On the Relationship Between J-Integral and Crack Tip Opening Displacement in Elastic-Plastic Fracture Mechanics

The relationship between J-integral (J) and crack tip opening displacement (δ), considered fundamental for elastic-plastic fracture mechanics, can be established based on prior knowledge of the constraint factor m, which depends on the work hardening exponent and the material’s yield strain. Both J and δ were simultaneously determined at fracture initiation and at different points along the resistance curves for a number of structural steels. The corresponding m values were calculated and then compared with the predictions made by different models. The results indicate that the experimentally determined m values are in fair agreement with the predictions made by ASTM over the whole range of flow parameters considered in this study. The Hutchinson-Rice-Rosengren singularity-based predictions result in overestimating m for steels considered to be of low strength and high strain hardening exponent. Predictions made by other models are predominantly higher in comparison with their experimental counterparts.     

Permutation-based finite implicative fuzzy associative memories

Implicative fuzzy associative memories (IFAMs) are single layer feedforward fuzzy neural networks whose synaptic weights and threshold values are given by implicative fuzzy learning. Despite an excellent tolerance with respect to either pasitive or negative noise, IFAMs are not suited for patterns corrupted by mixed noise. This paper presents a solution to this problem. Precisely, we first introduce the class of finite IFAMs by replacing the unit interval by a finite chain L. Then, we generalize both finite IFAMs and their dual versions by means of a permutation on L. The resulting models are referred to as permutation-based finite IFAMs (π-IFAMs). We show that a π-IFAM can be viewed as a finite IFAM, but defined on an alternative lattice structure (L,?). Thus, π-IFAMs also exhibit optimal absolute storage capacity and one step convergence in the autoassociative case. Furthermore, computational experiments revealed that a certain π-IFAM, called Lukasiewicz π_μ-IFAM, outperformed several other associative memory models for the reconstruction of gray-scale patterns corrupted by salt and pepper noise.     

Innovative criteria for economical exploitation of ornamental deposits applied the cut-off grade concept

An innovative methodology and mathematical model is developed to determine the cut-off grade of ornamental stone exploitation called cut-off quality, based on the balance between the present value and production process cost. These methodology and model is validated with excellent results in nepheline syenite quarry located in complex alkaline Monchique, Portugal.     

CFD modeling of heat transfer and flow field in a bakery pilot oven

A bakery pilot oven is modeled using computational fluid dynamics software. This approach relies on integration of an instrument into modeled geometry. The instrument is a heat flux measuring device that can be used in the industrial baking process. All three heat transfer mechanisms are considered and coupled with turbulent flow. Turbulence is taken into account via the k–ε realizable model whereas the surface-to-surface model simulates the radiation. Additionally, buoyancy forces are introduced by means of a weakly compressible formulation. The model predictions show a good qualitative agreement with the experimental measurements. A quantitative agreement was obtained to some extent. Limitations came from the difficulty to measure the temperature of the radiant surfaces of the oven. Operating conditions used are typical of bakery products and, as expected, radiation was the dominant mode of heat transfer. The integration of the instrument was useful for assessing the model. Since it is designed for industrial use, it may be a valuable tool for future challenges in the field, such as simulation of an industrial scale oven.     

Physical-Chemical Characterization and Polymorphism Determination of Two Nimodipine Samples Deriving from Distinct Laboratories

Knowing the characteristics of raw materials in pharmaceutical practice is both important and useful. Firstly, evaluating the physical-chemical properties of the substances that will be used must be the primary step for quality control in the pharmacy industry. This work aims at analyzing the physical-chemical characteristics of two nimodipine samples I and II derived from distinct laboratories through thermal analysis (DSC and TG/DTG), HPLC, crystallography, and microscopy. Thermal analysis showed that sample II was more unstable than I. Morphological differences concerning shape, size, and crystallinity of particles were visualized by scanning electron microscopy (SEM) and X-ray powder diffraction. To sum up, the techniques used in this study can be said to have been efficient in the characterization and evaluation of quality control of the raw material.     

Uncovering quality-attribute concerns in use case specifications via early aspect mining

Quality-attribute requirements describe constraints on the development and behavior of a software system, and their satisfaction is key for the success of a software project. Detecting and analyzing quality attributes in early development stages provides insights for system design, reduces risks, and ultimately improves the developers’ understanding of the system. A common problem, however, is that quality-attribute information tends to be understated in requirements specifications and scattered across several documents. Thus, making the quality attributes first-class citizens becomes usually a time-consuming task for analysts. Recent developments have made it possible to mine concerns semi-automatically from textual documents. Leveraging on these ideas, we present a semi-automated approach to identify latent quality attributes that works in two stages. First, a mining tool extracts early aspects from use cases, and then these aspects are processed to derive candidate quality attributes. This derivation is based on an ontology of quality-attribute scenarios. We have built a prototype tool called QAMiner to implement our approach. The evaluation of this tool in two case studies from the literature has shown interesting results. As main contribution, we argue that our approach can help analysts to skim requirements documents and quickly produce a list of potential quality attributes for the system.     

Architects and non-architects: differences in perception of property design

This study is an analysis of the perceptions of experts and non-experts in the building industry concerning a series of real estate promotions in the city of Valencia (Spain). Differential semantics were used to obtain a set of 7 dimensions or affective responses which users employ to assess real estate offerings. Two global evaluations were obtained, differentiating between purchase for residential or investment purposes. The fieldwork was done on a sample of 160 individuals (80 architects and 80 non-architects) who were asked to give their opinion on physical stimuli which included information from real estate promotion advertising brochures. Linear regression was used to estimate 4 predictive models to estimate overall customer assessment of a given offering based on an evaluation of different dimensions or affective responses. The results show different responses in both groups and for the two global assessment variables. Differential semantics appears to be a good instrument for measuring the subjective component of consumers’ emotional states. It is an emotional design technique which provides information on the emotions an object generates by capturing the affective meaning the user attaches to it.     

Characterization of Enterococcus faecalis-infecting phages (enterophages) as markers of human fecal pollution in recreational waters

Enterophages are a novel group of phages that specifically infect Enterococcus faecalis and have been recently isolated from environmental water samples. Although enterophages have not been conclusively linked to human fecal pollution, we are currently characterizing enterophages to propose them as viral indicators and possible surrogates of enteric viruses in recreational waters. Little is known about the morphological or genetic diversity which will have an impact on their potential as markers of human fecal contamination. In the present study we are determining if enterophages can be grouped by their ability to replicate at different temperatures, and if different groups are present in the feces of different animals. As one of the main objectives is to determine if these phages can be used as indicators of the presence of enteric viruses, the survival rate under different conditions was also determined as was their prevalence in sewage and a large watershed. Coliphages were used as a means of comparison in the prevalence and survival studies. Results indicated that the isolates are mainly DNA viruses. Their morphology as well as their ability to form viral plaques at different temperatures indicates that several groups of enterophages are present in the environment. Coliphage and enterophage concentrations throughout the watershed were lower than those of thermotolerant coliforms and enterococci. Enterophage concentrations were lower than coliphages at all sampling points. Enterophages showed diverse inactivation rates and T₉₀ values across different incubation temperatures in both fresh and marine waters and sand. Further molecular characterization of enterophages may allow us to develop probes for the real-time detection of these alternative indicators of human fecal pollution.