Bending Capacity of Middle Joints of Upholstered Furniture Frames
This study evaluates the edgewise bending moment capacity of the four most frequently used middle joints in the upholstered furniture frames. The research included the following joints: Mortise and Tenon, double Dowel, Corner Blocks and double Gusset Plates, designed in the form of middle joints and made of beech and poplar solid wood. The test results indicated that regarding the edgewise bending force, the strongest middle joint was the double dowel joint made of beech wood (1896.9 N), while the respective joint made of poplar marked quite a low value of bending force (937.2 N). The strength of wooden corner blocks was proved to be quite powerful, made either of beech wood, poplar wood or the combination of the two wood species (beech: 1881.8 N, poplar: 1237.6 N, beech-poplar: 1783.6 N). The gusset plate joint made of beech resulted in weaker values (1378.2 N), compared to the dowel and corner block joints made of beech, whereas the same joint made of poplar demonstrated very satisfying values of edgewise bending force (1471.8 N). Finally, the mortise and tenon joint appeared to have the lowest strength, both in the case of beech (1306 N) and poplar (634 N). The highest coeffi cient of elasticity (CE) derived from double gusset plate joint, made of beech. All the joints showed good elasticity, except the mortise and tenon joint made of poplar, as well as, the dowel joint made of poplar, which recorded the lowest elasticity values of all. Generally, beech wood resulted in stronger and more elastic joints compared to poplar.
The effect of adhesive type and bond line thickness on the strength of mortise and tenon joints
This study was carried out in order to determine the effects of adhesive type, bond line thickness and moisture content on the strength of mortise and tenon joints. The polyvinyl acetate (PVAc), urea-formaldehyde (UF) and animal adhesives were used, combined with three different bond line thicknesses. At the same time the effect of the moisture content of the wood was investigated by using wood material conditioned to 8%, 12%, 15% moisture contents. The results of the experiments showed that the strength difference between tight fitting and loose fitting joints was 28% if animal adhesive was used, 11% with UF adhesive and negligible with PVAc adhesive. The effect of the moisture content of the wood when the joints were assembled did not depend on the adhesive used. If 12% is taken as the standard moisture content, increasing it to 15% weakened joints by 15% and decreasing it to 8% strengthened them by 6%, irrespective of the adhesive. Test results indicate that strongest joints are obtained when a close tolerance is maintained between the tenon and mortise.
Physical Ageing of the Research Reactor Core Structural Materials Due to Neutron Irradiation Exposure: a Review
A research reactor (RR) is a  nuclear reactor that has function to generate and utilize neutron flux and radiation ionization for  research purposes and industrial applications. More than 60% of current operating RRs have  been operated for 30 years or more. As the time passes, the functional capabilities of structures,  systems and components (SSCs) of those RRs deteriorate by physical ageing, which can be  caused by neutron irradiation exposure such as irradiation induced dislocation and  microstructural changes. To extend the lifetime and/or to avoid unplanned outages, ageing on  the safety related SSCs of RRs need to be properly managed. An ageing management is a  strategy to engineer, operate, maintenance, and control SSC degradation within acceptable limits. The purpose of this study is to review physical ageing of the core structural materials of  the RRs caused by neutron irradiation exposure. In order to achieve this objective, a wide range  of literatures are reviewed. Comprehensive discussions on irradiation behaviors are limited only  on reactor vessel and core support structure materials made from zirconium and beryllium as  well as their alloys, which are widely used in RRs. It is found that the stability of the mechanical  properties of zirconium and beryllium as well as their alloys was mostly affected by the neutron  fluences and temperatures.