Pengaruh Variasi Bio Based Adhesive terhadap Kekuatan Peeling dan Shearing Kayu Pinus pada Adhesive Joint

The methods of joining engineering materials using adhesives is mostly implemented by using synthetic adhesives from non-renewable sources. Even though it has good joining performance, its poisonous nature and difficult to decompose naturally makes the adhesive needs to seek alternatives that are more environmentally friendly. Another reason is to support FAO campaigns for the use of environmentally friendly and biodegradable materials. One that has the potential to replace synthetic one is adhesives from natural sources such as gum rubber, jackfruit, and breadfruit. Because each natural sap has a different composition, the adhesive strength will also be different. Therefore it is necessary to examine the adhesive strength of each of these natural gums. In this research, natural adhesives (gums) and synthetic adhesives were used to joint pine wood as a test specimen. After joining, peeling and shearing tests on the specimens were carried out so that the mechanical strength of the joints for each adhesive variation was recognized. Fracture analysis was then performed to analyze the mechanism of joint failure for each adhesive variation. From this research, the highest peeling strength was obtained from rubber tree sap of 0.15 MPa, while the highest shearing strength was also obtained for rubber sap of 0.68 MPa.

Using a global tree sap flow database as ground-truth for transpiration products validation

<p>Transpiration (T) is a key driver of ecosystem energy, water and carbon flows and is tightly linked to climate and land-use change. While global models rely extensively on remotely sensed transpiration products to evaluate land-surface processes, ground-truth validation for these products does not exist. At best, data from eddy-covariance evapotranspiration is used, but the T component is partitioned based-on a set of complex assumptions, which are in themselves poorly validated for many parts of the world. Sapflow (SF) measurements allow direct quantification of tree-level T which can be used as ground-truth for T-products in forested areas. A recent global network of sapflux data, (SapFluxNet – SFN) has provided the first quality-controlled sapflow dataset at a global scale, opening up new opportunities to evaluate global T products.  Using the SFN-SF and Global Land Evaporation Amsterdam Model (GLEAM) T product, we address i) how the time course of the two products scale with one another, and ii) whether this scaling is different between days with low, median or high T/ SF within months; in addition, iii) we evaluate errors patterns of GLEAM-T in relation to SFN-SF and test whether these errors are biased by site climate or by model inputs. Our results shows GLEAM-T scales with SFN-SF, especially for days with median transpiration, but this scaling, rather than 1:1, has a slope of 0.9, which causes underestimation of SFN-SF at high GLEAM-T values. The scaling is shallower for low and high transpiration days leading to a higher bias in those days. In addition, GLEAM-T scales from SFN-SF with an offset, which compensate the shallower scaling at median values at the expense of increasing bias at extremes. Our results also show errors of GLEAM-T in relation to SFN-SF are not random but depend on the location`s climate and on the soil moisture stress factor used within GLEAM transpiration model. Our work bridges, for the first time, the scale difference between trees and pixels and shows the potential of using ground-truth SF measurements for evaluating biases and patterns in global products.</p>

HPLC and ToF‒SIMS Analyses of Toxicodendron vernicifluum Tree Sap Mixed with Other Natural Lacquers

Lacquer sap has been used by humans from antiquitywhen it was treated as a luxury item because of its desirable physical properties. In modern times, although access barriers are lower, lacquer is still considered to be rare and valuable. Thus, low quality, inexpensive Vietnamese and Myanmarese lacquers and cashew nutshell liquid are frequently added to the costly Toxicodendron vernicifluum lacquer sap from Korea, China, and Japan. However, these blended lacquers can diminish the quality of artisan works. The Toxicodendron vernicifluum lacquer saps mixed with other natural lacquers were characterized using time-of-flight secondary-ion mass spectrometry (ToF−SIMS) and high-performance liquid chromatography (HPLC). ToF-SIMS provided the chemical structure of the lacquer monomer, copolymerized dimers, trimers, etc. HPLC provided quantitative analysis of the components of a randomly mixed lacquer. These techniques can be used to control the quality of commercial lacquer sap for the Asian lacquer industry and the traditional conservation of ancient objects.

PENGARUH WAKTU PEMBAHARUAN SADAPAN POHON PINUS (Pinus merkusii) PADA UMUR BERBEDA TERHADAP PRODUKTIVITAS GETAH

Pine sap exploitation is growing because demand for pine sap in Indonesia and the world is increasing. Pine sap productivity is influenced by several factors including tapping, tree species, diameter, and age of stands. In the tapping method, one of them is the renewal time of tapping with the quarre system which is supposed to save the tapping area and get the maximum sap. This paper studies the effect of the renewal of the pine tree tapping at different ages on the productivity of the sap. The proposed method is a survey with a purposive sample determination with 3 different treatments, namely treatment A of the 3-day quarre renewal, treatment B of the 5-day quarre renewal, and treatment of the renewal of the 7-day quarre by administering stimulants. Performed at different age classes IV, VI, and VIII. Field observational data is then processed using a factorial Completely Randomized Plan analysis with two factors. The results showed that the renewal of quarre had a significant effect on the average productivity of pine tree sap at 95% confidence intervals (α = 0.05). The highest average productivity on treatment B renewal of 5 days quarre was 12.17 grams /quarre/day at age classes VI and the lowest average productivity was at treatment C of renewal of 7 days with 4.61 grams /quarre/day at age classes IV.