Lubricants Health Monitoring

Fault inception and growth in the components of a mechanical power drive are often heavily affected by the lubricant health. As a consequence, monitoring the lubricant health status and signaling a degradation of the lubricant properties could improve the reliability of the mechanical drive. A further merit of implementing a lubricant health monitoring system is the possibility to move from a time-based maintenance to a condition-based maintenance with the ensuing decrease of operating costs and reduction of the environmental impact. This would be of a particular advantage for those applications in which loss of operation generated by poor lubrication could cause a service disruption or lead to a safety critical condition. The proposed paper presents the initial part of an ongoing research activity on lubricants health monitoring. The work so far performed consisted of the following activities: perform a critical review of the studies addressing the lubricants condition; determine which are the significant features of the lubricants used in the majority of mechanical systems, that need to be extracted to assess the lubricant health; which occurences affect the lubricant health and how the oil health status can be assessed by different techniques , whose relative merits will be discussed; define the progression of the degradation of the lubricant health status; present the initial study of how different lubricant health monitoring techniques can be fused together to develop an efficient on-line lubricant health monitoring system. The paper thus presents the summary of the work performed to establish the fundamentals onto which a reliable PHM system for the lubricants of mechanical drives can be developed, that will be the final objective of the on-going research activity

Robust Electromechanical Actuators For Primary Flight Controls

The paper describes an electromechanical actuation system presenting improved reliability, high integrity and prognostic functions able to alert of a developing failure. In this system a flight control surface is driven by two parallel rollerscrews, each driven by a brushless motor with gearhead and clutch; the motors electric drives are controlled by dual redundant electronic units performing closed loop position control as a function of the commands received from the flight control computer. Provisions are taken to provide damping in the event of simultaneous failure of both actuators. The electronic units perform control, diagnosis and prognosis of the actuation system and mutually exchange data via a cross channel data link. The actuation system thereby provides high integrity control of an aerodynamic surface with dual mechanical link, dual power source and quadruplex control, similarly to a fly-by-wire hydraulic flight control. The paper first addresses the critical design issues associated with the electromechanical actuation of flight control surfaces, then outlines configuration, characteristics and performance of the actuation system

Understanding and mitigating resistive losses in fired passivating contacts: role of the interfaces and optimization of the thermal budget

This work presents a study of p-type passivating contacts based on SiCx formed via a rapid thermal processing (RTP) step, using conditions compatible with the firing used to sinter screen-printed metallization pastes in industry. The contributions of the two interfaces (wafer/contact and contact/metal) to the contact resistivity are first decorrelated, identifying tunnelling at the wafer interface as the main contribution. We then investigate the influence of the active dopant concentration on the contact resistivity and the SiCx sheet resistance and propose strategies to reduce both resistances by increasing the thermal budget applied during RTP. Lastly, we discuss potentials and limitations of implementing the investigated stacks as rear side contacts of p-type devices with localized metallization. We demonstrate that increasing the thermal budget during RTP can effectively mitigate resistive losses and enhance contact performance and we show that an oxide layer that can withstand high thermal budgets is the key factor for obtaining simultaneously high passivation quality and good electrical properties. We investigate three different oxide types grown by HNO3 immersion, UV-O3 exposure and N2O plasma oxidation. The latter is demonstrated to be a promising candidate for an application in devices fabricated with high RTP thermal budget.RID/TS/Instrumenten groepRST/Storage of Electrochemical Energ

Growth in Children With Noonan Syndrome and Effects of Growth Hormone Treatment on Adult Height

Objectives: Growth impairment is a common manifestation in Noonan syndrome (NS). Recombinant human GH (rhGH) treatment has been shown to increase growth and adult height (AH) in a few studies. We aimed to evaluate the growth trajectory towards the AH, and the effects of rhGH treatment in a large cohort of NS children. Methods: Retrospective, multicenter, cohort study including subjects with genetic diagnosis of NS. A total of 228 NS patients, 154 with PTPN11 mutations, 94 who reached AH, were recruited. Auxological data were collected at 2, 5, and 10 years, at pubertal onset, at AH. Sixty-eight NS subjects affected with GH deficiency (GHD) were treated with rhGH at a mean dose of 0.24 mg/kg per week until AH achievement. Results: ANOVA analysis showed a significant difference between birth length and height standard deviation scores (HSDS) at the different key ages (p<0.001), while no significant differences were found between HSDS measurements at 2, 5, and 10 years, at pubertal onset, and at AH. HSDS increased from −3.10 ± 0.84 to −2.31 ± 0.99 during rhGH treatment, with a total height gain of 0.79 ± 0.74, and no significant difference between untreated and treated NS at AH. Conclusions: rhGH treatment at the standard dose used for children with GH idiopathic deficiency is effective in improving growth and AH in NS with GHD. Further studies are needed to assess genotype-specific response to rhGH treatment in the different pathogenic variants of PTPN11 gene and in the less common genotypes

Growth in Children With Noonan Syndrome and Effects of Growth Hormone Treatment on Adult Height

Objectives: Growth impairment is a common manifestation in Noonan syndrome (NS). Recombinant human GH (rhGH) treatment has been shown to increase growth and adult height (AH) in a few studies. We aimed to evaluate the growth trajectory towards the AH, and the effects of rhGH treatment in a large cohort of NS children. Methods: Retrospective, multicenter, cohort study including subjects with genetic diagnosis of NS. A total of 228 NS patients, 154 with PTPN11 mutations, 94 who reached AH, were recruited. Auxological data were collected at 2, 5, and 10 years, at pubertal onset, at AH. Sixty-eight NS subjects affected with GH deficiency (GHD) were treated with rhGH at a mean dose of 0.24 mg/kg per week until AH achievement. Results: ANOVA analysis showed a significant difference between birth length and height standard deviation scores (HSDS) at the different key ages (p<0.001), while no significant differences were found between HSDS measurements at 2, 5, and 10 years, at pubertal onset, and at AH. HSDS increased from 123.10 \ub1 0.84 to 122.31 \ub1 0.99 during rhGH treatment, with a total height gain of 0.79 \ub1 0.74, and no significant difference between untreated and treated NS at AH. Conclusions: rhGH treatment at the standard dose used for children with GH idiopathic deficiency is effective in improving growth and AH in NS with GHD. Further studies are needed to assess genotype-specific response to rhGH treatment in the different pathogenic variants of PTPN11 gene and in the less common genotypes