Ming-Jer Tsai

Effects of manufacturing conditions on the adsorption capacity of heavy metal ions by Makino bamboo charcoal

The objective of this study was to investigate the effects of manufacturing conditions on the adsorption capacity of heavy metal ions by Makino bamboo charcoal. Results show that the specific surface area and iodine number of bamboo charcoal activated at 900 degrees C were larger than those of bamboo charcoal activated at 800 degrees C. The specific surface area of bamboo charcoal activated at 800 degrees C by carbon dioxide was larger than that of charcoal activated by steam. However, a contrary result was observed when the activation temperature was 900 degrees C. The total volume and proportion of micropores in bamboo charcoal activated by carbon dioxide were greater than those in the other sample groups. However, the total volume and bulk volume of meso- and macropores, and average pore diameter for bamboo charcoal activated by steam were greater than those in the other sample groups. Using 5g bamboo charcoal (10-30 mesh) with a soaking time of 24h, a better adsorption effect on Pb2+ (100%), Cu2+ (100%), and Cr3+ (88-98%) was found. However, medium frequencies were observed for the adsorption of Cd2+ (40-80%) and Ni2+ (20-60%). Very limited adsorption of As5+ was detected in this study. For the same charcoal grain sizes, the adsorption capacity of 0.5g of charcoal was better than that of 0.1g. The improved adsorption effect of the sample group activated by steam was compared with the sample group activated by carbon dioxide.

Nondestructive evaluation techniques for assessing dynamic modulus of elasticity of moso bamboo (Phyllosachys edulis) lamina

Bamboo, an extensively used material in Asia, is becoming an increasingly available structural (e.g., flooring and furniture) material in Taiwan. The bending strength and dynamic modulus of elasticity of moso bamboo (Phyllosachys edulis) laminae were investigated using ultrasonic-wave and drilling resistance techniques. The strength quality of bamboo was reduced after steaming treatment and was significantly affected by node characteristics. The transverse variations of the mean drilling resistance value (R) gradually increased outward from the bamboo cavity layer. There were very significant positive relationships among density (ju), the drilling resistance value (R), the dynamic modulus of elasticity (Eb), the modulus of elasticity (MOE), and the modulus of rupture (MOR), although the coefficients of determination were small. Combining ultrasonic-wave and drilling resistance techniques is efficient in estimating and establishing the dynamic modulus of elasticity (REb). Values of REb for moso bamboo increased with increasing ju, R, Eb, MOE, and MOR, and the relationships could each be represented by positive linear regression formulas.

Compressive strength of young Taiwania (Taiwania cryptomerioides) trees grown with different thinning and pruning treatments

Taiwania (Taiwania cryptomerioides Hay) is an important timber species in Taiwan. Growth in generally improved trees under intense silvicultural practice is so rapid that rotations or the practice of thinning trees may be as short as 20–30 years. Thus, the wood properties of young plantation trees need to be characterized to effectively use this resource. The effects of different thinning and pruning methods on the compressive strength parallel to grain of young Taiwania trees were explored. Average compressive strengths with various thinning treatments revealed the trend of no thinning > medium thinning > heavy thinning and in the pruning treatments showed the trend of medium pruning > no pruning > heavy pruning. However, most results showed no statistically significant differences among thinning and pruning treatments.

The health effects of a forest environment on subclinical cardiovascular disease and heath-related quality of life.

Background Assessment of health effects of a forest environment is an important emerging area of public health and environmental sciences. Purpose To demonstrate the long-term health effects of living in a forest environment on subclinical cardiovascular diseases (CVDs) and health-related quality of life (HRQOL) compared with that in an urban environment. Materials and Methods This study included the detailed health examination and questionnaire assessment of 107 forest staff members (FSM) and 114 urban staff members (USM) to investigate the long-term health effects of a forest environment. Air quality monitoring between the forest and urban environments was compared. In addition, work-related factors and HRQOL were evaluated. Results Levels of total cholesterol, low-density lipoprotein cholesterol, and fasting glucose in the USM group were significantly higher than those in the FSM group. Furthermore, a significantly higher intima-media thickness of the internal carotid artery was found in the USM group compared with that in the FSM group. Concentrations of air pollutants, such as NO, NO2, NOx, SO2, CO, PM2.5, and PM10 in the forest environment were significantly lower compared with those in the outdoor urban environment. Working hours were longer in the FSM group; however, the work stress evaluation as assessed by the job content questionnaire revealed no significant differences between FSM and USM. HRQOL evaluated by the World Health Organization Quality of Life-BREF questionnaire showed FSM had better HRQOL scores in the physical health domain. Conclusions This study provides evidence of the potential beneficial effects of forest environments on CVDs and HRQOL.

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.

Assessment of temperature and relative humidity conditioning performances of interior decoration materials

The purpose of this study was to explore conditioning effects on wood panels (used as interior decorative materials). We examined hourly the temperature and relative humidity (RH) in a living environment based on the data of average values from 1974 to 1990 in the Taipei area. Thirty-six interior finish materials attached to one inside surface of a 353 cu cm simulation aluminum container were used in this study. An A/V ratio (surface area/volume) of 2.86 (m−1) or various other values and the panel thickness had no significant effect on the room temperature changing ratio. The hygroscopic conditioning performances of these decorative materials were classified into four types in accordance with b values: type I (b > 0.0200) included four solid woods (unfinished), seven wood-based materials, three composite materials, and one inorganic material. Type II (0.0170 <b < 0.0199) included one solid wood, five wood-based materials, and two inorganic materials. Type III (0.0070 <b < 0.0169) included nine wood-based materials, and four inorganic materials. The RH changing ratio decreased curvilinearly with increasing interior decorative panel thickness and A/V values in a sealed container, whereas theb values increased with increasing interior decorative panel thickness and A/V values in a sealed container.

Effects of Tenon Depths and Bolt Constraint Conditions on the Mechanical Behavior of Semi-Rigid Joints of Wooden Historical Buildings

The effects of tenon depths and bolt constraint conditions on the mechanical behavior of semi-rigid joints of wooden historical buildings in Taiwan were examined. Monotonic and cyclic loading tests were performed on the joint specimens to obtain the moment-rotation relationship of wooden semi-rigid joints. The results showed that the wood joints could bear external lateral forces when they reached their yield strength and would not rupture immediately. The smaller the d/h (ratio of the tenon depth to beam height) value, the easier the joints collapsed during monotonic loading. The larger the d/h value, the larger the differences of the ultimate strengths. The tenon depth could be increased to strengthen the ultimate moment of the bolt. Comparing the experimental results and the results predicted by the Colson and Louveau model, the model with the proposed parameters could simulate the experimental results with a good accuracy, and the average absolute error was less than 7.6%.

Assessment of temperature and relative humidity conditioning performances of interior decoration materials in the Taipei area (II)

The purpose of this study was to explore the conditioning effects of wood panels (used as interior decorating materials). We examined hourly the temperature and relative humidity (RH) in a living environment based on the average values during winters from 1974 to 1990 in the Taipei area. Thirty-six interior finish materials attached to one inside surface of a 35cm3 simulation aluminum container were used in this study. An A/V value (surface area of interior decoration materials attached to container/inside volume of container) of 2.86m−1 or various other A/V values and panel thicknesses had no significant effect on the room temperature changing ratio. The hygroscopic conditioning performances of these decorative materials were classified into four types in accordance withb values: type I (b>0.0200) included four solid woods (unfinished), two wood-based materials, three composite materials, and one inorganic material. Type II (0.0170<b<0.0199) included one solid wood, eight wood-based materials, and two inorganic materials. Type III (0.0070<b<0.0169) included 11 wood-based materials and four inorganic materials. The RH changing ratio decreased curvilinearly with increasing interior decorating panel thickness and A/V values in a sealed container, whereasb values increased with increasing interior decorating panel thickness and A/V values in a sealed container.

Modified atmosphere and humidity packages for conservation of paper antiques

Modified atmosphere and humidity (MAH) agents were developed to manipulate the gas composition and humidity for controlling the foxing of paper materials during storage. Sodium ascorbate, sodium carbonate decahydrate, ferrous sulfate heptahydrate, and silica gel were selected as the basic ingredients to formulate the MAH agents that could effectively remove oxygen, release carbon dioxide, and control the relative humidity (RH). With all the MAH agents developed in our study, RH was reduced and maintained without decreasing the MAH efficiency. To evaluate the inhibition of microorganisms on antique paper by MAH agents, the properties of Wikstroemia papers were measured after accelerated aging and inoculation with Aspergillus flavus and Penicillium citrinum. Under high (90%) or low (50%) RH conditions, as long as MAH agents were used, even after 80 days, the color difference value of Wikstroemia paper was kept below 1.5 and foxing was not found. Paper packaged without MAH agents and under RH as high as 90% showed a substantial color difference in 60 days. Snowflake-like foxing was also found by ultraviolet light inspection. Wikstroemia paper inoculated with P. citrinum without an MAH agent showed a significant color difference in 80 days.

Stress Wave Tomography for the Quantification of Artificial Hole Detection in Camphor Trees (Cinnamomum camphora)

The purpose of this study was to evaluate defects/holes in trees using a stress wave tomo-graphic technique. Results revealed that there was a significant positive relationship of the residual disc diameter ratio with the stress wave velocity, and a negative relationship with a reduction in the corresponding stress wave velocity in the virtual radial direction. A difference in the mapped color and stress wave velocity between the hole area and its surrounding sound area was obvious, and when the ratio of the hole area to the cross-sectional area exceeded 2.3%, the hole was detectable by tomography. A significant positive relationship between wood density and stress wave velocity of the transverse section was found in this study. Moreover, above the fiber saturation point, stress wave velocities tended to decrease with increasing moisture contents using tomography. Experimental results could provide some vital information for detecting defect locations and sizes in trunk cross-sections.