Glue Area Research Articles

Adhesive and mechanical properties of the glue produced by 25 Drosophila species

Drosophila glue, a bioadhesive produced by fly larvae to attach themselves to a substrate for several days, has recently gained attention for its peculiar adhesive and mechanical properties. Although Drosophila glue production was described more than 50 years ago, a general survey of the adhesive and mechanical properties of this proteinaceous gel across Drosophila species is lacking. To measure adhesion, we present here a protocol that is robust to variations in protocol parameters, pupal age and calculation methods. We find that the glue, which covers the entire pupal surface, increases the animal rigidity and plasticity when bound to a glass slide. Our survey of pupal adhesion in 25 Drosophilidae species reveals a wide range of phenotypes, from species that produce no or little glue and adhere little, to species that produce high amounts of glue and adhere strongly. One species, D. hydei, stands out from the rest and emerges as a promising model for the development of future bioadhesives, as it has the highest detachment force per glue area and produces relatively large amounts of glue relative to its size. We also observe that species that invest more in glue tend to live in more windy and less rainy climates, suggesting that differences in pupal adhesion properties across species are shaped by ecological factors. Our present survey provides a basis for future biomimetic studies based on Drosophila glue.

Influence of laminate direction and glue area on in-plane shear modulus of cross-laminated timber

The use of cross-laminated timber (CLT) in constructing tall buildings has increased. So, it has become crucial to get a higher in-plane stiffness in CLT panels. One way of increasing the shear modulus, G, for CLT panels can be by alternating the layers to other angles than the traditional 0° and 90°. The diagonal compression test can be used to measure the shear stiffness from which G is calculated. A general equation for calculating the G value for the CLT panels tested in the diagonal compression test was established and verified by tests, finite element simulations and external data. The equation was created from finite element simulations of full-scale CLT walls. By this equation, the influence on the G value was a factor of 2.8 and 2.0 by alternating the main laminate direction of the mid layer from the traditional 90° to 45° and 30°, respectively. From practical tests, these increases were measured to 2.9 and 1.8, respectively. Another influence on the G value was studied by the reduction of the glue area between the layers. It was shown that the pattern of the contact area was more important than the size of the contact area.

Shear Block Test Performance of Melunak and Mengkulang Parallel to Glueline

This experimental research is conducted on shear strength performance of glue laminated timber parallel to glue line using Malaysian tropical hardwood Melunak and Mengkulang. The objective of this research was to determine the shear strength values of Melunak and Mengkulang with the observation and comparison of the wood and glue failure percentage of both species. Total 30 numbers of wood specimens which; 15 numbers of wood for Melunak and 15 numbers of wood Mengkulang. The block specimen dimension was 50x50x50mm, then tested using a shear block fixtures and Universal Testing Machine (UTM). The Malaysian Standard, MS758:2001 was used in conducting shear block test and to obtain the shear strength values for both specimen. Both wood tested specimen results in 9.05% different in its shear strength values, where Melunak average shear strength was higher 0.92N/mm2 than Mengkulang. Test result of shear failure to grain direction in both specimen shows that failure occurred in wood was due to wood surface area. The Melunak average percentage failure of wood and glues area 93.7% and 6.3% respectively. While for Mengkulang average failure percentage for wood and glue area were 89.7% and 10.3% respectively. The difference in result of wood failure of both specimen area directly related to the density of specimens, in which Mengkulang wood has a higher density than Melunak. Both specimens reached to its minimum shear strength capacity that was about 6N/mm2 set by the Malaysian standard MS758:2001. Both Melunak and Mengkulang wood tested specimen results in 9.05% different in its shear strength values, where Melunak average shear strength is higher about 0.92N/mm2 than Mengkulang.

Making a semi-convex Focus area in a Focus+Glue+Context map, considering map visibility and transport access points

We previously implemented the Focus+Glue+Context map system EMMA that provides local detailed data in Focus, global context data in Context, and connection data between both in the same view. Introducing the Glue area between Focus and Context makes it possible to provide uniform scaling for the two latter areas. This paper enhances EMMA through the implementation of a Focus creation function that considers transportation access points, such as stations and bus stops. The enhanced EMMA searches a route from the current location to the transportation access point, and allows users to identify the spatial relationship between the various locations in a small-scale Context, and view the route from the current location to the transportation access points in a large-scale Focus. However, if Focus is too large because of unnecessary areas used to identify the route, some parts of Context might be hidden by Focus. The proposed system solves this problem by implementing the following functions: (1) it searches stations that are adjacent to the current location and makes a semiconvex Focus that includes the current location and those stations in order for Focus to include really necessary areas. (2) It reduces Focus distortion by setting a fixed point as the center of the Focus area. (3) It smoothens the Focus shape in order to improve visibility in the Glue area. We developed a prototype of the proposed system that implements these functions.

Factors in the adhesion strength of polymers toward a solid substrate

The true adhesion is looked upon as the sum of the experimentally determined strength of the glued area, internal stresses, and unaccountable technological losses (unrealized contacts). It has been established that the internal stresses do not depend on the value of the adhesion strength.

Calculation of errors in strain-gauge measurements

In many instances when measuring strains in components with a low tensile stiffness (plastics, reinforced rubber, etc.), it becomes necessary to take into account the possible errors due to the stiffening effect of strain gauges over their glued area. This error can be accounted for by applying the deformation distortion coefficient whose value can be determined from (11). For the practical application of this formula it is necessary to know the stiffness W of strain gauges as well as the elasticity constants of the component. The stiffness of strain gauges can be determined by a simple method, described in the article.