation Mechanism ◽  
Temperature Oxidation ◽  
Before And After ◽  
Spontaneous Combustion Of Coal

In this article, a series of experiments have been carried out to study the spontaneous combustion and oxidation mechanism of coal after water immersion and investigate its tendency to spontaneous combustion, analyze the difficulty of spontaneous combustion of coal samples under different water immersion conditions, and establish a kinetic model of water immersion coal oxidation (taking the Bulianta 12# coal as a case study). They rely on physical oxidation adsorption, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetry, and oil bath heating. SEM has been used to analyze the characteristics of coal pore structure under different water immersion conditions (water-saturated coal samples under different water loss conditions until the coal samples are completely dried); FTIR served to investigate the characteristics of the molecular chemical structure of the coal surface before and after the coal is immersed in water. Through programmed temperature oxidation experiments combined with FTIR analyses and gas chromatographic (GC) analysis of gaseous products, it has been possible to study the changes of molecular structure and gas products on the surface of coal samples at different temperatures and water immersion conditions. The oxidation reaction rate of the 12# coal samples of Shendong Mine’s Bulianta Mine under different water content conditions during the spontaneous combustion process has been quantitatively studied. The difficulty of spontaneous combustion of coal samples has been correspondingly addressed. A kinetic model from the perspective of oxygen consumption has been proposed. Thermogravimetry-differential scanning calorimetry (TG-DSC) has been used to analyze and study the exothermal oxidation process before and after coal immersion. From the perspective of the exothermic intensity of the coal-oxygen reaction, an oxidation kinetic model for immersed coal samples has been developed to qualitatively determine its spontaneous combustion tendency. Results have shown that the increase in the specific surface area increases the risk of spontaneous combustion, and coal samples after soaking and drying have a stronger tendency to spontaneous combustion than raw coal. The moisture content of the coal sample leading to the easiest ignition conditions is 16.05%. Regardless of the moisture content, the critical temperature is maintained at 65–75°C, and the temperature of the left coal in the goaf should be prevented from exceeding this critical value.

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