Search results for "system p"
showing 10 items of 222 documents
The modulation of immune complex aggregation by classical pathway-mediated reactions.
1985
Abstract Classical pathway (CP)-triggered reactions of complement-modulated immune complex(IC) aggregation (tetanus toxoid/human anti-tetanus toxoid-IgG; ICs of equivalence) were investigated turbidimetrically during the early stages of reaction. Monospecific Fab'- or Fab-fragments (rabbit) directed against certain complement components were used to block the complement function in normal human serum (NHS). Additionally, parts of the reactions were studied using purified complement components. C1q in serum generated by the addition of EDTA as well as purified C1q were found to increase the IC aggregation. In contrast to C1q, macromolecular C1 is able to inhibit IC aggregation, whereas addit…
ESR Spectra o f Normal Human Serum after Treatment with Complement Activating Agents*
1980
Abstract We describe the appearance of a free-radical signal in the ESR spectrum of normal human serum incubated with several complement activating agents. The intensity of this signal is dependent of dose of activating agents, time and temperature. Signals elicited by different complement activators differ in morphology and kinetics. Inhibition by treatment with EDTA and the presence of the signal in activated C 6-deficient rabbit serum suggest that the con-vertase forming steps of complement activation (C2 to 5) could be the source of free-radical containing molecules.
The public procurement of information systems: dialectics in requirements specification
2017
When acquiring information systems, public entities face a dilemma. On the one hand, they want to procure the system that best suits their needs, which often requires lengthy dialogues with vendors. At the same time, they are restricted by government regulations that mandate limited dialogue in the interests of transparency and equal opportunities for all vendors. To examine how public entities deal with this, we followed three procurement projects in Norway. We show that this dilemma manifests itself as a dialectic between the thesis of getting the system requirements right and the antithesis of strictly adhering to regulations. Public entities search for a resolution of this dialectic thr…
Applications of the Fault Decoupling Device to Improve the Operation of LV Distribution Networks
2008
The aim of this paper is to present the operating principle of a new resonant device, called the fault decoupling device (FDD), able to improve power quality in electrical distribution systems. In low-voltage networks, this device can be employed in order to mitigate voltage dips due to faults or large induction motor startup. Moreover, in the presence of distributed-generation (DG) units, the FDD allows one to obtain various benefits such as a reduction of the fault current in each node of the network and an increase in the voltage at the DG unit node. In order to show the performances of the FDD, analytical studies and computer simulations were carried out which took into account various …
A Method to Evaluate Voltages to Earth During an Earth Fault in an HV Network in a System of Interconnected Earth Electrodes of MV/LV Substations
2008
An easy and swift method to evaluate, in a system of interconnected earth electrodes, earth potentials on earthing systems of medium-voltage/low-voltage (MV/LV) substations, in an event of single-line-to-earth fault inside a high-voltage/medium- voltage (HV/MV) station, is presented. The advantage of the method is the simplicity of the mathematical model for solving complex systems of any size with a sufficient accuracy for practical purposes. This paper shows the results of simulations, performed on networks with different extensions and characteristics, organized in easy-to-read graphs and tables. A comparison of these results with the values obtained according to the procedure explained …
Investigating the effect of distributed generators on traditional protection in radial distribution systems
2013
The recent changes in power network structure, development in green energy technologies and increased attention on environmental concerns have led to increase the installation of renewable energy based distributed generations (DG) in distribution networks. The increasing penetration of distributed generation in the distribution power system creates new technical and economical challenges; protection is one important topic of these challenges. High penetration of DG will have unfavorable impact on the traditional protection methods; the impact depends on the number, location and size of injected DG. To ensure safe and selective protection devices coordination, the impact of DG should be take…
Photovoltaic plant array reconfiguration: Design of a new device
2014
An efficient strategy to improve unequally irradiated PV plants performances is based on the reconfiguration of the connections between the modules. In this paper, an algorithm, for this purpose conceived, is presented. Moreover, the design, realization and finally also the set up of a new reconfiguration system device is fully shown and discussed. The algorithm conceived simulates several possible series-parallel connections under varying irradiation conditions, and determines the optimal modules connection in order to get the maximum output power. In this way, the reconfiguration system may set up the reconfiguration strategy. The reconfiguration system prototype set up, basically consist…
UPS fuel cell based: An innovative back-up system
2007
The aim of the paper is to evaluate the technical feasibility and aspects related to the use, in an Uninterruptible Power Supply (UPS), of fuel cells instead of traditional electrochemical batteries. The proposed system, named UPS-FCB (Fuel Cell Based) presents a modular and versatile system configuration; particularly it is possible to integrate it with traditional UPS. Moreover the system features can be modified in terms of power, reliability, back-up time, etc., by changing the power devices. A detailed experimental analysis has been carried out on a passive stand-by UPS integrated with a FCB; experimental results can be easily extended to the other possible system architectures. © 2007…
Decoding the Japanese Lean Production System according to a Viable Systems Perspective
2012
The increase in the complexity and variability of the business environment, due to constant and rapid changes in markets, calls for more flexible and effective production systems. Of the most valuable production systems, the Japanese lean production system (LPS) is the best known and studied, but is still not the most widely applied with success outside Japan. The reason for the low level of success of lean production outside its native country is the lack of understanding of the strong interactions which hold between enterprises and business systems. In order to fill this gap in our knowledge, we investigate the systemic interactions according to the Viable System View. To develop our anal…
Control of solid-state fault current limiter for DG-integrated distribution systems
2017
Fault current limier (FCL) is a device that limits the system current under fault conditions without disconnecting the system and affecting the power system protection components such as circuit breakers. Many types of FCLs have been proposed to limit the magnitude of the fault current. Solid-state fault current limiters (SSFCLs) can limit the peak value of the fault current by applying several methods, such as controlling the system impedance or controlling the voltage that appears across the fault. In this paper, a new control scheme for the SSFCL circuit is presented. The control method is based on controlling the duty cycle of solid state switches to control the rms value of the system …