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Krzysztof Badyda, Wojciech Bujalski, Grzegorz Niewiński and Michał Warchoł

Selected issues related to heat storage tank modelling and optimisation aimed at forecasting its operation

The paper presents results of research focused on modelling heat storage tank operation used for forecasting purposes. It presents selected issues related to mathematical modelling of heat storage tanks and related equipment and discusses solution process of the optimisation task. Presented detailed results were obtained during real-life industrial implementation of the optimisation process at the Siekierki combined heat and power (CHP) plant in Warsaw owned by Vattenfall Heat Poland S.A. (currently by Polish Oil & Gas Company - PGNiG SA) carried out by the Academic Research Centre of Power Industry and Environment Protection, Warsaw University of Technology in collaboration with Transition Technologies S.A. company.

Open access

Marcin Grodzki, Piotr Darnowski and Grzegorz Niewiński


The paper presents a neutronic analysis of the battery-type 20 MWth high-temperature gas cooled reactor. The developed reactor model is based on the publicly available data being an ‘early design’ variant of the U-battery. The investigated core is a battery type small modular reactor, graphite moderated, uranium fueled, prismatic, helium cooled high-temperature gas cooled reactor with graphite reflector. The two core alternative designs were investigated. The first has a central reflector and 30×4 prismatic fuel blocks and the second has no central reflector and 37×4 blocks. The SERPENT Monte Carlo reactor physics computer code, with ENDF and JEFF nuclear data libraries, was applied. Several nuclear design static criticality calculations were performed and compared with available reference results. The analysis covered the single assembly models and full core simulations for two geometry models: homogenous and heterogenous (explicit). A sensitivity analysis of the reflector graphite density was performed. An acceptable agreement between calculations and reference design was obtained. All calculations were performed for the fresh core state.

Open access

Marek Krawczyk, Michał Grąt, Karolina Grąt, Karolina Wronka, Maciej Krasnodębski, Jan Stypułkowski, Łukasz Masior, Wacław Hołówko, Joanna Ligocka, Paweł Nyckowski, Tadeusz Wróblewski, Rafał Paluszkiewicz, Waldemar Patkowski, Krzysztof Zieniewicz, Leszek Pączek, Piotr Milkiewicz, Urszula Ołdakowska-Jedynak, Bogusław Najnigier, Krzysztof Dudek, Piotr Remiszewski, Ireneusz Grzelak, Oskar Kornasiewicz, Marcin Kotulski, Piotr Smoter, Mariusz Grodzicki, Michał Korba, Piotr Kalinowski, Michał Skalski, Krzysztof Zając, Rafał Stankiewicz, Marta Przybysz, Bartosz Cieślak, Łukasz Nazarewski, Małgorzata Nowosad, Konrad Kobryń, Michał Wasilewicz, Joanna Raszeja-Wyszomirska, Jolanta Piwowarska, Dorota Giercuszkiewicz, Joanna Sańko-Resmer, Sławomir Rejowski, Monika Szydłowska-Jakimiuk, Barbara Górnicka, Bogna Wróblewska-Ziarkiewicz, Michał Mazurkiewicz, Grzegorz Niewiński, Jacek Pawlak and Ryszard Pacho


Liver transplantation is a well-established treatment of patients with end-stage liver disease and selected liver tumors. Remarkable progress has been made over the last years concerning nearly all of its aspects.

The aim of this study was to evaluate the evolution of long-term outcomes after liver transplantations performed in the Department of General, Transplant and Liver Surgery (Medical University of Warsaw).

Material and methods. Data of 1500 liver transplantations performed between 1989 and 2014 were retrospectively analyzed. Transplantations were divided into 3 groups: group 1 including first 500 operations, group 2 including subsequent 500, and group 3 comprising the most recent 500. Five year overall and graft survival were set as outcome measures.

Results. Increased number of transplantations performed at the site was associated with increased age of the recipients (p<0.001) and donors (p<0.001), increased rate of male recipients (p<0.001), and increased rate of piggyback operations (p<0.001), and decreased MELD (p<0.001), as well as decreased blood (p=0.006) and plasma (p<0.001) transfusions. Overall survival was 71.6% at 5 years in group 1, 74.5% at 5 years in group 2, and 85% at 2.9 years in group 3 (p=0.008). Improvement of overall survival was particularly observed for primary transplantations (p=0.004). Increased graft survival rates did not reach the level of significance (p=0.136).

Conclusions. Long-term outcomes after liver transplantations performed in the Department of General, Transplant and Liver Surgery are comparable to those achieved in the largest transplant centers worldwide and are continuously improving despite increasing recipient age and wider utilization of organs procured from older donors.

Open access

Marek Krawczyk, Michał Grąt, Krzysztof Barski, Joanna Ligocka, Arkadiusz Antczak, Oskar Kornasiewicz, Michał Skalski, Waldemar Patkowski, Paweł Nyckowski, Krzysztof Zieniewicz, Ireneusz Grzelak, Jacek Pawlak, Abdulsalam Alsharabi, Tadeusz Wróblewski, Rafał Paluszkiewicz, Bogusław Najnigier, Krzysztof Dudek, Piotr Remiszewski, Piotr Smoter, Mariusz Grodzicki, Michał Korba, Marcin Kotulski, Bartosz Cieślak, Piotr Kalinowski, Piotr Gierej, Mariusz Frączek, Łukasz Rdzanek, Rafał Stankiewicz, Konrad Kobryń, Łukasz Nazarewski, Dorota Leonowicz, Magdalena Urban-Lechowicz, Anna Skwarek, Dorota Giercuszkiewicz, Agata Paczkowska, Jolanta Piwowarska, Remigiusz Gelo, Paweł Andruszkiewicz, Anna Brudkowska, Renata Andrzejewska, Grzegorz Niewiński, Beata Kilińska, Aleksandra Zarzycka, Robert Nowak, Cezary Kosiński, Teresa Korta, Urszula Ołdakowska-Jedynak, Joanna Sańko-Resmer, Bartosz Foroncewicz, Jacek Ziółkowski, Krzysztof Mucha, Grzegorz Senatorski, Leszek Pączek, Andrzej Habior, Robert Lechowicz, Sławomir Polański, Elżbieta Leowska, Ryszard Pacho, Małgorzata Andrzejewska, Olgierd Rowiński, Sławomir Kozieł, Jerzy Żurakowski, Bogna Ziarkiewicz-Wróblewska, Barbara Górnicka, Piotr Hevelke, Bogdan Michałowicz, Andrzej Karwowski and Jerzy Szczerbań

1000 Liver Transplantations at the Department of General, Transplant and Liver Surgery, Medical University of Warsaw - Analysis of Indications and Results

The aim of the study was to analyze indications and results of the first one thousand liver transplantations at Chair and Clinic of General, Transplantation and Liver Surgery, Medical University of Warsaw.

Material and methods. Data from 1000 transplantations (944 patients) performed at Chair and Clinic of General, Transplantation and Liver Surgery between 1994 and 2011 were analyzed retrospectively. These included 943 first transplantations and 55 retransplantations and 2 re-retransplantations. Frequency of particular indications for first transplantation and retransplantations was established. Perioperative mortality was defined as death within 30 days after the transplantation. Kaplan-Meier survival analysis was used to estimate 5-year patient and graft survival.

Results. The most common indications for first transplantation included: liver failure caused by hepatitis C infection (27.8%) and hepatitis B infection (18%) and alcoholic liver disease (17.7%). Early (< 6 months) and late (> 6 months) retransplantations were dominated by hepatic artery thrombosis (54.3%) and recurrence of the underlying disease (45%). Perioperative mortality rate was 8.9% for first transplantations and 34.5% for retransplantations. Five-year patient and graft survival rate was 74.3% and 71%, respectively, after first transplantations and 54.7% and 52.9%, respectively, after retransplantations.

Conclusions. Development of liver transplantation program provided more than 1000 transplantations and excellent long-term results. Liver failure caused by hepatitis C and B infections remains the most common cause of liver transplantation and structure of other indications is consistent with European data.