For the Paulownia Clone in vitro 112 hybrid to be used in the wood industry, it is necessary to know its basic properties. Its air dry density of 231 kg/m 3 is nearly 20% lower than that of Paulownia tomentosa. Its average compressive strength is 19.9 MPa, its shear strength is 4.1 MPa, the static modulus of rupture (MOR) is 32.3 MPa, and the modulus of elasticity (MOE) is 3800 MPa. Its volumetric shrinkage is 8.47%, with longitudinal 0.6%, radial 3.2% and tangential 5.0%. The ratio of tangential to radial shrinkage is very favorable, just 1.6.
This research involved the most widely used wood-species of veneers in Hungary (oak, ash, beech, cherry, and maple). The resulting changes in color produced at treatment temperatures between 80 and 200 °C in different treatment times were evaluated using the CIELab color stimulus evaluation system. For higher temperature treatments, a tight functional relationship was observed between the treatment time and the difference in color stimulus. Heat treatments within a temperature range above 160 °C produced visually perceptible results, while color change resulting from heat treatments at lower temperatures was almost imperceptible. For higher temperature treatment a tight functional relationship was observed between the difference in color stimulus and treatment time (r 2 >min. 0.84). Different tree species produced different extents of change in hue depending on the treatment parameters. Among the color components, the perceptible discoloration was mostly produced by the change in the lightness factor (L*). As the treatment temperature rose, the change in the red (a*) and yellow (b*) components was less significant regardless of the species.
Poplar and black locust plantations are widely used for production of raw materials for biofuel. In this study, the main characteristics affecting energy content were evaluated for 2-year-old plantations obtained from 3 different sites of various qualities were evaluated. The 'I-214' poplar and the black locust had smaller (16 to 21%) bark ratios, while the 'Kopecky' poplar had a higher (22 to 26%) bark gain yield. The black locust had a higher basic density than that of the poplars, which were wood (446 kg/m 3 ) and bark (402 kg/m 3 ). The higher heating value of the bark of the black locust (19.51 to 19.59 MJ/kg) and of the 'Kopecky' (19.58 to 19.86 MJ/kg) was greater than that of the wood; in the case of the 'I-214' (19.59 to 19.81 MJ/kg), the higher heating value of the wood was higher. The ash content of the bark (4.50 to 8.22%) was several times greater in the case of poplars and black locust than that of the wood (0.46 to 1.29%). In the case of the wood, the ash content increased by the degradation of the site's quality. There were remarkable differences between the black locust and the poplars, as well as the individual poplar clones among the main energetic characteristics.
<p class="p1"><span class="s1">A hazai nemesnyár anyagok értéknövelt hasznosításának a</span>z egyik lehetősége az LVL termék<span class="s1"> készítése. A nyár LVL mechanikai tulajdonságai </span>némileg elmaradnak a jelenleg kapható fenyő LVL paramétereitől. A tulajdonságok javíthatók keménylombos erősítő rétegek alkalmazásával.</p><p class="p2">Az ismertetett kutatás során óriás- és olasznyár fafajtákból készült LVL mechanikai tulajdonságait módosítottuk bükk, csertölgy, illetve bálványf<span class="s2">a erősítő furnérrétegekke</span>l. Az elkészült LVL termékek mechanikai tulajdonságait roncsolásmentes módszerekkel és statikus vizsgálatokkal határoztuk meg. A lemezek rugalmassági modulusát modellezéssel is becsültük, a furnérrétegek elasztikus tulajdonságai és feltételezett tömörödése alapján.<span class="s2"> A cikksorozat első részében a roncsolásmentesen mért és modellezett elasztikus tulajdonságokat mutatjuk be.</span></p><p class="p3">Az erősítő rétegek használatával a rugalmassági modulus értékek szignifikánsan növekedtek. Bükk esetében a javulás a várakozásnak megfelelő volt, míg csertölgy, és különösen bálványfa esetén jóval meghaladták azt, ami mutatja, hogy e furnérok erősítő rétegként történő alkalmazásában jelentős lehetőségek rejlenek. Az alkalmazott modell jól becsülte a nyár kontroll lemezek és a bükk furnérral erősített lemezek rugalmassági modulusát, azonban konzervatív becslést adott a csertölgy és bálványfa rétegek hatása tekintetében.</p>
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