Port Orford Cedars

BEST TYPE YEW FLIGHT BOW 10-lb. bow, J54n. Port Orford cedar arrow.. 60 yd,... 

In this connection, the whole procedure to perform the adiabatic oxidatively-heating test for a moisture-containing gas-permeable oxidatively-heating substance is explained in detail in Subsection 8.4.1 by taking the procedure performed for 0.3 g of the sawdust of Port Orford cedar charged in the draft cell, into which air is supplied, as an example. 

For the procedure to calculate the Tc for a heap of a moisture-containing gas-permeable oxidatively-heating substance, having some one of the several specific shapes including the class A geometries as well as an arbitrary value of r, placed in the atmosphere under isothermal conditions, refer to the concrete procedure, which is exhibited in Subsection 8.4.3, to calculate the Tc for a sawdust heap of Port Orford cedar formed into an infinite slab, 60.96 cm (2 feet) in thickness, and placed in the atmosphere under isothermal conditions. 

The values of Tc thus calculated each for the sawdust heaps of fifteen wood species, including Port Orford cedar, ranged from 118 °C for the sawdust heap of zelkova to 142 °C for that of Sitka spruce. 

Five oxidalivciy-hcating processes, of 0,3 g each of five samples of the sawdust of Port Orford cedar charged each in the draft cell, into which air is supplied, and subjected each to the adiabatic oxidatively-heating test started from each in the range of 164.8 to 173.3 C with mutual intervals of 2 K, recorded each for the time. At, required for the temperature of each sample of the sawdust to increase by the definite value of AT oi 1.25 K from the corresponding standard temperature, are presented in Fig. 85. The point marked with 0 on the time axis in Fig. 85 corresponds to the point of time s in Fig. 15 presented in Section, 3.4. 

After a thin gas-permeable silica fiber sheet has been placed on the bottom of a draft cell, i.e., the cell with which the sample cell is prepared, 0.3 g of the sawdust of Port Orford cedar, which is of course a kind of the moisture-containing gas-permeable oxidatively-heating substance, is charged in the cell. The glass jig mentioned in a footnote in Section 7.3 is used at this time to provide a thin vertical hole at the center of the sawdust charged in the cell in order to facilitate the insertion of the thermocouple into the sawdust. 0.3 g was chosen herein as the standard sample quantity in the adiabatic oxidatively-heating test performed for the sawdust of every wood species. For the procedure to prepare the sawdust of each wood species, refer to Subsection 8.2.1. 

The power supplies connected to the cold junction, the air bath, the digital D.C. microvoltmeter, the digital D.C. millivolt recorder and the two-pen strip chart recorder are then switched on, respectively. The A T pen of the two-pen strip chart recorder is, however, left on the short position until the thermal equilibrium state is nearly attained again around the sawdust of Port Orford cedar charged in the draft cell, into which nitrogen gas is supplied, and inserted into the adiabatic jacket maintained at a nominal J, of the run, 1.5 2 h after the reset of the temperature of the air bath. For the term, the A Taiff pen, refer to Subsection 4.5.4. 

After the drying time above referred to has passed, the temperature of the air bath is reset at a proper value, i.e., the nominal T of the run, by means of the temperature dial on the air bath on the basis of the oxidatively-heating property of the sawdust tested to give estimated rates of increase in temperature of 1.25 K/h in the adiabatic oxidatively-heating test, with the result that the Tj ranged from 157.4 °C for the sawdust of red lauan to 178.6 °C for that of Sitka spruce in the case of the sawdusts tested herein. As to the sawdust of Port Orford cedar, the Ts ranged from 164.8 to 173.3 °C. 

Immediately after that, the supply of nitrogen gas into the draft cell is ceased, and the supply of air into the draft cell at a flow rate of 2 cmVmin, the adiabatic control by means of the adiabatic self-heating process recorder and the record of the oxidatively-heating process, in the early stages, of 0.3 g of the sawdust of Port Orford cedar charged in the draft cell by means of the digital D.C. millivolt recorder are started, respectively. This point of time corresponds to the point s in Fig. 15 presented in Section 3.4. 

After the start of the adiabatic control, the Tam is raised automatically by the adiabatic control in order that the condition, A= T - Tam = 0, may always hold, with the result that the heat generated in the oxidatively-heating sawdust of Port Orford cedar is all accumulated in it, and, it continues to heat oxidatively at the rates depending on the value of and on the gradually increasing oxygen concentration in the atmosphere in the adiabatic jacket in the meantime, the temperature of the space in the air bath, except that in the adiabatic jacket, is maintained at the T, of the run throughout every run. 

That is, the test is interrupted as soon as the temperature of the sawdust of Port Orford cedar in the cell increases by the definite value of AT o. 25 K from the corresponding standard temperature. 

The plot of In kit versus 1/7 made for 0.3 g each of five samples of the sawdust of Port Orford cedar is shown in Fig. 117. 

Based on the result, the value of a for the sawdust of Port Orford cedar is calculated by multiplying the value of A, which is presented in Table 19, by 1,000 in the same manner as performed for the value of A of TBPB in Section 4.7. 

As an example, the concrete procedure to calculate the Tc for a sawdust heap of Port Orford cedar formed into an infinite slab, 60.96 cm (2 feet) in thickness, and placed in the atmosphere under isothermal conditions is illustrated in the present subsection. 

The heat generation data, a and b, of the sawdust of Port Orford cedar were calculated in (6) of Subsection 8.4.1 and are given in Table 21 in (1) of Subsection 8.4.4, respectively. 

On the other hand, the value of of the sawdust of Port Orford cedar was calculated at 0.17 cm /min by applying the constant-heating-rate method in Subsection 8.4.2. 

On the other hand, if the value of Tc for the sawdust heap of Port Orford cedar above referred to is assumed to be 403.67604 K or 130.52604 °C, the value of the left-hand side of Eq. (79) is calculated in the following manner. 

The values of calculated each for the sawdust heaps of fifteen wood species, including Port Orford cedar... 

The adiabatic oxidatively-heating tests for the sawdusts of fourteen wood species, other than Port Orford cedar, were also performed in the same manner as done for the sawdust of Port Orford cedar, respectively. 

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