Fracture Mechanics Tests in Adhesively Bonded Joints: A Literature Review

Fracture mechanics characterization tests for adhesive joints are analyzed and reviewed in order to understand their advantages and disadvantages. Data reduction techniques for analytical methods are summarized to understand the improvements implemented in each test. Numerical approaches are also used complementing tests information. Both linear and non-linear methods to obtain the fracture energy release rate are presented. Pure mode I and mode II tests are described. Simple mixed-mode tests, varying only the specimen geometry, with limited mode-mixity are also presented. Performing a wider mode-mixity range requires sophisticated apparatus that are studied in detail. There is no general agreement about the test suitability for mixed-mode fracture assessment of adhesive joints. A universal test that can easily be performed and give accurate results is essential to optimize the expensive testing at the design stage.     

Optical fibre-based micro-analyser for indirect measurements of volatile amines levels in fish

An analytical method based on optical fibre (OF) detection has been developed and validated for monitoring of trimethylamine (TMA) and dimethylamine (DMA) in fish handling environments and for non invasive assessment of fish quality.     

An overview on properties and applications of poly(butylene adipate‐co‐terephthalate)–PBAT based composites

There is growing interest in biodegradable polymers (BP), in particular poly(butylene adipate‐co‐terephthalate) (PBAT), due to environmental problems associated with the disposal of non‐biodegradable polymers into the environment. However, high production cost and low thermo‐mechanical properties restrict the use of this sustainable material, making its biodegradability advantageous only when it is decisively required. The addition of different compositions of monomers and selective addition of natural fillers have been reported as alternatives to develop more accessible PBAT‐based bioplastics with performance that could match or even exceed that of the most widely used commodity plastics. This review explores the recent progress of the applications and biodegradation of PBAT. The addition of natural fillers and its effect on the final performance of the PBAT‐based composites is also reported with respect to improving the properties of composites. The advance of polymerization reaction engineering combined with sustainable trend offers great opportunities for innovative green chemical manufacturing. POLYM. ENG. SCI., 59:E7–E15, 2019. © 2017 Society of Plastics Engineers     

Components of a Variance Model for the Analysis of Repeated Measurements in Fixed-Point Comparisons

Experimental design is a statistical tool concerned with the planning of experiments to obtain the maximum amount of information from the available resources. This tool may be applied to metrology, especially for the analysis of a large number of repeated measurements (replicates) of short-term repeatability and the medium-term and long-term reproducibilities, enabling the inclusion of these “time-dependent sources of variability” in the uncertainty budget. The realization of the International Temperature Scale of 1990 (ITS-90) scale requires that laboratories usually have more than one cell for each fixed point, for comparison on a regular basis. The calculation of the uncertainty of such comparisons is considered here, taking into account these time-dependent sources of variability. These components of the uncertainty evaluated by a Type A method are obtained by the statistical analysis of the experimental results using the components of a variance model for designs consisting of nested or hierarchical sequences of measurements, as foreseen by the mainstream GUM. An application example of a balanced nested structure in the comparison of two fixed-point cells is presented.     

Calculating SPRT Interpolation Error

Interpolation error is a major source of uncertainty in the calibration of standard platinum resistance thermometer (SPRT) in the subranges of the International Temperature Scale of 1990 (ITS-90). This interpolation error arises because the interpolation equations prescribed by the ITS-90 cannot perfectly accommodate all the SPRTs natural variations in the resistance–temperature behavior, and generates different forms of non-uniqueness. This paper investigates the type 3 non-uniqueness for fourteen SPRTs of five different manufacturers calibrated over the water–zinc subrange and demonstrates the use of the method of divided differences for calculating the interpolation error. The calculated maximum standard deviation of 0.25 mK (near \(100\,^{\circ }\hbox {C}\)) is similar to that observed in previous studies.     

Selection of formal verification heuristics for parallel execution

Functional verification is “the” major design-phase bottleneck for silicon productivity. Since functional verification is an NP-complete problem, it relies on a large number of heuristics with associated parameters (engines). With the advent of parallel processing, formal verification can be optimized by selecting the best n engines to run in parallel, increasing the chance of reaching successful termination of the verification task. In this paper, we will present a methodology to build engine estimators based on structural metrics and to select n engines to run in parallel. The methodology considers both engines’ estimated performance and engines’ correlation. Results confirmed that the methodology can be a very quick selection mechanism for parallelization of engines in order to increase the chance of running the best engines to solve the problem.     

A (solvent-free) approach to metal-free photo-catalysts for methylene blue degradation

Iranian Polymer Journal - The hazardous industrial effluent, enriched in organic dyes, produces environmental alarms of being resistant to natural degradation processes. Therefore, the development...     

3D Microstructured Surfaces Obtained by Soft‐Lithography Using Fast‐Crosslinking Elastomeric Precursors and 2D Masters

A new method for the fabrication of microstructured polymer surfaces possessing features with different 3D geometries is reported. Controlled micromolding using masters with 2D topographies and fluid elastomeric precursors with various viscosities and crosslinking kinetics yielded homogeneously structured surfaces possessing microtubes and concave and convex hemispheres with defined dimensions. This fabrication strategy does not require sophisticated 3D structuring equipment and can be extended to other materials, dimensions and geometries.     

Explaining operational modal analysis with data from an arch bridge

This tutorial paper aims to introduce the topic of operational modal analysis to non-specialists on the subject. First of all, it is stressed the relevance of this experimental technique particularly in the assessment of important civil infrastructure. Then, after a synthesis of required theoretical background, three of the most powerful algorithms for output-only modal identification are presented. The several steps of these identification procedures are illustrated with the processing of data collected on a concrete arch bridge with a span of 280 m. As the use of operational modal analysis in the context of structural health monitoring is a subject under active research, this theme is also introduced and briefly exemplified with data continuously recorded at the same bridge.     

Spatial modelling of freshwater fish in semi‐arid river systems: a tool for conservation

This paper examines the feasibility of using multivariate statistics to model fish species distribution and habitat requirements for intermittent streams in semi‐arid regions, many of which are coming under increasing pressure from water resource development schemes. The assessment was based on the geographical distribution of six endemic fish species in the Guadiana river, a semi‐arid river system in southern Iberia. Their presence was related to 20 environmental variables linked to climate, geomorphology, riparian vegetation and location in the drainage basin. These variables were collected in the field or from topographical maps to evaluate habitat suitability and to predict the presence of the species according to season. Multivariate logistic regression in a geographic information system (GIS) environment was performed to identify regions with high probability of occurrence for each species. The variables that best explained the occurrence of the species were the sample location in the drainage basin, the geomorphology and the riparian vegetation. The models presented have a high predictive power and can be used in monitoring and predicting temporal changes caused by human activities. This modelling approach can be used to predict the areas that need to be conserved to protect or rehabilitate the endangered species. Armed with this information, managers can formulate conservation measures to prevent further degradation of the stocks and possibly enhance the populations. Copyright © 2002 John Wiley & Sons, Ltd.