A numerical study on active control for tiltrotor whirl flutter stability augmentation

The use of active control to augment whirl flutter stability of tiltrotor aircraft is studied by means of a multibody simulation. The numerical model is based on a 1/5 scale semi-span aeroelastic wind tunnel model of a generic tiltrotor concept and possesses a gimballed, stiff-in-plane rotor that is windmilling. A single-input single-output controller and two types of multi-input multi-output algorithms, Linear Quadratic Gaussian Control and Generalized Predictive Control, are studied. They are using measured wing deflections in order to calculate appropriate swashplate input. Results on the closed-loop behavior of three wing and two gimbal natural modes are given. Robustness analyses with respect to major parameters like wing natural frequencies or structural damping are also briefly discussed. The rotor shear force is shown in the uncontrolled condition and in presence of a controller in order to illustrate the whirl flutter mechanism. The single-input single-output controller yielded substantial gain in stability and turned out to be most suitable for industrial application, whereas the Linear Quadratic Gaussian Regulator yielded even higher damping and still had good robustness characteristics

Evaluation of Direct and Indirect Methods of Repairing Fractured

INTRODUCTION: The most common technology used in producing a fixed partial denture is firing porcelain to metal. The fracture of veneering material rarely occurs, although it is one of the most striking problems in daily practise. PURPOSE: The purpose of this study was to evaluate the shear bond strength of composite to porcelain and metal by using two intraoral repair methods: direct and indirect. MATERIAL AND METHODS: The direct method was performed by using Ceramic Repair System (Ivoclar, Lichtenstein) with and without sandblasting. The indirect method involved Co-Jet system (ESPE,Germany) and Rely X ARC (3M,USA) as luting agents. 180 specimens fabricated with feldspathic porcelain and Ni-Cr alloy were divided into 3 groups: CR/0 (direct method of repair without sandblasting), CR/S (direct method of repair with sandblasting) and CJ (indirect method based on Co-Jet system). Each of them was divided into 3 subgroups of 20: porcelain (P), porcelain and metal (P/M) and metal (M). The 10 specimens were then subjected to a shear test in a mechanical testing machine at a crosshead speed of 0.5 mm/min. Mode of failure was recorded. Means and standart deviations of loads were calculated. RESULTS: Tested groups exhibited the following values in megapascals: CR/0-P = 20.36 ± 3.05; CR/0-P/M = 19.45 ± 3.49; CR/0-M = 10.86 ± 4.1; CR/S-P = 18.21 ± 2.62; CR/S-P/M = 19.34 ± 1.76; CR/S-M = 9,54 ± 2.48; CJ-P = 19.85 ± 1.94; CJ-P/M = 19,78 ± 3.60; CJ-M = 13.56 ± 3.82. The mean fractured loads were significantly lower for metal subgroups than for porcelain and porcelain/ metal subgroups. CONCLUSION: Higher shear bond strength is expected when porcelain was fractured without extensive metal exposure

Evaluation of Direct and Indirect Methods of Repairing Fractured

INTRODUCTION: The most common technology used in producing a fixed partial denture is firing porcelain to metal. The fracture of veneering material rarely occurs, although it is one of the most striking problems in daily practise. PURPOSE: The purpose of this study was to evaluate the shear bond strength of composite to porcelain and metal by using two intraoral repair methods: direct and indirect. MATERIAL AND METHODS: The direct method was performed by using Ceramic Repair System (Ivoclar, Lichtenstein) with and without sandblasting. The indirect method involved Co-Jet system (ESPE,Germany) and Rely X ARC (3M,USA) as luting agents. 180 specimens fabricated with feldspathic porcelain and Ni-Cr alloy were divided into 3 groups: CR/0 (direct method of repair without sandblasting), CR/S (direct method of repair with sandblasting) and CJ (indirect method based on Co-Jet system). Each of them was divided into 3 subgroups of 20: porcelain (P), porcelain and metal (P/M) and metal (M). The 10 specimens were then subjected to a shear test in a mechanical testing machine at a crosshead speed of 0.5 mm/min. Mode of failure was recorded. Means and standart deviations of loads were calculated. RESULTS: Tested groups exhibited the following values in megapascals: CR/0-P = 20.36 ± 3.05; CR/0-P/M = 19.45 ± 3.49; CR/0-M = 10.86 ± 4.1; CR/S-P = 18.21 ± 2.62; CR/S-P/M = 19.34 ± 1.76; CR/S-M = 9,54 ± 2.48; CJ-P = 19.85 ± 1.94; CJ-P/M = 19,78 ± 3.60; CJ-M = 13.56 ± 3.82. The mean fractured loads were significantly lower for metal subgroups than for porcelain and porcelain/ metal subgroups. CONCLUSION: Higher shear bond strength is expected when porcelain was fractured without extensive metal exposure

A multicenter prospective randomized controlled trial investigating the effects of combustion-free nicotine alternatives on cardiovascular risk factors and metabolic parameters in individuals with type 2 diabetes who smoke: the DiaSmokeFree study protocol

Stopping smoking is crucial for public health and especially for individuals with diabetes. Combustion-free nicotine alternatives like e-cigarettes and heated tobacco products are increasingly being used as substitutes for conventional cigarettes, contributing to the decline in smoking prevalence. However, there is limited information about the long-term health impact of those products in patients with diabetes. This randomized controlled trial aims to investigate whether switching from conventional cigarettes to combustion-free nicotine alternatives will lead to a measurable improvement in cardiovascular risk factors and metabolic parameters over a period of 2 years in smokers with type 2 diabetes. The multicenter study will be conducted in seven sites across four countries. A total of 576 smokers with type 2 diabetes will be randomly assigned (1:2 ratio) to either standard of care with brief cessation advice (Control Arm) or combustion-free nicotine alternatives use (Intervention Arm). The primary end point is the change in the proportion of patients with metabolic syndrome between baseline and the 2-year follow-up. Additionally, the study will analyze the absolute change in the sum of the individual factors of metabolic syndrome at each study time point. Patient recruitment has started in September 2021 and enrollment is expected to be completed by December 2023. Results will be reported in 2026. This study may provide valuable insights into cardiovascular and metabolic health benefits or risks associated with using combustion-free nicotine alternatives for individuals with type 2 diabetes who are seeking alternatives to tobacco cigarette smoking. The study protocol, informed consent forms, and relevant documents were approved by seven ethical review boards. Study results will be disseminated through articles published in high-quality, peer-reviewed journals and presentations at conferences

A multibody study on single- and multi-variable control algorithms for tiltrotor whirl flutter stability augmentation

The results of a numerical study on prop-rotor whirl flutter stability augmentation are presented in this paper. Based on a 1/5 scale semi-span aeroelastic wind tunnel model of a generic tiltrotor concept, a numerical simulation is set up using a general purpose multibody simulation tool. The model possesses a gimballed stiff-in-plane rotor with a constant velocity drive system. Three different control algorithms are presented and evaluated. Firstly, there is a single-input single-output controller using conditioned wing deflection feedback on longitudinal cyclic swashplate input. Secondly, two types of multi-input multi-output control that are based on time domain identification of the model are presented: A Linear Quadratic Regulator with a Kalman-Bucy state estimator and a Generalized Predictive Control algorithm. Both of them use measured wing deflections in order to calculate appropriate swashplate input. The control studies are done with a windmilling rotor. Detailed results of the closed-loop behavior of three wing and two gimbal natural modes are presented up to the closed-loop stability boundaries. Robustness analyses of the algorithms with respect to wing natural frequencies, structural damping, flight speed, rotation speed, flight altitude and signal noise are an integral part of the article. The rotor shear force is shown in the open-loop condition and in presence of a controller in order to illustrate the whirl flutter mechanism and the action of the controller. The three control methods yielded substantial gain in stability and critical speed and they showed good robustness margins

Awareness of the implementation of the Falsified Medicines Directive among pharmaceutical companies’ professionals in the European Economic Area

Background: The Falsified Medicines Directive (FMD) is a response of the European Union to the increasing number of falsified medicines present in the legal supply chain within the Member States of the community. Effective implementation of the new regulations will depend on the effective cooperation of all parties involved in the distribution of medicinal products including the managers of pharmaceutical companies. Objective: The objective of the study was to examine awareness of the Implementation of the FMD among pharmaceutical company professionals in the European Economic Area. Methods: Sampling was conducted using a method called purposive sampling. An appropriate research tool in the form of an original questionnaire was made available to the respondents in electronic form. During the period from January 2016 to June 2016, 1,496 e-mail messages were sent. The response rate was 17.37%. Results: The study included 99 women (39.3%) and 153 men (60.7%). In the study group, 95.7% of people had heard of FMD. Doctors had rarely heard about the falsified medicine directive when compared to pharmacists (p=0.0063), people working in the pharmaceutical industry (p=0.0014), and respondents with a different professional profile (p=0.0114). In the study group, 89.6% of people were aware of the role of National Medicines Verification Organization in the process of implementing the provisions of FMD into the national system of distribution of medicinal products. The number of the respondents who knew the deadline for the implementation of FMD was significantly higher in the study population, i.e. 91.9% (p=0.0001). Both the younger respondents and those with lower level of education were less aware of the time requirements posed to national regulators (p=0.0003, p=0.0023, respectively). Conclusions: Awareness of the regulations related to the implementation of the FMD, although relatively high among pharmaceutical company professionals in the EEA, is still insufficient