61 research outputs found
Clinical study on resin composite and glass ionomer materials in II class restorations in permanent teeth
Glass ionomer cements (GIC) used for restoration of missing dental structures have high biocompatibility and remineralization potential. However, low mechanical resistance excludes their use for long-term restorations of extensive lesions, particularly o
Meeting the WHO 90% target : antiretroviral treatment efficacy in Poland is associated with baseline clinical patient characteristics
Introduction: Modern combined antiretroviral therapies (cART) allow to effectively suppress HIV-1 viral load, with the 90% virologic success rate, meeting the WHO target in most clinical settings. The aim of this study was to analyse antiretroviral treatment efficacy in Poland and to identify variables associated with virologic suppression.
Methods: Cross-sectional data on 5152 (56.92% of the countrywide treated at the time-point of analysis) patients on cART for more than six months with at least one HIV-RNA measurement in 2016 were collected from 14 Polish centres. Patients’ characteristics and treatment type-based outcomes were analysed for the virologic suppression thresholds of <50 and <200 HIV-RNA copies/ml. CART was categorized into two nucleos(t)ide (2NRTI) plus non-nucleoside reverse transcriptase (NNRTI) inhibitors, 2NRTI plus protease (PI) inhibitor, 2NRTI plus integrase (InI) inhibitor, nucleos(t)ide sparing PI/r+InI and three drug class regimens. For statistics Chi-square and U-Mann Whitney tests and adjusted multivariate logistic regression models were used.
Results: Virologic suppression rates of <50 copies/mL were observed in 4672 (90.68%) and <200 copies/mL in 4934 (95.77%) individuals. In univariate analyses, for the suppression threshold <50 copies/mL higher efficacy was noted for 2NRTI+NNRTI-based combinations (94.73%) compared to 2NRTI+PI (89.93%), 2NRTI+InI (90.61%), nucleos(t)ide sparing PI/r+InI (82.02%) and three drug class regimens (74.49%) (p < 0.0001), with less pronounced but significant differences for the threshold of 200 copies/mL [2NRTI+NNRTI-97.61%, 2NRTI+PI-95.27%, 2NRTI+InI-96.61%, PI/r+InI- 95.51% and 86.22% for three drug class cART) (p < 0.0001). However, in multivariate model, virologic efficacy for viral load <50 copies/mL was similar across treatment groups with significant influence by history of AIDS [OR:1.48 (95%CI:1.01–2.17) if AIDS diagnosed, p = 0.046], viral load < 5 log copies/mL at care entry [OR:1.47 (95%CI:1.08–2.01), p = 0.016], baseline lymphocyte CD4 count ≥200 cells/µL [OR:1.72 (95%CI:1.04–2.78), p = 0.034] and negative HCV serology [OR:1.97 (95%CI:1.29–2.94), p = 0.002]. For viral load threshold <200 copies/mL higher likelihood of virologic success was only associated with baseline lymphocyte CD4 count ≥200 cells/µL [OR:2.08 (95%CI:1.01–4.35), p = 0.049] and negative HCV status [OR:2.84 (95%CI:1.52–5.26), p = 0.001].
Conclusions: Proportion of virologically suppressed patients is in line with WHO treatment target confirming successful application of antiretroviral treatment strategy in Poland. Virological suppression rates depend on baseline patient characteristics, which should guide individualized antiretroviral tre0atment decisions
Structural pathways for ultrafast melting of optically excited thin polycrystalline Palladium films
Due to its extremely short timescale, the non-equilibrium melting of metals
is exceptionally difficult to probe experimentally. The knowledge of melting
mechanisms is thus based mainly on the results of theoretical predictions. This
work reports on the investigation of ultrafast melting of thin polycrystalline
Pd films studied by optical laser pump - X-ray free-electron laser probe
experiments and molecular-dynamics simulations. By acquiring X-ray diffraction
snapshots with sub-picosecond resolution, we capture the sample's atomic
structure during its transition from the crystalline to the liquid state.
Bridging the timescales of experiments and simulations allows us to formulate a
realistic microscopic picture of melting. We demonstrate that the existing
models of strongly non-equilibrium melting, developed for systems with
relatively weak electron-phonon coupling, remain valid even for ultrafast
heating rates achieved in femtosecond laser-excited Pd. Furthermore, we
highlight the role of pre-existing and transiently generated crystal defects in
the transition to the liquid state.Comment: main manuscript 33 pages, 9 figures; supplemental material 19 pages,
13 figures - all in one fil
Energy Productivity of Microinverter Photovoltaic Microinstallation: Comparison of Simulation and Measured Results—Poland Case Study
From 2010 in Europe and from 2019 in Poland, the development of a significant number of photovoltaic (PV) microinstallations have been observed; for example, 1 million PV installations were built in Poland, September 2019–May 2022. A PV microinstallation is typically designed for a household (single-family house). Their capacity and energy productivity should be aligned with energy consumption in a given period, for example, a year (prosumer rules in Poland). The aim of this study is to verify the possibilities and accuracy of the use of PV energy production calculation methods in Polish conditions. The existing methods of calculating the energy produced may be inaccurate due to non-adaptation to terrain conditions, place, wind conditions, representativeness of PV panels in the installation, and many other factors. In the study, the HDKR (Hay, Davies, Klucher, Reindl) method was used based on data from the 0.25-degree (both longitude and latitude) mesh of ERA5 weather conditions. Then, the theoretical energy productivity from PV panels was calculated based on broadly used methods like those used in HOMER software. Statistical verification was done to compare the obtained energy production results from 10 PV panels with real results from microinstallations (energy productivity from each panel measured). The representativeness of the analysis period (one year) over the years was also checked using statistical methods. This is the first study to evaluate energy production from a microinverter installation in real conditions in Central Eastern Europe
Wpływ nadmiernych uzysków solarnych na straty ciepła z zasobnika cwu – studium przypadku
The analysis of a solar installation operation was conducted on the example of a detached house in the Lesser Poland province in Poland. A gas boiler and three flat-plate collectors are located inside the house, which are used for heating water in the hot water tank with a volume of 220 dm3. The installation was established in 2012. The heat measured system (for solar gains) was added in 2014. In 2015–2019 solar heat gains measured per area of absorber were higher than 340 kWh/m2. During a two-week period in June 2015, the insolation on the horizontal plane and the temperature were measured in 4 different points of the hot water tank. On this basis, heat losses from the storage tank were determined, i.e. a decrease in temperature during periods with and without the consumption of hot water by the residents. During this period, a temperature higher than 80°C was observed several times in the hot water tank. In two parts of the hot water tank, rhe determined temperature decreases were used to obtain the heat loss amount. In the analyzed period (2 weeks), 9 days were observed with solar heat gains higher than 9 kWh/day. For these days, the value of heat loss from the solar hot water tank was estimated at over 6 kWh/day. This data corresponds to the actual heat demand for hot water preparation in the building at 7.3 kWh/day. The correlation between daily solar heat gains and solar hot water tank heat losses were also determined. In addition, based on the amount of heat losses, the value of the tank loss coefficient was estimated. The obtained value was compared with the manufacturer’s data and reference data.Analiza aspektów pracy instalacji solarnej została przeprowadzona na przykładzie domu jednorodzinnego w województwie małopolskim w Polsce. W analizowanym budynku jednorodzinnym znajduje się kocioł gazowy i instalacja solarna złożona z trzech płaskich kolektorów słonecznych. Urządzenia te odpowiadają za przygotowanie ciepłej wody użytkowej magazynowanej w zasobniku o pojemności 210 dm3. Instalacja powstała w 2012 roku, w 2014 roku została opomiarowana pod kątem uzysków solarnych. W latach 2015–2019 mierzono uzyski solarne, były one wyższe niż 340 kWh/m2 powierzchni absorbera. Podczas dwutygodniowego okresu w czerwcu 2015 roku mierzono także natężenie promieniowania słonecznego na płaszczyźnie poziomej i temperaturę w 4 różnych punktach zasobnika ciepłej wody. Na tej podstawie określono straty ciepła z zasobnika, tj. spadek temperatury w zasobniku w okresach z i bez poboru ciepłej wody użytkowej przez mieszkańców. W tym okresie zanotowano temperaturę wyższą niż 80°C w zasobniku tylko przez kilka stosunkowo krótkich okresów. Wyznaczone spadki temperatury w dwóch częściach zasobnika ciepłej wody użytkowej użyto do określenia ilościowych strat ciepła. W analizowanym okresie (2 tygodnie) zaobserwowano 9 dni z uzyskami solarnymi wyższymi niż 9 kWh/dzień. Dla tych dni oszacowano wartości strat ciepła z zasobnika na poziomie powyżej 6 kWh/dzień. Dane te korespondują z rzeczywistym zapotrzebowaniem na ciepło do przygotowania ciepłej wody użytkowej w budynku na poziomie 7,3 kWh/dzień. Określono także zależności między dziennymi uzyskami solarnymi a stratami ciepła z zasobnika (korelacja). Ponadto bazując na wielkościowych stratach ciepła, oszacowano wielkość współczynnika strat ciepła z zasobnika. Uzyskaną wartość porównano z danymi producenta i danymi referencyjnymi
Porównanie uzysków ciepła z instalacji solarnej z symulacją – studium przypadku
In Poland an increase in the of number solar thermal collectors is observed in household applications.
For economic and ecological profitability the creation of a solar thermal installation design
in a proper manner is essential.
In order to determine solar installations size, software calculating future solar heat gains is used.
SHW software is an examples of such software. The aim of this work was to compare the simulation
results with the real results of the solar installation operation. The comparison was performed
by an example of a single-family house with flat plate collector installations located in south-east
Poland. This installation supports domestic hot water preparation in a house occupied by four people
(in two-year period of analyses). The additional heat source in this building is a gas boiler.
Solar fraction parameter values were chosen for this comparison. Solar fraction is calculated as
a ratio of solar heat gains used in the domestic hot water preparation process to the heat desired for
domestic hot water preparation. The real results of Solar Fraction turned out to be higher than the
simulation results from May to August (there were many days with Solar Fraction = 1). A difference
of 20–50 percentage points was observed (Solar Fraction). Apart from this period no special
differences were observed. Additionally analyses of differences between solar heat gains calculated by Get Solar simulation
software with real values (for analyzed building) was performed. This simulation analysis was done
before process of building installations.W Polsce obserwuje się wzrost liczby kolektorów słonecznych w zastosowaniach domowych. Dla
opłacalności ekonomicznej i ekologicznej ważne jest właściwe zaprojektowanie instalacji solarnej. W celu
ustalenia wielkości instalacji słonecznych stosuje się oprogramowanie do obliczania przyszłych zysków
ciepła słonecznego. Program SHW jest jednym z przykładów takiego oprogramowania.Celem pracy było porównanie wyników symulacji z rzeczywistymi wynikami pracy instalacji solarnej.
Porównanie przeprowadzono na przykładzie domu jednorodzinnego (z instalacją płaskich kolektorów słonecznych)
położonego w południowo-wschodniej Polsce. Instalacja solarna obsługuje przygotowywanie
ciepłej wody użytkowej w domu zamieszkanym przez cztery osoby (w dwuletnim okresie analizy). Dodatkowym
źródłem ciepła w tym budynku jest kocioł gazowy. Do porównania wybrano wartości parametru
Solar Fraction. Solar Fraction jest obliczany jako stosunek zysków ciepła słonecznego wykorzystywanych
w procesie przygotowania ciepłej wody użytkowej do ciepła pożądanego do przygotowania ciepłej wody
użytkowej. Rzeczywiste wyniki frakcji słonecznej (w skali miesięcznej) okazały się wyższe od wyników
symulacji w okresie od maja do sierpnia (było wiele dni z Solar Fraction = 1). Maksymalna różnica wyniosła
20–50 punktów procentowych (Solar Fraction). Oprócz tego okresu nie zaobserwowano żadnych
szczególnych różnic.
Dodatkowo przeprowadzono analizę osiągniętych różnic między zyskami ciepła słonecznego obliczonymi
przez oprogramowanie symulacyjne Get Solar a wartościami rzeczywistymi (dla analizowanego budynku).
Symulacja ta została wykonana przed procesem budowy instalacji
Metoda temperaturowej weryfikacji solarnych uzysków ciepła w instalacji z kolektorami płaskimi – studium przypadku
Solar collectors are used increasingly in single-family housing. Their popularity depends on many factors, including the price-to-productivity ratio, which in turn results from the development of solar collector technology as well as entire systems. This development consists of many aspects, including those related to the modernization of control systems and measuring of solar collector systems. Currently used systems offer, among others, the ability to determine the approximate solar heat gains using the sensors necessary for normal control of the sensor system. The paper analyzes, on the example of one facility, how such installations work in Polish conditions. An installation consisting of 3 solar collectors has been selected for analysis, supporting the preparation of hot utility water for a single-family residential building. The detailed analysis concerned days with high heat gains compared to the average heat demand for hot water preparation in the building. The temperature verification method (TVM) of the calculated solar heat gains by the solar system controller has been proposed. Then, differences in measurements according to two methods (controller and TVM) have been presented at various characteristic moments of the installation’s operation (start- -up, stop) and during continuous operation. It has been shown that during the day gains measured by the controller can be 15% lower than gains measured by the TVM method. The check has been carried out at a daily sunlight value higher than 4.8 kWh/m2 measured on a horizontal plane. The ratio of heat energy supplied to the domestic hot water storage tank to the measured insolation has been 34%. The sum of annual solar heat gains measured by the controller and TVM differed by 5.2%.W budownictwie jednorodzinnym coraz częściej stosuje się kolektory słoneczne. Ich popularność zależy od wielu czynników, w tym stosunku ceny do wydajności, co z kolei wynika z rozwoju technologii kolektorów słonecznych, a także całych systemów. Na rozwój ten składa się wiele aspektów, w tym związanych z modernizacją układów sterowania i pomiarami systemów kolektorów słonecznych. Obecnie stosowane systemy oferują m.in. możliwość określenia przybliżonych uzysków ciepła słonecznego za pomocą czujników niezbędnych do normalnego sterowania układem pracy systemu. W artykule przeanalizowano, na przykładzie jednego obiektu, jak takiego typu instalacje działają w polskich warunkach. Do analizy wybrano instalację składającą się z 3 kolektorów słonecznych wspomagających przygotowanie ciepłej wody użytkowej dla budynku mieszkalnego jednorodzinnego. Szczegółowa analiza dotyczyła dni z dużymi uzyskami ciepła w porównaniu ze średnim zapotrzebowaniem na ciepło do przygotowania ciepłej wody w budynku. Zaproponowano metodę weryfikacji temperatury (TVM) obliczonych zysków ciepła słonecznego przez regulator systemu solarnego. Następnie przedstawiono różnice w pomiarach prowadzonych dwiema metodami (sterownik PLUM i TVM) w różnych charakterystycznych momentach pracy instalacji (rozruch, zatrzymanie) oraz podczas pracy ciągłej. Wykazano, że w ciągu dnia uzyski ciepła mierzone przez kontroler mogą być o 15% niższe niż uzyski mierzone metodą TVM. Sprawdzenie zostało przeprowadzone przy dziennej wartości nasłonecznienia wyższej niż 4,8 kWh/m2 mierzonego w płaszczyźnie poziomej. Stosunek energii cieplnej dostarczonej do zasobnika ciepłej wody użytkowej do zmierzonego nasłonecznienia wyniósł 34%. Suma rocznych uzysków ciepła słonecznego mierzonych przez regulator i TVM różniła się o 5,2%
Review of Research on the Impact of Changes Resulting from the Hard Coal Mining Sector in Poland on the GDP Value
Energy transition is one of the main objectives of the European Union. Significant changes will mainly affect countries in which significant modifications will have to be made to their energy sources. The process will involve high investment in infrastructure and additional costs of the transformation, such as reduced production (which may affect the GDP value) in the economic sectors involved in the process. The aim of this article is to provide the energy transition community, namely the national economy in general and those involved in planning for structural change in particular, with the key lessons and challenges in researching the impact of production changes in the mining sector. This article also shows the relevance of the mining sector in the economy. Within this area, particular attention is given to the following issues: the impact of economic sectors on the country’s GDP (gross domestic product); the identification of key sectors of the economy using the input–output method; the contribution of coal mining and the mining industry to Poland’s GDP; an analysis of changes in the structure of Poland’s economy using the input–output method; and the use of the input–output method in the context of changing/reducing the supply of economic sectors
Energy Productivity Potential of Offshore Wind in Poland and Cooperation with Onshore Wind Farm
Wind power is the leader in electricity production among the standing RES technologies, both in Poland and in Europe/World. In Poland, so far there are only onshore wind turbines. Their dynamic increase in installed capacity has been observed, especially between 2011 and 2017. This study analyzed the impact of offshore wind energy on the ability of the Polish power system to meet power demands. For this purpose, methods of statistical analysis (of existing onshore and planned offshore technologies) for the determination of wind turbine productivity based on wind speed components data from the ERA5 service were used. For onshore wind turbines, the value of the capacity factor CF(P) in Poland was 25.5% in 2021 and 30.1% in 2022. As a result of the simulation, it was calculated that for the planned offshore wind farms, the capacity factor CF(B) would be 55.6% under 2022 wind speed conditions. The 2022 peak load demands in the Polish system were also analyzed. The quantitative impact of installing 6 GW of offshore wind turbine capacity on the national power system was also identified
Evaluation of Using Gas Turbine to Increase Efficiency of the Organic Rankine Cycle (ORC)
Power conversion systems based on the Organic Rankine Cycle (ORC) have been identified as a potential technology especially in converting low-grade renewable sources or waste heat. However, it is necessary to improve efficiency of ORC systems. This paper focuses on use of low geothermal resources (for temperature range of 80–128 °C and mass flow 100 kg/s) by using modified ORC. A modification of conventional binary power plant is conducted by combining gas turbines to increase quality of steam from a geothermal well. An analysis has been conducted for three different working fluids: R245fa, R1233zd(E) and R600. The paper discusses the impact of parameter changes not only on system efficiency but on other performance indicators. The results were compared with a conventional geothermal Organic Rankine Cycle (ORC). Increasing of geothermal steam quality by supplying exhaust gas from a gas turbine to the installation has a positive effect on the system efficiency and power. The highest efficiency of the modified ORC system has been obtained for R1233zd(E) as a working fluid and it reaches values from 12.21% to 19.20% (depending on the temperature of the geothermal brine). In comparison, an ORC system without gas turbine support reaches values from 9.43% to 17.54%
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