scholarly journals Properties of a Laminated Wood Composite Produced with Thermomechanically Treated Veneers

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Larissa M. Arruda ◽  
Cláudio H. S. Del Menezzi
Keyword(s):  
Dimensional Stability ◽  
Mechanical Stability ◽  
Line Strength ◽  
Treated Wood ◽  
Hydraulic Press ◽  
Glue Line ◽  
Electric Resistance ◽  
Electric Resistance Heating ◽  
Temperature Levels ◽  
Two Temperature

The paper aimed at evaluating the properties of plywood made from thermomechanically treated wood veneers. Veneers from Amescla (Trattinnickia burseraefolia) wood were treated in a hydraulic press with electric resistance heating. Two temperature levels were applied, 140°C and 180°C, for 1 and 2 minutes with 2.7 N/mm2of pressure. A total of 30 plywood boards were produced, including six boards produced from untreated veneers. The results showed that the thermomechanical treatment did not have any deleterious effect on glue line strength and most of the mechanical properties of plywood made from treated veneers were improved. On the other hand, plywood made from untreated veneers presented better dimensional stability. Dimensional stability properties were most affected by the temperature of the treatment, while mechanical stability, represented by the glue line shear strength, was positively affected by temperature and duration of the treatment.

scholarly journals THE EFFECT OF RENNIN UPON CASEIN

1927 ◽  
Vol 10 (6) ◽  
pp. 987-1005 ◽  
Author(s):  
Vladimir Pertzoff
Keyword(s):  
Low Temperature ◽  
Free Enzyme ◽  
The Other ◽  
Temperature Coefficients ◽  
Temperature Levels ◽  
Two Temperature

1. The preparation and purification of paracasein was described and certain criteria for the absence of free enzyme provided for. 2. The solubility of purified paracasein in water at low temperature was studied, and found practically identical with the solubility of casein. 3. The capacity of paracasein to bind base was investigated by means of its solubility in NaOH at 5° and at 23° ± 2°C., and found to be distinctly different from that of casein. 4. At these two temperature levels paracasein had a 1.5 greater capacity to bind base than casein. The equivalent combining weights of paracasein and casein were found to stand each to the other, apapproximately, as 2 to 3. 5. This relationship suggested that the temperature coefficients of the solubility of paracasein and casein in NaOH are identical. 6. This evidence indicates that paracasein is a modification of casein, distinguishable by physicochemical means.

scholarly journals Effects of Shellac Treatment on Wood Hygroscopicity, Dimensional Stability and Thermostability

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 881
Author(s):  
Mihaela Liu ◽  
Guanglin Xu ◽  
Jianan Wang ◽  
Xinwei Tu ◽  
Xinyou Liu ◽  
...  
Keyword(s):  
Dimensional Stability ◽  
Moisture Absorption ◽  
Morphological Characteristics ◽  
Treated Wood ◽  
Wood Products ◽  
Control Group ◽  
Water Repellent ◽  
Thermoplastic Resin ◽  
Weight Percentage ◽  
Thermogravimetric Curve

Dimensional stability proves to be an important factor affecting the quality of wooden products. As a sort of crude and thermoplastic resin, shellac excreted by lac insects demonstrates water-repellent and environmental-friendly features. The research impregnated shellac with wood at room temperature and with a vacuum-pressure procedure. Efforts were made to examine how shellac treatment affected the dimensional stability, moisture absorption, chemical structure, thermostability, as well as morphological characteristics of wood. Results indicated that shellac treatment was a type of efficient solution useful in the enhancement of the dimensional stability of wood. Shellac solution had good permeability in the wood, and the weight percentage gain reached 13.01% after impregnation. The swelling coefficients of treated wood in the tangential and radial directions decreased by 20.13% and 24.12%, respectively, indicating that impregnation could improve wood dimensional stability. The moisture absorption of shellac-treated wood was reduced by 38.15% under 20 °C and 65% relative humidity. Moreover, shellac treatment significantly modified wood structure, although there were no drastic changes in the spectra. Specimens for shellac treatment ran across two decomposition peaks at 350 and 390 °C, and specimens in the control group saw one more common derivative thermogravimetric curve when the sharp peak approached 355 °C. After impregnation of shellac into wood, the shellac blocked pits and hardened on the intrinsic layer of the wood for fear of hygroscopicity. The practice was applicable to a variety of wood products, such as buildings, furniture, and landscape architecture.

Application of Electric Resistance Heating Method on Titanium Hot Forming at Industrial Scale

2016 ◽  
Vol 41 (11) ◽  
pp. 4441-4448 ◽  
Author(s):  
Fahrettin Ozturk ◽  
Remzi Ecmel Ece ◽  
Naki Polat ◽  
Arif Koksal ◽  
Zafer Evis ◽  
...  
Keyword(s):  
Hot Forming ◽  
Industrial Scale ◽  
Resistance Heating ◽  
Electric Resistance ◽  
Heating Method ◽  
Electric Resistance Heating

The Improvement of Durability of Marine Wood with Polymer and its Mechanism

2009 ◽  
Vol 79-82 ◽  
pp. 1021-1024 ◽  
Author(s):  
Yong Feng Li ◽  
Yi Xing Liu ◽  
Xiang Ming Wang ◽  
Xiu Rong Li
Keyword(s):  
Porous Structure ◽  
Dimensional Stability ◽  
Cell Walls ◽  
Treated Wood ◽  
Untreated Wood ◽  
Decay Resistance ◽  
Hydroxyl Group ◽  
Alkali Resistance ◽  
Hydroxyl Groups ◽  
Marine Corrosion

In order to improve the durability of marine wood against the long-term marine corrosion, the study explores to use two bifunctional reagents, maleic anhydride (Man) and glycidyl methacrylate(GMA), to react with wood by impregnating them into the porous structure of wood and further initiating them to polymerize with an initiator, AIBN, through a heat process. After the above modification, the durability of the marine wood treated with polymer was tested, and its mechanism was further analyzed as well. The testing results of the durability show that the acid resistance, the alkali resistance, the decay resistance against marine borers and the dimensional stability of the treated wood increases by 2.02 times, 12.39 times, 4.96 times and 3 times over untreated wood, respectively; and its Anti Swelling Efficiency (ASE) for dimensional stability reaches 53%, which almost equals the value of the wood treated by PEG-1500 under the same condition, while its leachability resistance is greatly higher than wood treated by PEG-1500. The analysis result with FTIR indicates that Man and GMA both react with wood, and Man reacts with the hydroxyl group of wood cell walls by its anhydride group, and GMA polymerizes in the porous structure of wood. The charactering result with SEM reveals that the resultant polymer fills in wood cell lumina as a solid form, which contacts tightly the wood cell walls without obvious gaps. The greatly reducing amount of hydroxyl groups after the reaction and the heavy jamming channels for water and marine borers approaching to wood cell walls both contribute to the improving durability of the modified wood.

scholarly journals Improved Hydrophobicity and Dimensional Stability of Wood Treated with Paraffin/Acrylate Compound Emulsion through Response Surface Methodology Optimization

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 86 ◽  
Author(s):  
Jun Jiang ◽  
Yupeng Chen ◽  
Jinzhen Cao ◽  
Changtong Mei
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Dimensional Stability ◽  
Treatment Time ◽  
Treated Wood ◽  
Good Prediction ◽  
Water Contact ◽  
Correlation Models ◽  
Acrylate Emulsion ◽  
Emulsion Concentration

Wood treatment was conducted by paraffin/acrylate compound emulsion. Response surface methodology (RSM) was applied for modeling and to determine the relationship between hydrophobicity and influencing factors. The results showed that the paraffin emulsion concentration and acrylate emulsion percentage had significant influences on water absorption (WA) and mass percentage gain (MG). The WA decreased obviously with increasing acrylate emulsion percentage. The correlation models for WA and MG showed a good prediction due to the straight-line distribution in the normal probability plot of residuals. The optimal conditions (5.57% paraffin emulsion concentration, 20% acrylate emulsion percentage, and 10 min treatment time) provided by RSM were acceptable for predicting the MG and WA. Compared to untreated (66°) and paraffin emulsion treated wood (94°), the wood treated by compound emulsion showed the highest water contact angle (133°) and better dimensional stability. This could be ascribed to a synergistic effect (bulking effect and filling effect) provided by paraffin and acrylate, which could form a completely hydrophobic film in wood.

Optimal Control of Solar Heating and Off-Peak Energy Storage Installations

1983 ◽  
Vol 105 (1) ◽  
pp. 50-57
Author(s):  
G. B. Winn ◽  
R. C. Winn
Keyword(s):  
Storage Systems ◽  
Control Strategies ◽  
Solar Heating ◽  
Electric Resistance ◽  
Cooling Systems ◽  
Heating Systems ◽  
Peak Energy ◽  
Electric Resistance Heating ◽  
Utility Cost ◽  
The Cost

It is well known that the widespread use of solar heating or cooling systems could lead to an increase in the cost of supply of power by the electric utilities. However, it is also recognized that by using appropriate control strategies in these systems the cost of supply may be reduced relative to that of electric resistance heating systems. Control strategies for solar heating systems and for off-peak heat storage systems have been developed and investigated in terms of utility cost of supply for the year 1990. This paper includes a discussion of results obtained for off-peak storage systems, solar heating systems, and combined solar and off-peak systems for the area served by Public Service Co. of New Mexico.

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