Far-Ching Lin

Thermal properties of interior decorating material and the sensation of cold/warm by contact II: the relations among heat flux, temperature change of material, and sensation of cold/warm by contact

The main purpose of this study was to investigate the changes in heat flux and temperature after the subjects palm was in contact with interior decorating materials. The relations among heat flux, temperature, and sensation of cold/warm during contact were studied. Ten men and ten women were selected and introduced to 21 materials for the contact test. They were in contact with the specimens for 30min without seeing them in a climate-controlled room at 25°±1°C and 65% RH. Changes in the heat flux and temperature of the specimens were determined by a heat flux meter. A sensory evaluation test was applied to evaluate the cold-warm contact. Results indicated that the heat flux and temperature increased with increasing time after the subjects palm was in contact with the specimens. The heat flux (Q30) and temperature (T30) 30min after the subjects palm contacted the specimens were greater for male subjects than for female subjects. A positive linear regression equation existed between the values for Q30 andT30, whereas a negative linear regression formula existed the sensation of cold-warm by contact (5) and the values of ln(Q1·λ). Therefore, the sensation of cold/warm by contact could be estimated simply by using the thermal physical properties of the interior decorating materials.

Thermal properties of interior decorative material and contacted sensory cold-warmth I: relation between skin temperature and contacted sensory cold-warmth.

The purpose of the study was to investigate the relation between the skin temperature of the palm and sensory cold-warmth after contact with some materials. Ten men and ten women were selected and introduced to 21 kinds of material for a contact test of 30 min without seeing the specimens in a climate-controlled room at 25‡±1‡C and 65% relative heemidity. The palm-contacted test materials and skin temperature of the palm, central fingertip, and back of the palm were measured during the experiment. A sensory evaluation test was applied to evaluate the contacted sensory cold-warmth. Results showed that the maximum temperature decrease of the fingertip (Td) was positively related to the natural logarithm of the materials specific gravity (lnρu) and to the natural logarithm of the materials thermal conductivity (lnλ). There were also negative linear relations between the contacted sensory cold-warmth (S) with lnρu and lnλ; and there was a negative linear relation betweenS withTd and betweenS with the value ofTd by λ. The thermal osmotic coefficient (b) of wood and wood-based materials ranged from 3.63 to 3.97, and the materials were qualified as good thermal insulation materials. Furthermore, there was a negative linear relation betweenS andb. Accordingly, it is possible to evaluate the contacted sensory cold-warmth relying on the basic thermal properties of material.

Effects of ACQ preservative treatment on the mechanical properties of hardwood glulam

The purpose of this study is to examine the mechanical properties of ACQ-treated glulam made from three hardwood lumbers. Two nondestructive methods, ultrasonic wave and tap tone method, were also used in this study. The results showed that the dynamic MOE and static MOE of lumbers decreased with increased ACQ preservative retention. ANOVA showed no significant difference in the MOE values of glulam between untreated and ACQ-treated group. However, it was also found that glulam made from red oak lumbers had the highest bending strength retention ratio. The shear strength of the glulam also showed similar results. Finally, no delaminating was found in all glulams after the specimens under soaked and boiled delamination tests.ZusammenfassungIn dieser Studie werden die mechanischen Eigenschaften von mit ACQ behandeltem Brettschichtholz aus drei verschiedenen Laubholzarten untersucht. Dabei wurden auch zwei zerstörungsfreie Methoden, nämlich Ultraschall- und Längsschwingungsmessung, verwendet. Die Ergebnisse zeigten, dass der dynamische und der statische Elastizitätsmodul (MOE) von Schnittholz mit zunehmender ACQ-Schutzmittelaufnahme abnahmen. Die ANOVA-Analyse ergab keine signifikanten Unterschiede zwischen den MOE Werten der unbehandelten und der behandelten Prüfkörpergruppe. Daneben hat sich gezeigt, dass die Biegefestigkeit bei Brettschichtholz aus Roteiche am geringsten beeinträchtigt war. Die Scherfestigkeit von Brettschichtholz zeigte ähnliche Ergebnisse. Delaminierungsprüfungen ergaben bei allen untersuchten Brettschichtholzgruppen keine Delaminierungen.

Effect of laminate configuration on the modulus of elasticity of glulam evaluated using a strain gauge method

The purpose of this study was to measure the strain of glulam laminae by affixing a strain gauge at the central axis of the lateral face in order to determine the effect of the configuration of the glulam. Japanese cedar and southern pine were used in the study. The strain and stress of the laminae during the bending test were recorded, and the modulus of elasticity (MOE) was calculated. The influence of the MOE of the adhesive layers was also considered. Results showed that the MOE of the laminated elements increased as its specific gravity increased, although the specific gravity was not the only factor evaluated. The MOE of glulam (Ebsg) measured by the strain gauge method was very close to the observed MOE of glulam (Eb) and a significant linear relationship was identified. The MOE (e) of laminae measured by the strain gauge method was very close to that determined (E) under the “free condition” before bonding. The difference between the modified MOE (Ebsa) and Ebsg was not significant. The MOE of glulams made of heterogeneously graded lumbers were about 23% and 31% larger than the average MOE of their laminae for Japanese cedar and southern pine, respectively. The actual neutral axis was just below the longitudinal center line. It shifted slightly within the proportional limit range and moved downward when the load increased.

The amount of wooden material in a closed room and its effect on the reverberation time

Optimal sound-absorbing materials are vital for desirable room acoustics. The effect of wood used for interior wall decoration on the acoustical environment is explored in a controlled room by changing the amount of wall wooden materials. The effect on the interior reverberation time (RT) is reported in this work. The experiment was conducted in a relatively small concrete brick house (approximate dimensions 4.6 × 3.2 × 4.2 m). Results showed that room shape and the arrangement of wooden wall decoration materials were important factors affecting the RT at different receiving positions. As the amount of wall decorating wood materials increased, the interior RT in the house decreased linearly; however, the RT at low frequencies diverged. After the analysis of covariance, all frequency variables were adjusted to the same level and a general regressive formula was developed as RT = C − 0.005 DR. Where RT is the reverberation time (s), DR is the amount of interior wood materials used (%), and the C values were constants that ranged from 0.888 to 1.606 and varied according to the different octave bands. Furthermore, it was found that the increasing influential effect with the DR showed diminishing marginal utility. This means that the influence of DR on RT was not linear, and, therefore, the marginal utility should be considered in order to use wooden panels economically.