An interval observer for uncertain continuous‐time linear systems

To design robust interval observers for uncertain continuous‐time linear systems, a new set‐integration approach is proposed to compute trajectory tubes for the estimation error. Because this approach, the order‐preserving condition on the dynamics of the estimation error is no longer required. Therefore, synthesis methods can be used to compute observer gains that reduce the impact of the system uncertainties on the accuracy of the estimated state enclosures. The performance of the proposed approach is showcased through illustrative numerical examples.     

The pleural thickening approximation from thoracic CT scans

Multimedia Tools and Applications - The involvement of medical imaging in medical procedures plays an important role in the diagnosis and planning of a therapeutic treatment. Computerized...     

Smart-MEMS based inertial measurement units: gyro-free approach to improve the grade

Microsystem Technologies - Inertial measurement units (IMU) are essentially a combination of acceleration and rotation rate sensors, generating position and attitude information. For tactical and...     

Turkey liver: Physicochemical characteristics and functional properties of protein fractions

Turkey liver is an important edible meat by-product. However, it is generally unprocessed, underutilized and low-priced compared to mammalian livers. The present investigation was conducted to provide information on physicochemical composition and functional characteristics of turkey liver. Proximate composition (%) was: moisture (72.3 ± 1.2), protein (21.9 ± 0.6), fat (2.9 ± 1.6), carbohydrate (1.4 ± 0.7), and total ash (1.5 ± 0.1). Cholesterol, glycogen and total heme pigments (g/kg) in the turkey liver were 2.05 ± 0.06, 5.36 ± 0.01 and 2.3 ± 0.08, respectively. Contents in saturated, monounsaturated and polyunsaturated fatty acids (%) were 42.5, 14.6 and 32.6 respectively. Interestingly, turkey liver fat also contains 5% of camphor (oxygenated monoterpene). Mineral concentrations (mg/kg) in liver were: Na (817 ± 14), K (1390 ± 90), Ca (31.4 ± 0.3), Mg (23 ± 0.4), Fe (161 ± 5), Zn (40 ± 2) and Cu (34 ± 2). Liver proteins extracted at 5 or 10 g/l NaCl showed the highest foaming capacity (P < 0.05). Addition of xanthan (1-3 g/l) to liver proteins improved both foam formation and its stability (P < 0.05). Turkey liver also showed interesting emulsifying properties. The emulsion stability of liver proteins was more pronounced at high NaCl concentration (20 g/l). The highest emulsion stability was obtained at acidic or basic pH values (P < 0.05) and decreased at pH 6.     

A comparison of three turbulence models for the prediction of parallel lobed jets in perforated panel optimization

The general context of the present study is the design of high induction HVAC air diffusers by means of passive jet control. When the diffuser is a perforated panel with lobed orifices (Meslem et al. 2010), the optimization of jet induction consists in improving the orifice’s geometry, the spacing between orifices and their arrangement on the panel. In this study, the flow field of a turbulent twin cross-shaped jet is investigated numerically using the standard k-ε model, the Shear Stress Transport (SST) k-ω model and the Reynolds Stress Model (RSM). The results are compared with PIV measurements. The objective is to assess their capability and limitations to predict the significant features of twin jet flow when the flow is numerically resolved through a lobed diffuser. It is shown that the k-ε and RSM models are more appropriate for predicting potential jet core length, the change in jet centreline streamwise velocity, and flow expansion in the symmetry plane of the twin jet flow. However, these models overestimate the overall flow expansion and the jet volumetric flow rate. The SST k-ω model seems more appropriate for the prediction of such dynamic integral quantities. A high level of turbulent kinetic energy predicted by the k-ε and RSM models in the near field of jets is probably the reason for this overestimation of jet induction. The SST k-ω model would appear to be the most appropriate tool for optimizing orifice design, orifice to orifice spacing and relative orifice orientation on a perforated panel diffuser.     

Passive mixing control for innovative air diffusion terminal devices for buildings

This paper presents an innovative concept for optimized air diffusion in buildings. The method uses passive control of air jet through lobed diffusers. An analysis is done experimentally at different scales for a lobed shaped geometry. A cross-shaped jet is characterized first through an isolated orifice and then at the scale of one perforated panel. An intermediary analysis of two coalescent and a row of cross-shaped jets is also proposed. All the results lead to the same conclusion. The lobed diffuser favors the self-induction compared to a reference conventional circular perforated diffuser. The air flow induced in the case of the lobed perforated panel is in average twice as the one of the circular perforated panel. Despite the consequent gain in air induction for the lobed perforated panel flow, the streamwise maximum velocities display comparable values in the far field which signifies comparable throws for the two flows. Consequently, the presented lobed perforated panel concept can be generalized to different type of diffusers to improve mixing ventilation in buildings.     

Whey Powder, ι-Carrageenan,and Fat Interactions and Their Influence on Instrumental Texture and Sensory Properties of Turkey Meat Sausage Using a Mixture Design Approach

A 10-point simplex lattice design was used to investigate the effect of varying the ratios of whey powder, ι-carrageenan, and fat, and their interactions on instrumental texture and sensory properties of mechanically separated turkey meat sausages. Regression models have been developed and contour plots were drawn in order to better understand the global tendency of measured responses. Whey powder had a more notable influence than that of ι-carrageenan on all textural parameters as whey powder proportion increased. At a higher proportion (8 g/100 g sausage), whey powder improved essentially hardness, gel stress, and chewiness of extra low-fat sausage (formulation 3, 4.2 ± 0.3 g of fat/100 g sausage). Environmental scanning electron microscopy of the corresponding sausage showed a compact microstructure characterized by large network connections. Sensory evaluation also indicated that whey powder increased the flavor, the firmness, and the sliceability scores of mechanically separated turkey meat sausage, in comparison to the high-fat standard sausage (formulation 1, 13.2 ± 0.2 g of fat/100 g sausage).     

Complex Interval Arithmetic Using Polar Form

In this paper, the polar representation of complex numbers is extended to complex polar intervals or sectors; detailed algorithms are derived for performing basic arithmetic operations on sectors. While multiplication and division are exactly defined, addition and subtraction are not, and we seek to minimize the pessimism introduced by these operations. Addition is studied as an optimization problem which is analytically solved. The complex interval arithmetic thus defined is illustrated with some numerical examples which show that in many applications, the polar representation is more advisable.     

Set membership parameter estimation in the frequency domain based on complex intervals

This paper is devoted to set membership parameter estimation for non-linear complex-valued models. In such a context, the error between the measured data and the output model is supposed to be bounded with known prior bounds. The proposed approach is based on set inversion via complex interval analysis. A first contribution of this paper is the extension of logarithm and exponentiel functions to polar intervals. In a second part, it is shown on an engineering application devoted to thermal parameter estimation, that the proposed interval complex representation is useful.     

Lobed grilles for high mixing ventilation – An experimental analysis in a full scale model room

In the present study it is shown that jet flows from innovative rectangular air diffusion grilles with lobed ailerons ensure higher mixing in a room than baseline jets from classical rectangular air diffusion grilles with straight ailerons. The experimental approach uses time resolved and classical large scale PIV measurements.