Wyniki wyszukiwania - BazTech

1

Hues of Acer platanoides L. resulting from processes of thermal treatment with saturated steam

Dzurenda L.

Drewno : prace naukowe, doniesienia, komunikaty

|

2018

|

vol. 61, nr 202

165--176

EN

An analysis was made of the hues of the wood of Norway maple (Acer platanoides L.) resulting from processes of thermal treatment (colour modification) with saturated steam: tI = 112.5 ±2.5°C for τ = 5.5 hours (mode I), tII = 127.5 ±2.5°C for τ = 6.5 hours (mode II) and tIII = 137.5 ±2.5 °C for τ = 7.5 hours (mode III). Mode I produced a darker brown hue of Norway maple wood described with the following coordinates in the CIE-L*a*b*colour space: LI * = 77.2 ±1.8, aI * = 9.1 ±1.7, bI * = 18.9 ±1.5. Mode II led to a light brown-pink colour with the coordinates LII * = 70.9 ±1.5, aII * = 11.0 ±0.6, bII * = 18.9 ±0.8. Maple wood thermally modified in mode III acquired a unique brown-red colour with the coordinates LIII * = 63.3 ±1.9, aIII * = 11.1 ±0.5, bIII * = 19.2 ±0.6. When the temperature of the saturated steam used in the thermal treatment process is increased, and the exposure time of the wood is prolonged, the colour of the wood becomes darker. Specific hues are achieved through increases in the values of the red coordinate a* and yellow coordinate b* in the CIE-L*a*b*colour space. The irreversible changes in the colour of Norway maple wood achieved in some modes of colour modification with saturated steam broaden the possibilities for its use in the fields of construction and carpentry, as well as in art and design.

2

Modification of the color of birch wood during process of thermal treatment with saturated water steam

Dzurenda L.

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

|

2018

|

No. 104

245--251

EN

The aim of the paper is to determine the colour of birch (Betula pendula Rot.) in the CIE-L*a*b* colour space during the thermal treatment with saturated water steam at the temperature of t = 137.5 ± 2.5 °C for the time of τ = 7.5 hours. The colour of birch wood changes from pale white-brown to brown during the process of colour modification. Mentioned hue of thermally modified wood is described with the coordinates of CIE-L*a*b*colour space: L* = 56.8 ± 1.4; a* = 12.4 ± 0.5; b* = 18.3 ± 0.4. Irreversible colour change of the European ash wood resulting from the process of thermal modification with saturated water steam widen the possibility for its use in the field of construction and carpentry, design as well as in the field of art.

3

Granulometric composition of chips from the milling process of spruce on a CNC machining center

Kminiak R., Dzurenda L.

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

|

2018

|

No. 104

48--52

EN

The article deals with the granulometric composition of chips from the milling process of spruce cuttings with thickness 25mm by a single-shank cutter on CNC machining center SCM TECH Z5. Granulometric composition of chips is followed within the range of the commonly used technological conditions for the type of milling cutter such as feed speed vf = 1 to 5 m.min-1 and material removal e = 1, 3 and 5 mm. A granulometric analysis proves that more than half of the produced chips is a coarse fraction consisting of fibrous chip particles with dimensions over 1 mm. Dust fractions smaller than 500 μm form isometric grains i.e. chips having approximately the same size in all three dimensions. Inhalable dust particles, smaller than 100 μm, make a 3.8% share on average. It can be stated that there are no respirable dust particles with size less than > 10 μm.

4

Influence of moisture content of combusted wood on the thermal efficiency of a boiler

Dzurenda L., Banski A.

Archives of Thermodynamics

|

2017

|

Vol. 38, no. 1

63--74

EN

In the paper the influence of moisture content of wood on the heat losses and thermal efficiency of a boiler is analysed. The moisture content of wood has a negative effect, especially on flue gas loss. The mathematical dependence of the thermal efficiency of a boiler is presented for the following boundary conditions: the moisture content of wood 10–60%, range of temperatures of emitted flue gases from the boiler into the atmosphere 120–200 C, the emissions meeting the emission standards: carbon monoxide 250 mgm-3, fly ash 50 mgm-3 and the heat power range 30–100%.

5

Dependence of the boiler flue gas losses on humidity of wood biomass

Dzurenda L., Banski A.

Archives of Thermodynamics

|

2015

|

Vol. 36, no. 4

77--86

EN

The paper analyzes the influence of humidity of combusted wood biomass on the flue gas losses. A mathematical relation between flue gas losses of the boiler on wood biomass humidity is presented as well as temperature of flue gas emitted from the boiler into the atmosphere. The limits of model application for the humidity of wood biomass falls into the interval 10–60% whereas the range of temperatures of flue gases emitted from the boiler to the atmosphere is 120–200°C. The influence of the humidity of wood biomass has an adverse effect on increasing the extent of the boiler flue gas losses and thus inefficiency of the heat production. The increase of the wood biomass humidity from the value of 10% to 60% with the outlet temperature of flue gases from the boiler 120°C causes an increase in flue gas loss of the boiler from the value 8.37% to 12.43%, similarly the increase of flue gas loss by 200°C from 15.19% to 22.55%, or the increase of the flue gas loss by 7.36%.

6

The effect of thermal modification of ash wood on granularity and homogeneity of sawdust in the sawing process on a sash gang saw prw 15-M in view of its technological usefulness

Dzurenda L., Orlowski K. A.

Drewno : prace naukowe, doniesienia, komunikaty

|

2011

|

vol. 54, nr 186

27-37

EN

This paper presents the results of granulometric analyses of sawdust of unmodified and thermally- modified ash wood (Fraxinus exelsior L.) sawed on a narrow-kerf sash gang saw. The sawdust of dry thermally-modified ash produced in the sawing process on a frame sawing machine PRW15-M at a feed speed in the range of 0.36-1.67 mźmin-1 has chip granularity ranging from 33.5 micro m to 9.9 mm; whereas unmodified ash wood sawdust consists of chips in a granularity range from 35.6 micro m to 13.8 mm. It was observed that thermally-modified ash sawdust is finer, with a distinctly larger share of the fraction in the granularity range a = 125-500 micro m and a slightly increased share of the fraction in the range a = 32-125 ěm. Changes in mechanical characteristics of modified wood were also observed in the technological usefulness of a part of dry sawdust chip in the granularity range a = 250 micro m-2.4 mm. While the homogenous share of chips in sawdust produced in the process of sawing of dry ash wood was HSCha = 81-84 %, the demonstrated homogenous share of chips in ash sawdust formed in the process of sawing of dry thermally-modified wood was lower by 4-6 %.

PL

Przedstawiono wyniki analiz granulometrycznych trocin, drewna jesionowego niemodyfikowanego (Fraxinus exelsior L.) i modyfikowanego termicznie, otrzymanych w procesie przecinania drewna na pilarce ramowej wielopiłowej PRW15-M. Przecinanie drewna prowadzono dla dwu prędkości posuwu 0,36 mźmin-1 oraz 1,67 mźmin-1. Ziarnistość powstających trocin dla drewna jesionowego modyfikowanego termicznie zawierała się w przedziale od 33,5 micro m do 9,9 mm, podczas gdy dla drewna niemodyfikowanego ziarnistość trocin mieściła się w przedziale od 35,6 micro m do 13,8 mm. Stwierdzono, iż trociny otrzymywane z drewna modyfikowanego termicznie są bardziej miałkie, z większym udziałem frakcji o ziarnistości w przedziale a = 125 – 500 micro m, z nieznacznie większym udziałem frakcji z zakresu a = 32 – 125 micro m. Zaobserwowano również, że przydatność technologiczna trocin mieszczących się w zakresie ziarnistości a = 250 micro m – 2.4 mm dla drewna jesionowego niemodyfikowanego termicznie zawiera się w przedziale 81 – 84 %, zaś dla drewna jesionowego modyfikowanego termicznie jest mniejsza o około 4 – 6%.