Soil-borne microorganisms and soil-type affect pyrrolizidine alkaloids in Jacobaea vulgaris

Secondary metabolites like pyrrolizidine alkaloids (PAs) play a crucial part in plant defense. We studied the effects of soil-borne microorganisms and soil-type on pyrrolizidine alkaloids in roots and shoots of Jacobaea vulgaris. We used clones of two genotypes from a dune area (Meijendel), propagated by tissue culture and grown on two sterilized soils and sterilized soils inoculated with 5% of non-sterilized soil of either of the two soil-types. Soil-borne microorganisms and soil-type affected the composition of PAs. By changing the composition rather than the total concentration below and aboveground, plants have a more complex defense strategy than formerly thought. Interestingly, a stronger negative effect on plant growth was found in sterilized soils inoculated with their ‘own’ microbial community suggesting that pathogenic and/or other plant inhibiting microorganisms were adapted to their ‘own’ soil conditions

Evaluation of a sliding mode fault-tolerant controller for the El Al incident

This paper presents piloted flight simulator results associated with the El Al flight 1862 scenario, using a modelreferencebased sliding mode control allocation scheme for fault-tolerant control. The proposed controller design was carried out without any knowledge of the type of failure and in the absence of any fault detection and isolation strategy. This is motivated by the fact that the flight crew were unaware of the losses of the right engines. For this reason, the control allocation scheme proposed uses (fixed) equal distribution of the control signals to all actuators (for both nominal situations and when a fault or failure occurs). This paper analyzes the scheme and determines the conditions under which closed-loop stability is retained. The results represent the successful realtime implementation of the proposed controller on a flight simulator, configured to represent a B747 aircraft. The evaluation results from the experienced pilots show that the proposed controller has the ability to position the aircraft for landing, both in a nominal scenario and in the El Al failure scenario. It is also shown that actuator faults and failures that occurred during the El Al incident can be handled directly without reconfiguring the controller

Fault tolerant sliding mode control design with piloted simulator evaluation

Copyright © 2008 American Institute of Aeronautics and AstronauticsThis paper considers sliding mode allocation schemes for fault tolerant control. The schemes allow redistribution of the control signals to the remaining functioning actuators when a fault or failure occurs. The paper analyzes the schemes and determines conditions under which closed–loop stability is retained for a certain class of faults and failures. It is shown that faults and even certain total actuator failures can be handled directly without reconfiguring the controller. The results obtained from implementing the controllers on the SIMONA research flight simulator, configured to represent a B747 aircraft, show good performance in both nominal and failure scenarios even in wind and gust conditions

Sliding Mode Propulsion Control Tests on a Motion Flight Simulator

This paper describes a fault-tolerant sliding-mode control allocation scheme capable of coping with the loss of all control surfaces resulting from a failure of the hydraulics system, during which time the scheme only uses the engines to control the aircraft. The paper presents tests of the scheme implemented on a six-degree-of-freedom motion research flight simulator at Delft University of Technology, using a realistic maneuver involving an emergency return to a near-landing condition on a runway in response to the failure. The simulator results show that not only does the controller provide high tracking performance during nominal fault-free conditions, this performance is also maintained after the total loss of all control surfaces. This shows the capability of the proposed sliding-mode control allocation scheme to achieve and maintain desired performance levels using only propulsion by redistributing the control signals to the engines when failures occur

Real-time implementation of an ISM Fault Tolerant Control scheme for LPV plants

Copyright © 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This paper proposes a fault tolerant control scheme for linear parameter varying systems based on integral sliding modes and control allocation, and describes the implementation and evaluation of the controllers on a 6 degree-of-freedom research flight simulator called SIMONA. The fault tolerant control scheme is developed using a linear parameter varying approach to extend ideas previously developed for linear time invariant systems, in order to cover a wide range of operating conditions. The scheme benefits from the combination of the inherent robustness properties of integral sliding modes (to ensure sliding occurs throughout the simulation) and control allocation, which has the ability to redistribute control signals to all available actuators in the event of faults/failures

Inflammatory mediators in children with protein-energy malnutrition1-3

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