Search results for "DRIVE"
showing 10 items of 543 documents
Tuning active Brownian motion with shot noise energy pulses
2009
The main aim of this work is to explore the possibility of modeling the biological energy support mediated by absorption of ATP (adenosine triphosphate) as an energetic shot noise. We develop a general model with discrete input of energy pulses and study shot-noise-driven ratchets. We consider these ratchets as prototypes of Brownian motors driven by energy-rich ATP molecules. Our model is a stochastic machine able to acquire energy from the environment and convert it into kinetic energy of motion. We present characteristic features and demonstrate the possibility of tuning these motors by adapting the mean frequency of the discrete energy inputs, which are described as a special shot noise…
Improving the speed estimation by load torque estimation in induction motor drives: an MRAS and NUIO approach
2021
This paper proposes the application of the NUIO inside a FOC induction motor drive for the simultaneous estimation of the load torque and the rotor speed. The idea is to estimate at first the speed with the current model in parallel with a reference model developed on the basis of the voltage model of the induction machine. Then, the estimated speed is given as input to a nonlinear unknown input observer (NUIO) to estimate the load torque. This estimation is then used to correct the previous estimation of the speed. Simulation and experimental results confirm the goodness of the method for an extended range of speed and different load torque, and they confirm the reduction of error in trans…
Vulnerability matrix of the food system : operationalizing vulnerability and addressing food security
2016
Food security is the major desired outcome of any food system, but its realization may be prevented by vulnerabilities in a food system. By shifting the focus of their vulnerability analysis from the discrete components of the food system to the food system as a whole, the authors of this article were able to develop a qualitative food system vulnerability matrix. The objective of the research was to make the concept of food system vulnerability operational by identifying vulnerability drivers, vulnerable systems and vulnerable subclasses in light of food security. The vulnerability matrix was set up with five classes of vulnerable systems (‘Vulnerability of what?’) on the horizontal axis a…
Light-driven proton transport of bacteriorhodopsin incorporated into long-term stable liposomes of a polymerizable sulfolipid
1983
Abstract The chromoprotein bacteriorhodopsin from Halobacterium halobium has been incorporated into liposomes made of a fully synthetic, polymerizable lipid. Bacteriorhodopsin is found to be active in these polymer liposomes. The advantage in the use of such polymer systems concerning long-term stability in comparison with liposomes made of natural lipid is demonstrated.
Magnetohydrodynamic study on the effect of the gravity stratification on flux rope ejections
2013
Context. Coronal mass ejections (CMEs) are the most violent phenomenon found on the Sun. One model that explains their occurrence is the flux rope ejection model. A magnetic flux rope is ejected from the solar corona and reaches the interplanetary space where it interacts with the pre-existing magnetic fields and plasma. Both gravity and the stratification of the corona affect the early evolution of the flux rope. Aims. Our aim is to study the role of gravitational stratification on the propagation of CMEs. In particular, we assess how it influences the speed and shape of CMEs and under what conditions the flux rope ejection becomes a CME or when it is quenched. Methods. We ran a set of MHD…
A fast multi-dimensional magnetohydrodynamic formulation of the transition region adaptive conduction (TRAC) method
2021
We have demonstrated that the Transition Region Adaptive Conduction (TRAC) method permits fast and accurate numerical solutions of the field-aligned hydrodynamic equations, successfully removing the influence of numerical resolution on the coronal density response to impulsive heating. This is achieved by adjusting the parallel thermal conductivity, radiative loss, and heating rates to broaden the transition region (TR), below a global cutoff temperature, so that the steep gradients are spatially resolved even when using coarse numerical grids. Implementing the original 1D formulation of TRAC in multi-dimensional magnetohydrodynamic (MHD) models would require tracing a large number of magne…
Examining the Impact of ICT on Sustainable Development: A Data-Driven Narrative
2021
Considering the challenges of sustainable development and the mixed prescriptions being offered by the use of digital technologies, we present a data-driven narrative of how ICT development impacts the sustainable growth of economies. The analysis is based on historical panel data from 39 economies across the developed and developing economies. The industry-standard CRISP-DM methodology was applied as it is flexible, robust, and offers a practical approach for data analytics. The findings reveal that there are differentiated outcomes in terms of sustainable growth among high-income and low-income economies. This poses legitimate questions as to whether low-income economies will be able to m…
Designing of microcontroller based Syringe Pump with variable and low delivery rates for the administration of small volumes
2015
Delivering medications and fluids intravenously is a common practice in modern medical procedures. Administering medications or fluids directly into a patient's blood circulation results in a predictable and immediate absorption of the drug or fluid administered, this may play a vital role in the treatment of certain acute conditions which require immediate action by drugs or fluids. Syringe Pumps are highly useful in delivering a precise quantity of the substance at specific periods of time as required. This research presents a proposal to create a cost effective working prototype of syringe pump for variable and low delivery rates for the administration of small volumes. The presented Syr…
Assessing the Effect of Drivers’ Gender on Their Intention to Use Fully Automated Vehicles
2021
Although fully automated vehicles (SAE level 5) are expected to acquire a major relevance for transportation dynamics by the next few years, the number of studies addressing their perceived benefits from the perspective of human factors remains substantially limited. This study aimed, firstly, to assess the relationships among drivers’ demographic factors, their assessment of five key features of automated vehicles (i.e., increased connectivity, reduced driving demands, fuel and trip-related efficiency, and safety improvements), and their intention to use them, and secondly, to test the predictive role of the feature’ valuations over usage intention, focusing on gender as a key …
Experimental Implementation of an Enhanced Field Oriented Control Strategy for Induction Motors Using a Low-Cost ATSAM3X8E Microcontroller
2020
This paper presents a low-cost Micro Controller Unit (MCU) implementation of an enhanced Field Oriented Control (FOC) technique that takes into account the non-linearity of the ferromagnetic material. The algorithm is applied to a three-phase 5.5 kW Induction Motor (IM) and experimentally carried out by means of an ATMEL ATSAM3X8E microcontroller. The effectiveness of the enhanced control strategy is verified by comparing the dynamic performances of the electric drive with those obtained by means of a traditional FOC technique. For this purpose, an experimental test bench is set up for the implementation of the enhanced FOC technique. Finally, the technical and economic features of the simp…