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...     

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...     

Structural,Micromechanical and Tribological Characterization of Zn–Ni Coatings: Effect of Sulfate Bath Composition

Zn and Zn–Ni alloy coatings were electrodeposited on mild steel from sulfate-based bath containing Sn as additive. The effect of Ni content on the microstructure, morphology, microhardness and the tribological behavior of these coatings were studied and discussed. Adding Sn in the sulfate bath had a significant effect on the surface morphology, particularly on the Zn–8 wt% Ni coatings. By increasing the Ni concentration from 8 to 14 wt%, the X-ray patterns showed that the phase structure of Zn–Ni alloy coatings was changed from η-phase Ni₃Zn₂₂ to γ-phase Ni₅Zn₂₁. The plastic deformation and delamination were found to be wear mechanisms for the investigated coatings. While the Zn–14 wt% Ni alloys had the best wear resistance, Zn films had the most severe wear volume loss and the highest friction coefficient.     

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.     

Following Spur Gear Crack Propagation in the Tooth Foot by Finite Element Method

The objective of this study was to follow the crack propagation in the tooth foot of a spur gear by using Linear Elastic Fracture Mechanics (LEFM) and the Finite Element Method (FEM). The tooth foot crack propagation is a function of Stress Intensity Factors (SIF) that play a very crucial role in the life span of the gear. A two-dimensional quasi-static analysis is carried out using a program that determines the gear geometry, coupled with the Finite Element Code (ANSYS). The study estimates the stress intensity factors and monitors their variations on the tooth foot according to crack depth, crack propagation angle, and the crack position. An appropriate methodology for predicting the crack propagation path is applied by considering gear tooth behavior in bending fatigue. The results are used to predict/prevent catastrophic rim fracture failure modes from occurring in critical components.     

Simple analytical solution and efficiency improvement of polysilicon emitter solar cells

A simple analytical model has been developed to simulate the performance of solar cells with polysilicon contact on the front surface. The polysilicon layer with a columnar grain structure is modeled by an effective recombination velocity using a two-dimensional transport equation. A one-dimensional transport equation in the single-crystal emitter is solved, taking into account bulk recombination and non-uniformly doped emitter. Then, simple analytical expressions for the emitter reverse saturation current and light-generated current densities are obtained. The collection of the light-generated carriers in polysilicon layer has been discussed and an analytical solution of the light-generated current is derived. The results show that the polysilicon layer can result in a decrease in emitter reverse saturation current density and an increase in solar cell photovoltaic parameters. In fact, the emitter region should not be treated as a ‘dead layer’ because thin polysilicon layer front surface contact gives an improvement of about 60 mV for the open-circuit voltage, 3.6 mA/cm² for the photocurrent, and 3.9% for the cell efficiency.     

Acoustic emission characterization of damage in short hemp‐fiber‐reinforced polypropylene composites

This article aims at investigating the effects of hygrothermal aging on the damage mechanisms of short white Hemp Fiber Reinforced Polypropylene (HFRP) composites with various fiber contents (10, 20, 30, and 40 wt%). Injected molded specimens were subjected to hygrothermal aging with a relative humidity of 80% and two temperatures, 25 and 50°C. The water absorption and its effect on tensile properties of HFRP composites were investigated. The Acoustic Emission (AE) technique combined with scanning electron microscopy observations was used to identify microstructural damage events leading to overall failure of the HFRP composites. This identification according to hemp‐fiber content and hygrothermal aging was made with an unsupervised method based on a statistical multi‐variable analysis (k‐means algorithm). The AE results indicate that the quality of fiber‐matrix interface plays a major role in the damage process of HFRP composites, shown by the number of AE signals induced by the interface failure and their amplitude ranges. POLYM. COMPOS. 37:1101–1112, 2016. © 2014 Society of Plastics Engineers     

Experimental Investigation of the Interface Behavior of Balanced and Unbalanced E-Glass/Polyester Woven Fabric Composite Laminates

The aim of this work is to study the influence of weave structure on the crack growth behavior of thick E-glass/polyester woven fabric composites laminates. Two different types of laminates were fabricated: (i) balanced: plain weave (taffetas T)/chopped strand mat weave (M) [T/M]₆ and (ii) unbalanced: 4-hardness satin weave (S)/chopped strand mat weave [S/M]₇. In order to accurately predict damage criticality in such structures, mixed mode fracture toughness data is required. So, the experiments were conducted using standards delamination tests under mixed mode loading and pure mode loading. These tests were carried out in mode II using End Load Split (ELS) tests and in mixed-mode I+II by Mixed Mode Flexure (MMF) tests under static conditions. The test methodology used for the experiments will be presented. The experimental results have been expressed in terms of total strain energy release rate and R-curves. The fracture toughness results show that the T/M interface is more resistant to delamination than the S/M interface.     

Destructive polyarthritis in Behcet's disease. Apropos of a case and review of the literature]

The authors report a case of a 37 years old man with Beh?et's disease since 7 years who develops a destructive chronic polyarthritis involving wrists, hands and one knee. The parallel evolution between recurrent orogenital ulceration and arthritis added to the absence of other associated destructive rheumatism permit to link this polyarthritis to Beh?et disease. In spite of the few reports, the occurrence of destructive arthritis can't exclude absolutely the diagnosis of this affection.     

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.