Raw dataset of compression tests on a vegetable oil-based polyurethane foam exposed to different ageing conditions

The current dataset brings raw compression test information of a vegetable-based polyurethane foam (PUF) exposed to different temperatures over different periods of time. Such experimental dataset can provide researchers with important information in the application of numerical and data-driven simulations. Also, it saves money and time once the experimental part is already available. At total, 90 compression tests were done following the ASTM D1621-16 standard with pictures for digital image correlation (DIC) being simultaneously acquired. The 90 specimens were divided in nine different ageing conditions. The foam was considered transversely isotropic, thus, 10 specimens for each condition were divided in two groups, five specimens for direction 1 and five for direction 3, where direction 3 is the foam expansion direction. The 3D DIC results show longitudinal and transverse strains from virtual extensometers. The results are available in .TRA and .csv files for the tests and DIC outputs, respectively. Also, the dataset brings the pictures used for DIC in .TIF format. It also brings the dimensions of each specimen prior to the test in .txt format. These results provide information for the calculation of major mechanical properties that can be freely used in finite element models for different and creative ways to simulate the ageing process of a vegetable-based PUF.

Mechanical properties and energy absorption characteristics of tropical fruit durian (Durio zibethinus)

The paper presents for the first time the material properties and energy absorption capacity of durian shells with an attempt to use as an alternative sustainable material and mimic their structural characteristics to design a bio-inspired structure for protective packaging applications. A series of quasi-static compression tests were carried out to determine Young's modulus and bioyield stress of the durian shells as well as their energy absorption capacity. The mesocarp layers and thorns are interesting parts for investigating their energy absorption characteristics because they play an important role in protecting the flesh of durians during their drop impact onto the ground. The mesocarp layers of the shell were subjected to axial and lateral compression while the thorn specimens were compressed under axial loading with an increasing number of thorns. The results showed that the densification strain, plateau stress and specific energy absorption of the mesocarp layer under lateral loading is higher than that under axial loading. Furthermore, the compression tests on the thorns demonstrated that an increase in the number of thorns helped to absorb more energy and the specific energy absorption of the thorns was nearly two times higher than that of the mesocarp layer under the axial loading. In addition, the cyclic loading of the thorns showed that the extent of reversibility of deformation in the thorns decreases from 32% at the first cycle to around 10% at the 9th-cycle. Finally, the microstructure of the thorn and mesocarp layer was investigated to explain the experimental observation. The results indicated that the spherical shape associated with the thorns and mesocarp materials displayed an excellent energy absorption efficiency that can be mimicked to design an effective bio-inspired absorber for packing applications.

Detection of cellular material in lip-prints

We report on the visualization of cellular material within lip-prints using Diamond™ dye (DD). The transfer of cellular material via the lips can occur in cases of contact with food or drinking items as well as cases of alleged sexual assault involving oral contact. DD can effectively detect cellular material transferred by touch. Here we investigate if lip-prints can be detected and whether there is consistency within, or variability between, a person's propensity to shed cells within lip-prints. Ten volunteers were asked to press their lips against a glass slide with medium pressure for 15 s after not eating or drinking for at least 30 min. Both upper and lower lips were observed, and all tests were performed in five replicates, giving in total 900 observed areas. Consistency in the amount of cellular material deposited by lip-prints for each of the 10 individuals was observed, with each individual being associated with a 'lip shedder' status between the extremes of heavy and light. The majority of females shed more cells than the majority of males. No correlation was observed between the lip-prints shedder-status compared to deposition of cellular material from a thumb. Further, no correlation was observed between lip morphology and the 'lip shedder' status. Visualization of cellular material was not affected by lip-balm but was adversely affected by cosmetics such as lipstick. This technique demonstrates the visualization of deposited cells from parts of the body other than fingers and how cellular material can be visualized allowing targeted collection of DNA.

Acoustic emission analysis of the compressive deformation of iron foams and their biocompatibility study

We synthesized Fe foams using water suspensions of micrometric Fe₂O₃ powder by reducing and sintering the sublimated Fe oxide green body to Fe under 5% H₂/Ar gas. The resultant Fe foam showed aligned lamellar macropores replicating the ice dendrites. The compressive behavior and deformation mechanism of the synthesized Fe foam were studied using an acoustic emission (AE) method, with which we detected sudden localized structural changes in the Fe foam material. The evolution of the deformation mechanism was elucidated using the adaptive sequential k-means (ASK) algorithm; specifically, the plastic deformation of the cell struts was followed by localized cell collapse, which eventually led to fracturing of the cell walls. For potential biomedical applications, the corrosion and biocompatibility characteristics of the two synthesized Fe foams with different porosities (50% vs. 44%) were examined and compared. Despite its larger porosity, the superior corrosion behavior of the Fe foam with 50% porosity can be attributed to its larger pore size and smaller microscopic surface area. Based on the cytotoxicity tests for the extracts of the foams, the Fe foam with 44% porosity showed better cytocompatibility than that with 50% porosity.