Bending Moment Resistance of L-Shaped Two-Gusset-Plate Furniture Joints in Oriented Strandboard

Bending moment resistances of L-shaped joints connected with two gusset plates stapled on one side of joint members in oriented strandboard (OSB) were investigated. Factors were joint member material type, rail width, and number of staples. Experimental results showed that ultimate moment resistances of L-shaped, gusset-plate joints ranged from 429 to 842 N-m. Ultimate moment resistance loads of joints connected with 12 staples were 43% higher than those with 8 staples. Ultimate moment resistance loads increased as rail width increased from 152 to 203 mm with an increment of 25.4 mm, but the significance was affected by material type and number of staples. The increase in ultimate moment resistance loads of L-shaped, gusset-plate joints was not sensitive to material density profile change and density increase when 178-mm-wide or less rails were used, but the increase in moment resistances was sensitive to density increase when 203-mm-wide rails were used. Moment load-displacement curves of gusset-plate joints indicated that moment resistance loads at the ultimate point were two times their corresponding moment resistance loads at a proportional limit. The mechanical model was verified experimentally as a valid means for deriving estimation equations of moment resistances of L-shaped, gusset-plate joints in OSB

LOAD-DEFLECTION BEHAVIOR OF RATTAN CHAIR SEATS

The static and fatigue performances of seat foundations of natural rattan chairs subjected to vertical loads were investigated.  Static performance evaluation results indicate that rattan strip weaving patterns have significant effects on the vertical load carrying capacity and stiffness performance of chair seat foundations.  Herringbone and grid pattern woven seat foundations had significantly higher vertical load carrying capacity than those made with a square-corner pattern.  Square-corner pattern seat foundations yielded a softer sitting surface than herringbone and grid patterns.  Herringbone and grid pattern seat foundations can provide firmer sitting feel and good deep down support for heavier sitters.  The Burger model could be used to describe the force-deformation-time behavior of a rattan woven seat foundation subjected to vertical cyclic loading

COMPRESSIVE CREEP AND RECOVERY BEHAVIORS OF SEAT CUSHIONS IN UPHOLSTERED FURNITURE

This study investigated effects of compressive load magnitude and cover and core materials on the force-deformation-time behavior of seat cushions commonly used in upholstered furniture. Results indicated that the Burger and Kelvin models could be used to describe the creep and recovery behavior of a furniture seat cushioning system composed of foam, spring, and cover materials, respectively. Statistical analyses of experimental data indicated that the magnitude of creep loads had significant effects on the viscoelastic constants in mathematical expressions derived from the Burger model for describing the force-deformation-time behavior of the cushions evaluated. Foam cushions with coil springs had significantly greater viscoelastic constants than those without. Changing cushion cover material from leather to fabric had no significant effect on the elastic constant of tested cushion materials, but increased theviscous constant and delayed elastic-deformation-related damping constants

Tensile and Bending Moment Resistances of T-Shaped Joints in Rattan Chairs

Effects of inner fastener type, wrapping pattern and material type, and member material type on ultimate tensile and bending moment resistances of T-shaped joints in rattan chair construction were investigated based on the L9 (34) orthogonal array experimental design. The range analyses indicated that the order of impact on ultimate tensile loads of four factors was inner fastener type > wrapping pattern > member material type > wrapping material type, whereas the order of impact on ultimate bending moment was inner fastener type > wrapping material type > wrapping pattern > member material type. Analysis of variance indicated that inner fastener type affected ultimate tensile and bending moment the most among the four factors with percentages of contribution of 51.19 and 47.06 to tensile and bending moment, respectively. Optimal combinations of factors and their levels that yielded the highest ultimate tensile and bending moment resistances were identified for T-shaped, end-to-side joints in rattan materials

Formation of Nanocarbon Spheres by Thermal Treatment of Woody Char from Fast Pyrolysis Process

Influences of thermal treatment conditions of temperature, reaction cycle and time, and purge gas type on nanocarbon formation over bio-chars from fast pyrolysis and effects of thermal reaction cycle and purge gas type on bio-char surface functional groups were investigated by temperature-programmed desorption (TPD) and temperature-programmed reduction methods. Nanospheres occurred on bio-chars under the activation temperature of 700°C; more nanospheres occurred when temperature increased to 900°C. Further increase of temperature to 1100°C yielded bio-char surfaces covered with a layer of nanospheres between 20 and 50 nm. More carbon nanospheres formed by increasing thermal cycles and reaction time. Scanning electron microscope images of char surfaces showed there were fewer or no nanoparticles produced using H2 as the purge gas and they were porous. TPD results indicated that H2, H2O, CH4, CO, and CO2 in gas phases evolved from chars heated to 1000°C during the first heating cycle. H2 and CH4 peaked at 750 and 615°C, respectively. Both H2O and CO had two peaks, and CO2 had a broad peak. Only trace amounts of H2 and CO were detected in the second cycle. There was no detection for CH4, H2O, and CO2 after the second cycle

LATERAL LOAD RESISTANCE BEHAVIOR OF WOOD-PLASTIC-TO METAL SINGLE-BOLT CONNECTIONS IN OUTDOOR FURNITURE

The lateral load resistance behavior of an unconstrained, two-member, single-bolt connection in outdoor furniture applications was investigated. The unconstrained connection consisted of a wood-plastic composite (WPC) main member fastened to a metal plate as a side member through a 6.35-mm-diameter bolt without a nut or washer used. Experimental results indicated that unconstrained WPC-to-metal single-bolt connections had a significantly higher lateral resistance load if the WPC main member is loaded in the direction perpendicular to the WPC material extrusion direction than the parallel direction. Tested connections failed with bolts having one plastic hinge bent, which occurred at the interface between the metal plate and WPC main member, accompanied by the WPC main members having a compressive yield fracture at their sides close to the metal plate, but no obvious compressive mark was observed at the opposite sides. Proposed linear and yield mechanical models were verified experimentally as a valid means for deriving estimation equations of lateral resistance loads of unconstrained WPC-to-metal single-bolt connections

Effect of Coating Thickness on Sound Absorption Property of Four Wood Species Commonly Used for Piano Soundboards

Effects of polyurethane (PU) coating thicknesses (0.15, 0.30, 0.45, and 0.60 mm) on sound absorption coefficients of four wood species were investigated using the standing wave ratio method with an input sound vibration frequency range set between 125 and 4000 Hz. Wood species of four specific gravity (SG) levels were Korean spruce, European spruce, Sitka spruce, and Picea brachytyla. Experimental results indicated that PU coating can significantly increase sound absorption coefficients of higher SG species such as Sitka spruce and Picea brachytyla in all tested frequency levels, but this significant increase was not observed in lower SG species such as Korean and European spruces when tested in the frequency range from 800 to 2000 Hz. Effects of coating thickness on sound absorption coefficients of four evaluated species were found to interact with wood SG values and input sound vibration frequency ranges. Specifically, coating 0.30-mm-thick PU on Korean and European spruces tends to result in significantly lower sound absorption coefficients among the ones coated with four evaluated thicknesses when tested at the frequency less than 800 Hz, but PU coating thickness resulting in lower sound absorption coefficients on Sitka spruce and Picea brachytyla was 0.15 mm. Sitka spruce and Picea brachytyla coated with 0.30- and 0.6-mm-thick PU had lower sound absorption coefficients when tested at the frequency ranging from 1000 to 2000 Hz. When tested at the frequency greater than 2500 Hz, sound absorption coefficients of four coated species increased as coating thickness increased from 0.30 to 0.60 mm with an increment of 0.15 mm, but these four species coated with three thicker PU had significantly lower sound absorption coefficients than the ones coated with 0.15-mm-thick PU. The uncoated higher SG species tended to have lower sound absorption coefficients than uncoated lower SG ones when tested in the frequency ranging from 500 to 4000 Hz, but the differences were not found when tested under the frequency less than 400 Hz. Coating four species with different thicknesses of PU could alter their SG effects on their sound absorption coefficients

Survey of vector-borne agents in feral cats and first report of Babesia gibsoni in cats on St Kitts, West Indies

Background: As there is little data on vector-borne diseases of cats in the Caribbean region and even around the world, we tested feral cats from St Kitts by PCR to detect infections with Babesia, Ehrlichia and spotted fever group Rickettsia (SFGR) and surveyed them for antibodies to Rickettsia rickettsii and Ehrlichia canis. Results: Whole blood was collected from apparently healthy feral cats during spay/ neuter campaigns on St Kitts in 2011 (N = 68) and 2014 (N = 52). Sera from the 52 cats from 2014 were used to detect antibodies to Ehrlichia canis and Rickettsia rickettsii using indirect fluorescent antibody tests and DNA extracted from whole blood of a total of 119 cats (68 from 2011, and 51 from 2014) was used for PCRs for Babesia, Ehrlichia and Rickettsia. We could not amplify DNA of SFG Rickettsia in any of the samples but found DNA of E. canis in 5% (6/119), Babesia vogeli in 13% (15/119), Babesia gibsoni in 4% (5/119), mixed infections with B. gibsoni and B. vogeli in 3% (3/119), and a poorly characterized Babesia sp. in 1% (1/119). Overall, 10% of the 52 cats we tested by IFA for E. canis were positive while 42% we tested by indirect fluorescent antibody (IFA) for R. rickettsii antigens were positive. Conclusions: Our study provides the first evidence that cats can be infected with B. gibsoni and also indicates that cats in the Caribbean may be commonly exposed to other vector-borne agents including SFGR, E. canis and B. vogeli. Animal health workers should be alerted to the possibility of clinical infections in their patients while public health workers should be alerted to the possibility that zoonotic SFGR are likely circulating in the region

Synthesis and Characterization of Carbon Nanospheres Obtained by Hydrothermal Carbonization of Wood-derived and Other Saccharides

Carbon nanospheres were synthesized by hydrothermal carbonization (HTC) of four different carbon sources: xylose, glucose, sucrose, and pine wood derived saccharides. The obtained carbon nanospheres were characterized for particle morphology and size, and surface functional groups. Morphological and structural differences among these saccharides derived HTC carbons were clearly observed. Scanning electron microscopy images of carbon nanospheres from HTC of xylose showed uniform spherical particles with diameters around 80 nm, while carbon nanospheres obtained from glucose, sucrose, and pine-derived saccharides had particle size  in the range of 100-150 nm, 300-400 nm, and 50-100 nm, respectively. Carbon dioxide and carbon monoxide were primary gaseous phase products during the HTC process. In addition, methane, propane, hydrogen, and benzene were detected in the gas phase.Citation: Yan, Q., Li, R., Toghiani, H., Cai, Z., and Zhang, J. (2015). Synthesis and Characterization of Carbon Nanospheres Obtained by Hydrothermal Carbonization of Wood-derived and Other Saccharides. Trends in Renewable Energy, 1(2), 119-128. DOI: 10.17737/tre.2015.1.2.001