Автор: Neno Trichkov
- COMPUTATION OF THE AVERAGE WOOD TEMPERATURE AND THE RATE OF ITS CHANGE DURING UNILATERAL HEATING OF FLAT SPRUCE DETAILS BEFORE THEIR BENDING
An approach for the computation of the average mass temperature of the wood and the rate of its change during unilateral heating of flat wood details aimed at their plasticizing in the production of curved outside parts for corpses of stringed music instruments, has been suggested. The approach is based on the numerical integration of the solutions of a linear model for the calculation of the non-stationary 1D temperature distribution along the thickness of subjected to unilateral heating flat wood details.
Ключови думи: average mass temperature, rate of change in average temperature, spruce details, unilateral heating, plasticizing
- CHARACTERISTICS OF THE TRUNKS OF SCOTS PINE (PINUS SYLVESTRIS) FOR PRODUCTION OF SOLID WOOD MATERIALS
The results from the studies on the dimensional and qualitative characteristics of model trunks of Scots pine have been presented in this report. The following dimensional characteristics: diameter, length and taper have been determined. The presence, type and dimensions of knots on the outer surface of the tree trunks and inside the wood have been determined. The presence of decay, spiral grain and other defects of wood and trunk shape have been established. The results have been analysed and relations to the existing standards, possible application of wood and requirements to the solid wood materials have been made. Relevant methods and techniques for efficient processing have been suggested.
Ключови думи: Scots pine (Pinus sylvestris), trunks, dimensional and qualitative characteristics, solid wood materials
- COMPUTATION OF THE HEAT FLUX NEEDED FOR UNILATERAL WARMING UP OF FLAT SPRUCE DETAILS BEFORE THEIR BENDING
An approach for the computation of the heat flux, which is needed for warming up of flat wood details during unilateral heating aimed at their plasticizing in the production of curved outside parts for corpses of stringed music instruments, has been suggested. The approach is based on the numerical integration and differentiation of the solutions of a linear model for the calculation of the non-stationary 1D temperature distribution along the thickness of subjected to unilateral heating flat wood details. The paper presents solutions of the model concerning the non-stationary change in the specific heat flux needed for warming up of flat spruce details with thicknesses of 6, 8 and 10 mm during their unilateral heating at temperatures of the electrically heated metal band equal to 100, 120, and 140 oC.
Ключови думи: unilateral heating, flat wood details, heat flux, plasticizing, bending
- TRANSFORMATION OF TWO MUTUALLY CONNECTED MODELS FOR CONVECTIVE HEATING OF WOOD DETAILS BEFORE THEIR LACQUERING IN A FORM, SUITABLE FOR PROGRAMMING
Using the explicit form of the finite-difference method, two suggested by the authors mutually connected mathematical models have been transformed in a form, suitable for programming. For the numerical solution of the transformed models, a software program has been prepared in the calculation environment of Visual Fortran Professional. With the help of the program, the 1D distribution of the temperature along the thicknesses of flat oak details and of their carrying transport rubber band with hw = 16 mm, lw = 0.6 m, u = 0.08 kg.kg-1, hB = 4 mm,
bB = 0.8 m, and t0 = 20 oC, during unilateral convective heating for a period of 10 min at tha = 100 oC, vha = 2 m·s-1, 5 m·s-1, 8 m·s-1, and tnha = 20 ºC in order to ensure suitable thermal conditions for the subsequent details’ lacquering has been calculated, visualized and analyzed.
Ключови думи: oak details, unilateral convective heating, lacquering, carrying rubber band
- QUALITY CHARACTERISTICS OF DOUGLAS FIR STEMS (Pseudotsuga menziesii) FOR THE PRODUCTION OF MASSIVE WOOD MATERIALS
The expansions of the raw material base for solid wood materials production are particularly important in terms of wood deficit and increased consumption. The aim is to use solid wood materials production like replacement wood, which doesn’t deteriorate the performance of the finished products, as well as technical and economic production parameters. The Douglas fir (Pseudotsuga menziesii) is non popular wood species for Republic of Bulgaria. The studies for our country show that this tree species well adapted in these conditions, particularly in areas with high humidity. This gives reason to believe that this tree species is perspective for the production of solid wood materials.
This report presents the results of studies about the size and quality characteristics of Douglas fir stems.
Ключови думи: Douglas fir (Pseudotsuga menziesii), trunks, dimensional and quality characteristics, solid wood materials