PWR AND WWER STEAM GENERATOR TUBE INTEGRITY ASSESSMENT

ABSTRACT Paper is describing and comparing degradation mechanisms and integrity assessment of PWR and WWER type of steam generator tubes. Because of different design, different used materials and also different operating conditions, there are significant differences in degradation mechanisms. Therefore both steam generator types have their specific codes dealing with inspection, monitoring and maintenance

Auswirkungen der 12. Novelle des Arzneimittelgesetzes auf das Prüfverfahren einer Ethik-Kommission: ein Erfahrungsbericht aus der Ethik-Kommission der Medizinischen Fakultät der Universität Rostock

Der Rechtsstatus der deutschen Ethik-Kommissionen hat durch das Inkrafttreten der 12. Novelle des Arzneimittelgesetzes (AMG) im August 2004 und dem Erlass der Good Clinical Practise-Verordnung (GCP-V) eine Neudefinition mit erheblichen Konsequenzen für die Arbeit der Ethik-Kommissionen und die Antragstellung von klinischen Studien mit Arzneimitteln erhalten. Um die Auswirkungen auf die Arbeit der Ethik-Kommission Rostock und die Antragstellung aufzuzeigen, wurden eingereichte Anträge zu Arzneimittelstudien vor und nach 12. AMG-Novelle miteinander verglichen

Long-term decoding of movement force and direction with a wireless myoelectric implant

Objective. The ease of use and number of degrees of freedom of current myoelectric hand prostheses is limited by the information content and reliability of the surface electromyography (sEMG) signals used to control them. For example, cross-talk limits the capacity to pick up signals from small or deep muscles, such as the forearm muscles for distal arm amputations, or sites of targeted muscle reinnervation (TMR) for proximal amputations. Here we test if signals recorded from the fully implanted, induction-powered wireless Myoplant system allow long-term decoding of continuous as well as discrete movement parameters with better reliability than equivalent sEMG recordings. The Myoplant system uses a centralized implant to transmit broadband EMG activity from four distributed bipolar epimysial electrodes. Approach. Two Rhesus macaques received implants in their backs, while electrodes were placed in their upper arm. One of the monkeys was trained to do a cursor task via a haptic robot, allowing us to control the forces exerted by the animal during arm movements. The second animal was trained to perform a center-out reaching task on a touchscreen. We compared the implanted system with concurrent sEMG recordings by evaluating our ability to decode time-varying force in one animal and discrete reach directions in the other from multiple features extracted from the raw EMG signals. Main results. In both cases, data from the implant allowed a decoder trained with data from a single day to maintain an accurate decoding performance during the following months, which was not the case for concurrent surface EMG recordings conducted simultaneously over the same muscles. Significance. These results show that a fully implantable, centralized wireless EMG system is particularly suited for long-term stable decoding of dynamic movements in demanding applications such as advanced forelimb prosthetics in a wide range of configurations (distal amputations, TMR).German Federal Ministry for Education and Reseach (BMBF) grant No, 16SV3695, 16SV3699, 16SV3697 and 01GQ1005C, DFG Deutsche Forschungsgemeinschaft grant No. GA1475-C

Snížení tepelného namáhání kolektorů parogenerátoru v oblasti svarového spoje pomocí externího chlazení

Presented paper deals with possibility of external cooling of steam generator welds area to decrease internal tensile thermal stresses which are one of the causes of cracking in this area. On various WWER-440 nuclear power plants (NPP) steam generators (SG) occurred quite serious problem of cracking in weld joints connecting primary collectors to the SG vessels nozzle. The cause of this cracking is stress corrosion cracking (SCC) mechanism. Results of these analyses showed that by proper external cooling of the weld area it is possible not just to decrease significantly existing tensile stresses, but to change them into compressive ones. This of course would have great impact on crack occurrence and growth.Uvedený článek se zabývá možností vnějšího chlazení kolektoru parního generátoru v oblasti svaru, za účelem snížení tahového napětí od teploty, které jsou jednou z příčin vzniku trhlin v této oblasti. Na různých jaderných elektrárnách typu VVER-440 se vyskytly poměrně závažné vady spojené se vznikem trhlin ve svarovém spoji spojujícím primární kolektory s nátrubky parního generátoru. Příčinou těchto trhlin je mechanizmus korozního praskání pod napětím (SCC). Výsledky těchto analýz ukazují, že vhodným vnějším chlazením svaru je možné nejen výrazně snížit existující tahové napětí, ale dokonce je změnit v tlakové. To samozřejmě bude mít velký vliv na vznik trhlin a jejich další šíření

Design of a rail-to-rail folded cascode amplifier with transconductance feedback circuit

In this work a programmable folded cascode railto-rail operational amplifier (OpAmp) with small settling time and transconductance feedback circuit is proposed. It employs a 130 nm CMOS technology with 1.2 V power supply. The small settling time is required to charge an ADC within a given time frame. The OpAmp achieves a gain bandwidth of 19.95 MHz with a 70 pF load and a minimum settling time of 144 ns while consuming 0.551 mA quiescent current. It can be shown that with 130 nm technology, high performance amplifiers can be realized on very small area