ECOLE

ECOLE is a Comenius 3 Network under the SOCRATES programme in the field of education running from 2002-2004. The main goal of Comenius Networks is to create links between projects carried out by school partnerships and those relating to the training of school education staff. This paper presents the outcome of the first year of the project with a special emphasis on the information and communication (ICT) infrastructure and the events. Project description covers an interactive website comprising information related to the activities of the network and an advisory reference point on running projects, database with projects, best practices, online teacher training, open working areas, project space, communication tools and so on.

Testing of a torque sensor used to measure the parameters of the briquetting process of lignocellulosic materials

The study presents a control and measurement system for the drive parameters of screw compactor machine with open working chamber for shredded materials. The study demonstrates the construction and working principle of the torque sensor for measuring the torque of the motor driving the compacting screw. The calibration method for the measuring system was presented together with example measurement results for compaction of broken up rye straw, oat straw and hay. The study results were analyzed for feasibility of use for the compaction of materials with specific thermomechanical properties. The conclusion presents the possible forms of application of the established solution in mass production.

Functional and construction indicator for the briquetting process of lignocellulosic materials

The study presents the possibility to measure the torque and axial force of the working system of the screw compactor machine with open working chamber. Attention was drawn to the relationship between the two parameters and the geometric properties of the working system and the thermomechanical properties of the compacted materials. A functional construction coefficient was proposed and defined to bound together the value of torque and axial force. Its usability was demonstrated for identifying the parameters of compaction process together with its applicability for controlling these types of processes.

Testing of a force sensor used to measure the briquetting process parameters of lignocellulosic materials

The study presents a control and measurement system for the drive parameters of screw compactor machine with open working chamber for shredded materials. The study demonstrates the construction and working principle of the force sensor for measuring the axial force at the compacting screw. The calibration method for the measuring system was presented together with example measurement results for compaction of broken up rye straw, oat straw and hay. The study results were analyzed for feasibility of use for the compaction of materials with specific thermomechanical properties. The conclusion presents the possible forms of application of the established solution in mass production.

Braking characteristics integrating open working chamber model and hydraulic control system model in a hydrodynamic retarder

Hydraulic control system has important influence on the steady and transient braking performance of a hydrodynamic retarder. The braking characteristics of hydrodynamic retarder regulated by hydraulic control system should be investigated first, before designing and making the braking strategy and control method. The accurate and detailed braking characteristics models of open working chamber and hydraulic control system are established, integrated, and validated by steady and dynamic experimental data. Based on full factorial design experimental method, the influence of control parameters on braking performance achieving steady state is analyzed with parameter sensitivity, and the effect of control parameters on braking response characteristics is conducted. Then the influence of different tube lengths between working chamber and hydraulic control system on braking performance is discussed and analyzed. The results show the control pressure and rotor rotational speed both have significant impact on braking characteristics with obvious nonlinear, coupling, and interaction effect. The longer response time of hydraulic control system will be for the larger braking torque. Shortening the tube lengths as much as possible is needed to improve the braking torque, cooling flow rate, and system integration.

Study on influence of inlet and outlet flow rates on oil pressures and braking torque in a hydrodynamic retarder

Purpose Traditional prediction of braking characteristics of vehicular hydrodynamic retarders is commonly conducted based on braking characteristics model of closed working chamber, namely, closed working chamber model (CWCM). In CWCM, inlet and outlet oil pressures and braking torque are considered to be independent of inlet and outlet flow rates. However, inlet and outlet flow rates can affect internal and external braking characteristics under actual working conditions. This study aims to establish a more accurate braking characteristics model of a hydrodynamic retarder under full oil-charging condition, and then the influence of varying inlet and outlet flow rates on oil pressures and braking torque is investigated in this paper. Design/methodology/approach A full flow passage of working chamber in a hydrodynamic retarder with inlet and outlets was established, and the reliability of numerical model was analyzed and validated. Pressure rise was introduced to describe the variation of inlet and outlet oil pressures. Then, on the basis of the validation, the CWCM was proposed at different rotor rotational speeds. The inlet and outlet oil pressures and braking torque were numerically computed at different inlet and outlet flow rates with Full Factorial Design experimental method. The results obtained were involved into establishing the braking characteristics model of open working chamber, namely, open working chamber model (OWCM), combined with Radial basis function approximation model. The OWCM with different inlet and outlet flow rates was analyzed and compared with CWCM. Findings The results show that inlet and outlet flow rates have obvious influence on the variation of inlet and outlet oil pressures in OWCM compared with CWCM. The outlet A pressure rise significantly changes with the inlet and outlet A flow rates, while the pressure rise of outlet B is mainly affected by the outlet B flow rate. Originality/value This paper presents an OWCM of hydrodynamic retarders under full oil-charging condition. The model takes into account the impact of oil inflowing and outflowing from the working chamber, which can provide a more accurate prediction of braking characteristics of hydrodynamic retarders.

STUDI ANALISA KOORDINASI RELAI GFR INCOMING BUSBAR 20 KV DAN GFR SALURAN UNTUK MENGAMANKAN GANGGUAN SATU PHASA KETANAH DI TRANSFORMATOR 3 GARDU INDUK KAPAL

Disruption of the distribution system is generally caused by a short circuit that causes overcurrent, one single phase short circuit to ground. Single phase to ground disturbances that occurred at the feeder should be secured by a ground fault relays in feeders. However, due to an error of coordination, interference with the feeder perceived also to the incoming side of the transformer so that ground fault relays on the incoming 20 kV ordered PMT 20 kV at the transformer side open. Working time ground fault relays in feeders Peguyangan is for 0.25 seconds. While working time ground fault relays in the incoming 20 kV is for 0.5 seconds. This indicates that differences in work time relay by 0.25 seconds is considered selective. The event of disruption of the ground phase, GFR relay coordination in securing the area of ??interference must be gradual. Where the value of working time ground fault relays in the base should be longer than the time ground fault relays working on a feeder. It aims to work ground fault relays working order, so that errors can be avoided in the security and do not lead to the spread of disturbed areas.