Shear strength and subterranean termite resistance of polystyrene impregnated sengon (Falcataria moluccana) glulam

Summary Medium density fibreboards consisting of blends of the naturally durable wood species white cypress pine (Callitris glaucophylla) and non-durable wood species were manufactured in a commercial plant and subjected to a bioassay using the subterranean termite species, Coptotermes lacteus. A board composed of 30% cypress pine, 30% slash pine (Pinus elliottii) and 40% of the naturally durable hardwood species spotted gum (Corymbia maculata) was also manufactured and bioassayed against C. lacteus. The aims were to determine (i) whether boards containing cypress pine possessed increased resistance to termite attack compared to a control manufactured entirely from non-durable wood species; (ii) the relationship between the cypress pine content of boards and their resistance (if any) to termite attack; (iii) whether the termite resistance of boards containing cypress pine could be further enhanced by the addition of spotted gum fibre. There was an inverse relationship between the cypress pine content of MDF specimens and mass losses of the specimens during the bioassay; the percentage mass losses of specimens containing 11.4, 16.2 and 34.2% cypress pine being 20.3, 13.4 and 8.8%, respectively, compared to 32.8% for the control, which consisted of non-durable slash pine (80%) and hoop pine (Araucaria cunninghamii) (20%) fibre. There was strong evidence that the inverse relationship between the cypress pine content of boards and mass losses during the bioassay was linear, although a statistically significant quadratic (curvilinear) effect was also apparent. The addition of spotted gum fibre to boards did not increase their resistance to termite attack. Cypress pine heartwood contains a variety of extractives that are either toxic or repellent to termites, and the increased termite resistance of MDF containing cypress pine compared to the control is probably due to the insecticidal effect of such chemicals on C. lacteus. The incorporation of cypress pine fibre into MDF shows promise as an alternative to chemical biocides for increasing the resistance of MDF to termites. However, the response of termites to heartwood extractives varies between species, and therefore further experimentation is needed to test the resistance of MDF containing cypress pine fibre to attack by greater range of wood destroying termites under test conditions that more closely simulate field conditions.

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Blended species plywood (white cypress pine and hoop pine): Effect of veneer thickness on susceptibility to attack by the subterranean termite Coptotermes acinaciformis

BioResources ◽

10.15376/biores.15.3.4655-4671 ◽

2020 ◽

Vol 15 (3) ◽

pp. 4655-4671

Author(s):

Christopher J. Fitzgerald ◽

Robert L. McGavin

Keyword(s):

Mass Loss ◽

Field Trial ◽

Subterranean Termite ◽

Termite Resistance ◽

Loss Measurement ◽

Visual Damage ◽

Hoop Pine ◽

Minimal Damage ◽

Cypress Pine

Blended species plywood blocks comprising of 24 different veneer configurations of naturally durable white cypress pine and non-durable hoop pine were exposed to the subterranean termite Coptotermes acinaciformis in a field trial in Australia. Three thicknesses of cypress (1.8, 2.8, and 3.0 mm) and hoop pine (1.0, 1.5, and 3.0 mm) veneer were included. Blocks were assessed for termite damage using a visual damage rating and mass loss measurement. Blocks using all hoop pine veneers received substantial damage; however, blocks that had cypress face and back veneers had improved termite resistance, particularly for the 1.0-mm hoop pine core veneers. When cypress longbands were blended with hoop pine crossbands that created alternating layers, minimal damage was sustained in the hoop pine veneers; however, the damage increased with increasing hoop pine veneer thickness. All cypress veneers received essentially no termite damage, and cypress veneer thickness did not influence the severity of hoop pine veneer damage. The trial indicated that the plywood made with hoop pine core veneers, cypress pine face, and back veneers offered some termite resistance if the hoop pine veneer thickness was kept thin. Alternating cypress and hoop pine further improved the termite resistance.

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Studi Mutu Kayu Jati di Hutan Rakyat Gunungkidul. VII. Ketahanan terhadap Rayap Tanah

Jurnal Ilmu Kehutanan ◽

10.22146/jik.34107 ◽

2018 ◽

Vol 12 (1) ◽

pp. 22

Author(s):

Ganis Lukmandaru ◽

Pito Wargono ◽

Arsy Rahman Mohammad ◽

Vendy Eko Prasetyo

Keyword(s):

Survival Rate ◽

Mass Loss ◽

Hot Water ◽

Subterranean Termite ◽

Extractive Content ◽

Natural Durability ◽

Colour Properties ◽

Termite Resistance ◽

Community Forests ◽

Teak Wood

Kayu jati telah digunakan untuk bermacam produk karena sifat ketahanan alami di atas rata-rata serta keindahan serat dan warna kayunya. Meski demikian, terdapat variasi untuk sifat ketahanan alami di antara pohon yang tumbuh di tempat tumbuh yang berbeda. Penelitian sebelumnya telah mendeskripsikan sifat kimia kayu jati tumbuh di zona ekologis yang berbeda (Nglipar, Panggang, dan Playen). Sebagai lanjutan, penelitian ini bertujuan menentukan sifat ketahahan alami terhadap rayap pada kayu jati yang tumbuh di hutan rakyat Gunungkidul dan mengeksplorasi faktor yang berkorelasi terhadap sifat tersebut yaitu sifat kimia dan warna kayu. Tujuan lainnya adalah membandingkan data yang diperoleh dengan data kayu yang tumbuh di hutan tanaman Perhutani (Randulatung). Uji pengumpanan tanpa pilihan menggunakan rayap tanah Coptotermes curvignathus terhadap sampel kayu dari tiga tempat tumbuh tersebut. Sifat warna tiap sampel diukur dengan sistem diukur menggunakan sistem CIELAB(L*, a*, b*). Data sifat kimia dan warna kemudian dihubungkan dengan kehilangan berat dan persen hidup rayap setelah 13 hari pengumpanan. Kayu gubal dan teras dari semua pohon menunjukkan aktivitas anti rayap. Perbedaan nyata diamati dalam persen hidup dalam interaksi faktor tempat tumbuh dan arah radial pohon. Sampel dari Panggang menunjukkan ketahanan alami yang lebih tinggi didasarkan persen hidup rayapnya. Selanjutnya, bagian teras dari sampel Playen dan Panggang menunjukkan aktivitas anti rayap yang lebih tinggi dibandingkan sampel dari Randublatung. Pengukuran warna menghasilkan tidak adanya beda nyata untuk kecerahan (L*) antara teras bagian luar dan dalam. Berdasar tempat tumbuhnya, sampel Playen memberikan warna kayu yang paling cerah. Apabila data di bagian teras dan gubal digabungkan, nilai kehilangan berat berhubungan positif dengan nilai kelarutan dalam air panas serta nilai kehilangan berat berhubungan negatif dengan nilai kadar ekstraktif etanol-toluena. Selain itu, nilai pH berkorelasi secara moderat dengan persen hidup rayap selama 8 hari pengamatan. Untuk sifat warna, diamati nilai kemerahan (a*) yang semakin tinggi diiringi oleh kenaikan kehilangan berat di bagian teras. Study of Teakwood Quality from Community Forests in Gunungkidul. VII. Natural Subterranean Termite ResistanceAbstractTeak wood has been used for various uses because of its excellent natural durability as well as beautiful grain and colour of its heartwood. However, variability in natural durability exists between trees of different geographical zones. The previous paper in this series reported on the chemical properties of teak wood from different zones (Nglipar, Panggang, and Playen). In this study, as a continuation, natural termite resistance of teak wood grown in community forests of Gunungkidul and the factors correlating to the termite resistance i.e. chemical and colour properties, were determined. Further, the data obtained here were compared with that of wood samples from Perhutani forest plantation (Randublatung site). No-choice termite feeding test by using a subterranean termite Coptotermes curvignathus were conducted on wood samples taken from three trees of three planted sites. The colour properties of each sample were measured using the CIELAB (L*, a*, b*) system. The chemical and colour characteristics results then were correlated with the mass loss of wood and survival rate of termites after 13 days of feeding. The heartwood and sapwood of all of the trees tested exhibited antitermitic activities. Significant differences were found in survival rate of termites due to interaction of the site and radial position. Samples from Panggang had larger termite resistance judging by its survival rate of termites. Further, the heartwood regions of Panggang and Playen sites exhibited higher antitermite activities than those of Randublatung samples. Measurements of colour showed that no significant differences were found between outer and inner heartwood parts. Samples from Playen showed the lightest on the basis of the sites. In the combined sapwood and heartwood data, mass loss was positively associated with hot-water solubility levels and negatively with ethanol-toluene extractive content. In addition, pH values moderately correlated with survival rate on 8-day observation. With regard to colour properties, it was measured that larger a* values (redness) induced larger mass loss of heartwood.

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Holding Power of Orthopaedic Screws in Metacarpal and Metatarsal Bones of Young Calves

Veterinary and Comparative Orthopaedics and Traumatology ◽

10.1055/s-0038-1633077 ◽

1992 ◽

Vol 05 (03) ◽

pp. 100-103 ◽

Cited By ~ 4

Author(s):

G. Jean ◽

J. K. Roush ◽

R. M. DeBowes ◽

E. M. Gaughan ◽

J. Kirpensteijn

Keyword(s):

Shear Strength ◽

Tensile Load ◽

Young Female ◽

Limiting Factor ◽

Holding Power ◽

Metatarsal Bones ◽

Bone Width ◽

Load To Failure ◽

Holstein Calves

SummaryThe holding power and holding power per mm bone width of 4.5 mm and 5.5 mm cortical and 6.5 mm cancellous orthopaedic screws were obtained by tensile load-to-failure studies in excised metacarpal and metatarsal bones of young female Holstein calves. Holding power and holding power per mm bone width of 6.5 mm orthopaedic screws were significantly greater than those of 4.5 and 5.5 mm orthopaedic screws in the diaphysis and metaphysis. Significant differences were not detected between holding power and holding power per mm bone width of 4.5 and 5.5 mm orthopaedic screws. The holding power was not different between metacarpi and metatarsi. The limiting factor in all tests of holding power was the shear strength of the bone. We found that 6.5 mm orthopaedic screws have the greatest holding power in the metacarpal and metatarsal bones of young calves.This study compares the holding power of 4.5 mm and 5.5 mm cortical and 6.5 mm cancellous orthopaedic screws in excised metacarpal and metatarsal bones from young female Holstein calves. We found that 6.5 mm orthopaedic screws have the greatest holding power.

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The Fully Softened Shear Strength of Lake Agassiz Clays

Geo-Congress 2020 ◽

10.1061/9780784482797.018 ◽

2020 ◽

Author(s):

Iván A. Contreras ◽

Jed D. Greenwood ◽

Aaron T. Grosser

Keyword(s):

Shear Strength ◽

Lake Agassiz ◽

Fully Softened Shear Strength

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Influence of anatomy on the adhesion performance of four wood species

Research Society and Development ◽

10.33448/rsd-v9i4.2727 ◽

2020 ◽

Vol 9 (4) ◽

pp. e31942727

Author(s):

João Gabriel Missia da Silva ◽

Pedro Nicó de Medeiros ◽

Denise Ransolin Soranso ◽

Vinicius Peixoto Tinti ◽

José Tarcísio da Silva Oliveira ◽

...

Keyword(s):

Shear Strength ◽

Specific Gravity ◽

Wood Species ◽

Tectona Grandis ◽

Glue Line ◽

Anatomical Characteristics ◽

Ray Cells ◽

Adhesion Performance ◽

Adhesion Process

The aim of this study was to evaluate the influence of anatomical characteristics on the adhesion performance of Vatairea sp., Paulownia sp., Aspidosperma populifolium and Tectona grandis wood. Specimens for anatomical, physical and mechanical analyzes were produced from tangentially oriented boards. The treatments were joint glued from pieces of the same anatomical orientation (radial and tangential), evaluated for shear strength and glue line failure. The Vatairea sp wood had the highest specific gravity (0.74 g cm-3) and the Paulownia sp (0.34 g cm-3) wood was smaller. Aspidosperma populifolium species showed the highest shear strength in the glue line in the tangential and radial faces. The anatomical variables with higher influence on the wood adhesion process were pith ray cells and especially fibers that exhibit the greatest correlation with the shear strength of the glue line.

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