Non-intrusive Coupling: Recent Advances and Scalable Nonlinear Domain Decomposition

This paper provides a detailed review of the global/local non-intrusive coupling algorithm. Such method allows to alter a global finite element model, without actually modifying its corresponding numerical operator. We also look into improvements of the initial algorithm (Quasi-Newton and dynamic relaxation), and provide comparisons based on several relevant test cases. Innovative examples and advanced applications of the non-intrusive coupling algorithm are provided, granting a handy framework for both researchers and engineers willing to make use of such process. Finally, a novel nonlinear domain decomposition method is derived from the global/local non-intrusive coupling strategy, without the need to use a parallel code or software. Such method being intended to large scale analysis, we show its scalability. Jointly, an efficient high level Message Passing Interface coupling framework is also proposed, granting an universal and flexible way for easy software coupling. A sample code is also given.     

A modified sorting task to investigate consumer perceptions of extra virgin olive oils

A two-stage sorting task was used to probe Californian consumers’ opinions of twenty-five extra virgin olive oils based on visual assessments of the bottles. The modification of the simple sorting task aimed to encourage consumers to further discriminate products through sub-groupings of products within the groups they had already made. Sorting data were analyzed using a 3-way extension of classical multidimensional scaling called DISTATIS which explores the level of consumer agreement as well as the structure of the extra virgin olive oil products. Consumer agreements were explained by 46% of the variances found in the ways consumers sorted the bottles. Decreased amount of explained variance from the first stage to the second stage of the sorting task was observed in the olive oil product structures. Consumers were asked to describe the characteristics defining each group formed. Consumer comments were analyzed qualitatively prior to statistical analysis and were later used to understand the sorting results. Despite background differences in the usage of olive oil products, the majority of the consumers perceived the product set similarly. The two-stage sorting task allowed subjects to provide more criteria or multidimensional views of their perception of the products.     

THE CONTRIBUTION OF DEXTRINS OF BEER SENSORY PROPERTIES PART II. AFTERTASTE

We investigated the possibility that dextrins could contribute to the aftertaste of beer by being broken down to sweet sugars by salivary α-amylase after beer Ingestion. The volume, pH and temperature of beer and saliva present in the oral cavity after swallowing were measured on several subjects and found adequate for the hydrolysis of beer dextrins by salivary amylase. The in vitro hydrolysis of a 6% dextrin solution and of commercial beers by pancreatic α-amylase yielded significant amounts of glucose and maltose in addition to maltotriose. Similarly, the hydrolysis of commercial beers by human saliva produced between 2.7 and 7.4 g/litre of sweet-tasting maltose and glucose, depending on the duration of the hydrolysis (30 sec to 2 min) and the amount of saliva added to 2.5 ml of beer (0.5 or 2 ml). This much sugar, because it is produced over a period of time, may not cause a detectable sweet taste but it might partially mask the bitter aftertaste of beer.     

Adaptive multi-analysis strategy for contact problems with friction

The objective of the work presented here is to develop an efficient strategy for the parametric analysis of bolted joints designed for aerospace applications. These joints are used in elastic structural assemblies with local nonlinearities (such as unilateral contact with friction) under quasi-static loading. Our approach is based on a decomposition of an assembly into substructures (representing the parts) and interfaces (representing the connections). The problem within each substructure is solved by the finite element method, while an iterative scheme based on the LATIN method (Ladevèze in Nonlinear computational structural mechanics—new approaches and non-incremental methods of calculation, 1999) is used for the global resolution. The proposed strategy consists in calculating response surfaces (Rajashekhar and Ellingwood in Struct Saf 12:205–220, 1993) such that each point of a surface is associated with a design configuration. Each design configuration corresponds to a set of values of all the variable parameters (friction coefficients, prestresses) which are introduced into the mechanical analysis. Here, instead of carrying out a full calculation for each point of the surface, we propose to use the capabilities of the LATIN method and reutilize the solution of one problem (for one set of parameters) in order to solve similar problems (for the other sets of parameters) (Boucard and Champaney in Int J Numer Methods Eng 57:1259–1281, 2003). The strategy is adaptive in the sense that it takes into account the results of the previous calculations. The method presented can be used for several types of nonlinear problems requiring multiple analyses: for example, it has already been used for structural identification (Allix and Vidal in Comput Methods Appl Mech Eng 191:2727–2758, 2001).     

THE CONTRIBUTION OF DEXTRINS TO BEER SENSORY PROPERTIES PART I. MOUTHFEEL

The effect of dextrins on the mouthfeel of beer was assessed using instrumental and sensory techniques. By measuring the viscosity of beer with a rheogoniometer, it was shown that beer is a newtonian fluid, i.e., shear stress increased linearly with shear rate. A capillary viscometer and a rheogoniometer gave viscosity measurements that did not differ significantly for six beers ranging in viscosity from 1.1 to 2.6 centipoise (cP). In carbonated beer, the amount of dextrins needed to produce an increase in viscosity detectable by judges was 52 g/litre, which raised the viscosity by 0.31 cP as measured by capillary viscometry. Since beer usually contains between 10 and 50 g/litre of dextrins, it is concluded that dextrins are not the sole determinant of beer viscosity.     

Sensory-specific satiety: comparison of taste and texture effects

The respective contributions of taste (saltiness and sweetness) and texture (the hardness dimension) to sensory-specific satiety (SSS) were compared. Sixteen male and 16 female, young, normal-weight adults rated the pleasantness of taste, pleasantness of texture and desire to eat on visual analog scales for eight test foods, were then given one of the foods to eat ad libitum for lunch, and re-rated the same parameters for the eight foods 2 and 20 min after the end of the meal. The experimental sets of eight test foods and four lunch foods were balanced for taste quality (salty vs. sweet) and texture quality (hard vs. soft). Lunch foods were the hard and soft versions of a salty food (ham and cheese sandwich on baguette vs. white bread) or of a sweet food (apples vs. applesauce). Sensory-specific satiety was observed for both saltiness and sweetness (e.g. pleasantness of the taste of, and desire to eat sweet test foods decreased significantly after eating a sweet lunch food and similarly for salty foods), and to a lesser extent for texture (e.g. pleasantness of the texture of, and desire to eat hard test foods decreased after eating a hard lunch food and similarly for one of the soft foods). The authors conclude texture-specific satiety may be a significant component of satiety.