DIAGNOSTYKA PROCESU SPALANIA Z WYKORZYSTANIEM ANALIZY ZMIAN INTENSYWNOŚCI ŚWIECENIA PŁOMIENIA

Monitoring of the combustion process is carried out in order to ensure its efficiency and stability. Selected aspects of the combustion process diagnostics using the analysis of changes in flame luminosity for two configurations: 100% pulverized coal fuel and a mixture of 80% coal and 20% biomass were presented in the article. The analysis of measurement data was conducted using selected statistical tools and a multiresolution analysis of signals.Monitoring procesu spalania jest prowadzony w celu zapewnienia efektywności i stabilności przebiegu procesu. W artykule przedstawiono wybrane aspekty diagnostyki procesu spalania z wykorzystaniem analizy sygnałów intensywności świecenia płomienia dla dwóch konfiguracji: paliwa w postaci 100% pyłu węglowego i mieszaniny 80% węgla z 20% biomasą. Analiza danych pomiarowych została przeprowadzone z wykorzystaniem wybranych narzędzi statystycznych oraz analizy wielorozdzielczej sygnałów

ANALIZA TRANSPORTU CIEPŁA W PRZEGRODACH BUDOWLANYCH W WYKORZYSTANIEM NARZĘDZI DO OBLICZENIOWEJ MECHANIKI PŁYNÓW CFD

The article presents the mechanisms of heat exchange in building partitions along with a description of the phenomena occurring there. The methods of heat transport on selected examples of the construction of sandwich building walls were presented and discussed. A review of the methods allowing to determine the heat flux value by means of analytical methods and simulations based on numerical analyzes was carried out. The methodology of solving thermal problems has been presented, indicating the complexity of the phenomena occurring at the contact points of surfaces, for which the correct characteristics should be selected in more than one selected form of determining temperature distributions. Heat transport simulation was performed in ANSYS Fluent 2020 R2 software. The value of the heat flux density flowing through the outer wall of a single-family house located in Lublin, Poland was analytically determined. Three different structural wall solutions were adopted: one, two and three-layer. The obtained results were presented in a tabular manner, allowing for a clear verification of the correctness of the calculations performed with both selected methods.W artykule przedstawiono mechanizmy wymiany ciepła w przegrodach budowlanych wraz z opisem zjawisk tam zachodzących. Przybliżono i omówiono sposoby transportu ciepła na wybranych przykładach konstrukcji warstwowych ścian budowlanych. Przeprowadzono przegląd metod pozwalających na wyznaczenie wartości gęstości strumienia ciepła na drodze metod analitycznych oraz symulacji opartych na analizach numerycznych. Przedstawiono metodologię rozwiązywania zagadnień cieplnych wskazując na złożoność zjawisk zachodzących w miejscach kontaktu powierzchni dla których poprawnej charakterystyki należy przyjąć więcej niż jedną wybraną formę wyznaczenia rozkładów temperatury. Wykonano symulację transportu ciepła w oprogramowania ANSYS Fluent 2020 R2 oraz wyznaczono analitycznie wartość gęstości strumienia ciepła przepływającego przez ścianę zewnętrzną domu jednorodzinnego posadowionego w Lublinie w Polsce. Przyjęto trzy różne pod względem konstrukcyjnym rozwiązania ścian: jedno, dwu i trój warstwowe. Otrzymane wyniki przedstawione zostały w sposób tabelaryczny umożliwiając przejrzystą weryfikację poprawności wykonanych obliczeń obydwoma wybranymi metodami

Karyometric comparison of splenic and gastric marginal zone lymphomas

Background: Marginal zone lymphomas are indolent B-cell lymphomas associated with autoimmunity and chronic inflammation. The two most frequent variants are mucosa associated lymphoid tissues marginal zone lymphomas and splenic marginal zone lymphomas. The aim of the study was to determine if it is possible to classify splenic and gastric lymphomas according to karyometric features

Properties and Strength Prediction Modeling of Green Mortar with Brick Powder Subjected to a Short-Term Thermal Shock at Elevated Temperatures

The cement industry is responsible for 8% of global CO2 production. Therefore, a clear trend has been observed recently to replace to some extent the main binder of cement composites with environmentally friendly or recycled materials with a lower carbon footprint. This paper presents the effect of brick powder (BP) on the physico-chemical and mechanical properties of cement mortars. The effect of a short-term thermal shock on morphology and strength properties of green mortars was investigated. BP addition caused increase in porosity and decrease in compressive and flexural strength of mortars. The best results were obtained for samples with 5% wt. BP addition. Above this addition the strength decreased. The mechanical performance of the samples subjected to thermal loading increased compared to the reference samples, which is the result of a process called as the “internal autoclaving”. The BP addition positively affects the linear shrinkage, leading to its reduction. The lowest linear shrinkage value was achieved by the mortar with the highest BP addition. An intelligent modeling approach for the prediction of strength characteristics, depending on the ultrasonic pulse velocity (UPV) is also presented. To solve the model problem, a supervised machine-learning algorithm in the form of an SVM (support vector machines) regression approach was implemented in this paper. The results indicate that BP can be used as a cement replacement in cement mortars in limited amounts. The amount of the additive should be moderate and tuned to the features that mortars should have

Analysis of Low-Density Heat Flux Data by the Wavelet Method

When evaluating the energy efficiency of buildings and implementing the necessary measures to increase energy efficiency levels, thermal technical characteristics are determined. For this purpose, in situ measurements of the thermal resistance of external enclosing structures were carried out. One of the methods most often used by researchers is the non-destructive method—the heat flow meter (HFM) method regulated by ISO 9869. In the case of surveying a building with a high level of thermal resistance, researchers are faced with low-density heat flux measurements, which is always a difficult task due to significant fluctuations and the influence of external factors on the measurement results. This is due to the fact that it is difficult to determine what is a useful signal and what is a consequence of the effects of non-stationarity and heat transfer conditions. The article provides an example of low-density heat flux measurements when determining the thermal resistance of a building and proposes a data pre-processing procedure that allows for the reduction of heat flux fluctuations, which has a significant impact on the final result at low density. The proposed use of wavelet analysis in the pre-processing of low-density heat flux measurement data makes it possible to reconstruct them or reduce disturbances that occur during research. A comparison of the obtained results with the results of the calculation according to ISO 9869-1 showed a decrease in the standard deviation of the measurements from 5.74 to 2.81%. The results of this study can be used to reduce the noise of low-density heat flux and, as a result, reduce the standard deviation of the measurement when applying the HFM method of determining the thermal resistance of external enclosing structures

Educational and occupational progression – following graduates from the University of Warsaw

The paper presents a methodology for the study of outcomes following graduation. The methodology allows a comprehensive evaluation of graduate educational and career progression by analysis of multiple sources: administrative data, panel surveys and qualitative research. These sources are integral to the research framework created for the study Monitoring the fate of university graduates outcomes using administrative data from Social Insurance Institution records. The system offers low cost employment monitoring of graduates. The application of information from administrative records to social research is of particular interest. The approach, commonly used in Scandinavian countries, is new to Poland. The methodology is demonstrated by following the employment and further study of University of Warsaw graduates

Ścieżki edukacyjne i zawodowe absolwentów Uniwersytetu Warszawskiego

Niniejszy artykuł zawiera opis metodologii badania losów absolwentów szkół wyższych. Przedstawiona koncepcja badania pozwala na kompleksową ocenę procesów edukacyjno-zawodowych absolwentów, dzięki wykorzystaniu różnorodnych źródeł: danych z rejestrów administracyjnych, ilościowych badań opinii oraz badań jakościowych. Badania te są integralnymi elementami systemu badań opracowanego w ramach projektu przeprowadzonego przez Pracownię Ewaluacji Jakości Kształcenia Uniwersytetu Warszawskiego. System ten umożliwia uczelniom niskokosztowe monitorowanie losów absolwentów. Szczególną wartość ma charakterystyka wykorzystania danych pochodzących z rejestrów administracyjnych do badań społecznych. Praktyka ta, powszechna w krajach skandynawskich, w Polsce jest dopiero rozwijana. Opis metodologii uzupełniono wybranymi wynikami badania ścieżek edukacyjnych i zawodowych absolwentów Uniwersytetu Warszawskiego