Using the job-exposure matrix for elaborating job histories.

A first software (JHS) for the elaboration of job histories oriented toward risks was designed and results published In an article "A software for the elaboration of Job Histories". This article presents a second software (JES), based on the use of a job-exposure matrix designed for one company. The matrix is essentially a database, an organized gathering of information concerning the company. The two softwares are inter-faced and both run on a PC. When properly exploited, the two softwares can serve as an asset for epidemiological studies dealing with occupational health.     

Thin‐film encapsulated white organic light top‐emitting diodes using a WO3/Ag/WO3 cathode to enhance light out‐coupling

An alternative design of a semitransparent cathode for top‐emission white‐fluorescent organic light‐emitting diodes (OLEDs) has been investigated. The scope of this study was to improve the luminance of OLEDs used for displays while keeping the current density versus voltage characteristic unchanged for addressing purposes. The use of an optical simulation tool allowed the optimization of the tri‐layer cathode WO₃/Ag/WO₃ to increase the light out‐coupling coefficient of the device leading to an increased white emission compared with a reference device with a Ca/Ag cathode. An increase of ~40% in luminance has been calculated by simulation and experimentally confirmed. The p‐i‐n OLED structure underneath the tri‐layer cathode allowed an efficient injection of electrons independently from the work function of WO₃. The WO₃/Ag/WO₃ cathode has been also confirmed to be compatible with the atomic layer deposition technique for thin film encapsulation. Finally, lifetime measurements up to 600 h have been carried out to quantify the enhancements induced by the new cathode compared with the control device. It has been found that lifetimes of both cathode architectures are similar on this time scale, while the WO₃/Ag/WO₃ cathode shows a lower voltage drift versus aging.     

Energy Based 3D Autopilot for VTOL UAV Under Guidance & Navigation Constraints

Motion control design plays a crucial role in autonomous vehicles. Mainly, these systems operate in conditions of under-actuation, which make the control a serious task especially in presence of practical constraints. The main objective within this paper is to ensure the tracking of 3D reference trajectory overcoming some of the issues related to the control of multi-rotor vehicles (such as underactuation, robustness, limited power, accuracy, overshoot, etc.). Therefore, a control scheme for Vertical Take Off and Landing (VTOL) multi-rotor Unmanned Aerial Vehicle (UAV) is designed, applying the Interconnection and Damping Assignment-Passivity Based Control (IDA-PBC) technique. As reference model based technique, the control specifications are readily met by fixing a desired dynamic model, which is a major advantage of the technique. Moreover, a port ?controlled Hamiltonian representation is exploited in order to point out the physical properties of the system such as its internal energy. This latter is exploited, as a fitness function for an optimization algorithm, in order to decrease the consumed energy especially at the take-off step and allows the tuning of the controller parameters. The numerical simulations have shown satisfactory results that support the claims using nominal system model or disturbed model. The designed controller has been implemented on a real vehicle for which one demonstrates, in an indoor area manipulation, the effectiveness of the proposed control strategy.     

Investigation of Heat‐Induced Degradation of Virgin Olive Oil Using Front Face Fluorescence Spectroscopy and Chemometric Analysis

A simple setup using a 365‐nm light‐emitting diode coupled to a USB spectrometer through an optical fiber, in a front‐face fluorescence configuration, was used to investigate the heat‐induced deterioration of virgin olive oil at different heating temperatures and times. The samples were heated for 30, 60, 120 and 180 min for every temperature setting of 140, 160 and 180 °C, respectively. Two important results are reported in this article. First, a neo‐formed compound around 665 nm due to the degradation of chlorophyll was observed. This new peak was attributed to pyropheophytins. The second result showed an important rise of the peak around 489 nm, which corresponded to the oxidation products. The correlation obtained between the peroxide value and the 489 nm peak using principal component analysis revealed the mechanism of the oxidation process. It further showed that the peak around 489 nm is a direct consequence of the degradation of hydroperoxide.     

Optimum design of cam-roller follower mechanism using a new evolutionary algorithm

Selection of tooling to perform specific operations like drilling and milling on ceramic materials using rotary ultrasonic machining process is an important aspect to meet stringent dimensions on workpiece as well as intended performance of tool. This phenomenon is more critical for micro rotary ultrasonic machining. In the present study, an effort was made to do micro drilling operation of Ø0.3 mm tool with varying geometry, having different wall thicknesses and abrasive grain sizes using design of experiments. The effect of tool-based parameters like grain size and wall thickness has been studied on axial cutting force, radial cutting force, tool wear, edge chipping area and taper. After examining axial and radial cutting forces, it has been concluded that lower wall thickness (80 μm) tool is good for drilling operation; and higher wall thickness (100 μm) tool is good for milling operation under same material removal rate conditions. It has been also investigated that lower wall thickness (80 μm) tool has less edge chipping area and less taper and can impart high drilling depth as compared to higher wall thickness (100 and 150 μm) tool. It is also concluded that lesser grain size (15 μm) tools are advantageous in terms of edge chipping area and cutting force for drilling and milling operations as compared to higher grain size (30, 35 and 45 μm) tool at constant material removal rate. Higher grain size tools have been broken at 1.13 mm³/h material removal rate conditions due to bad profile accuracy. But higher grain size tools have worked fairly well at less material removal rate condition. Higher grain size tools produced less wear. Tool wear was found minimum in higher wall thickness (100 μm) tool having higher abrasive grain size (30 μm). Using inferred results, Ø0.3 mm drilling experiments have been carried out on six aerospace ceramic materials. Also, groove of 0.5 mm size using Ø0.3 mm optimised tool has been successfully carried out in sintered SiC.     

Use of Phosphate Rock for the Removal of Ni2+ from Aqueous Solutions: Kinetic and Thermodynamics Studies

A study was carried out in batch conditions to examine the removal of nickel ions from an aqueous solution by phosphate rock. The effect of different sorption parameters, such as initial metal concentration, equilibration time, solution pH, and temperature on the amount of Ni2+ sorbed was studied and discussed. The sorption process followed pseudo-second-order kinetics with necessary time of 2?h to reach equilibrium. The maximum removal obtained is at initial pH around 8. Nickel uptake was quantitatively evaluated using the Langmuir and Dubinin–Kaganer–Radushkevich model. The Langmuir adsorption isotherm constant corresponding to adsorption capacity, Q0, was found to be 7.63?mg/g. The possibility of metal recovery was investigated using several eluting agents. The desorbed amount of nickel decreased continuously with increasing pH, and increased with increasing Ca2+ concentration in leaching solution.