Aerogel insulation materials for industrial installation : properties and structure of new factory-made products

In this article the comparisons of two new factory-made Chinese aerogel products with the Pyrogel® product, all available on the market, are presented. The aerogel products are in a flexible blanket form and all products are dedicated for high temperature applications. The properties of the samples such as their dimension stability, water vapour transmission and water absorption are also described. Additionally the microstructure and chemical composition of the products are analysed using SEM/ EDS (scanning electron microscopy coupled with X-ray energy-dispersive spectroscopy). The differences in the maximum service temperature are presented. The internal self-heating of the aerogel samples is described and is compared to a similar effect observed in mineral wool samples. The results in the change of the thermal properties in a wide range of temperatures (+ 10–600°C) are shown. The obtained results are correlated with the mineral wool data. The correlation shows an advantage in a highefficiency thermal performance of aerogel products compared to other insulation materials at high temperatures

Efektywność energetyczna instalacji wysokotemperaturowych a metoda wyznaczania charakterystyki cieplnej rurowych materiałów termoizolacyjnych

The article describes a method of determining the thermal conductivity coefficient value of high temperature insulation materials (over 100°C up to 800°C), especially of pipe products. Necessary requirements for the pipe test apparatus together with results of pipe apparatus requirement tests have been shown here. Moreover, an example of investment losses related to improper determination of thermal parameters of an insulating material has been presented.Artykuł przedstawia sposób określania współczynnika przewodzenia ciepła dla materiałów/wyrobów do izolacji cieplnej w wysokich temperaturach (powyżej 100°C do 800°C), w szczególności materiałów rurowych. Przedstawiono niezbędne wymagania dla aparatów do badań współczynnika przewodzenia ciepła wyrobów rurowych wraz z wynikami pomiarów właściwości użytkowych aparatu. Przedstawiono przykład strat inwestycyjnych związanymi z niewłaściwym określeniem parametrów cieplnych materiału izolacyjnego

Zależność wydobycia i produkcji kruszyw budowlanych od wybranych wskaźników rozwoju gospodarczego polski

The document presents current methods of forecasting aggregate production, mainly depending on the size and dynamics of changes in GDP. With a view to developing more accurate forecasts, this article presents the dependence of extraction and consumption of mineral aggregates used in construction on two indicators: the general business climate indicator in the construction industry and the cement consumption volume. The results obtained from regression and correlation analysis turned out more favourable for the dependence of aggregates production on cement consumption. This particularly applies to the dependence of sand and gravel aggregate production and total natural aggregate production on cement consumption. Good dependence has also been confirmed for other European countries as well as for the USA. For Poland, the indicator of sand and gravel aggregates production for cement production in recent years was between 9.5 and 12 Mg/Mg. The values of this indicator vary from country to country, mainly depending on the share of different types of aggregates in total production of aggregates in construction industry. Although the indicator values vary considerably, its advantage is that cement production is identified and included in the industrial production balance sheets of most countries, which is not the case when it comes to the identification or accurate record for the production of construction aggregates. The adoption of this indicator makes it possible to monitor the extraction of natural construction aggregates for individual countries and regions more accurately, as called for – among other things - by UN resolutions.Wzrost ludności świata, urbanizacja oraz rozwój gospodarczy i przemysłowy przyczyniają się do ciągłego wzrostu zapotrzebowania na kruszywa mineralne. Szacuje się, że obecna światowa produkcja kruszyw mineralnych wynosi ok. 50 mld Mg, co stanowi ok. 6,5 Mg na statystycznego mieszkańca. Pomimo tak dużej skali, w wielu krajach i regionach świata produkcja kruszyw należy do najmniej uregulowanych sektorów działalności człowieka. Dotyczy to szczególnie krajów Azji, Afryki i Ameryki Południowej, w których to krajach zarówno zasoby jak i wydobycie kruszyw, szczególnie piasków i żwirów nie są monitorowane i ewidencjonowane lub też prowadzone ewidencje są mało dokładne. Nie kontrolowana eksploatacja ma duży wpływ na niekorzystne oddziaływanie na środowisko przyrodnicze, w postaci niszczenia koryt rzek i starorzeczy, erozji wybrzeży morskich, wysychania obszarów uprawnych, itp. Dla uregulowania tej nie korzystnej sytuacji związanej z gospodarką zasobami kruszyw naturalnych, jeden z głównych wniosków Raportu UNEP2019 (agenda ONZ), postuluje konieczność powszechnego wprowadzenia planowania i monitorowania procesu pozyskiwania kruszyw naturalnych. W pracy przedstawiono możliwość monitorowania i prognozowania wydobycia i produkcji kruszyw na podstawie różnych wskaźników rozwoju gospodarczego. Dotychczas podstawowym wskaźnikiem wykorzystywanym do opracowania takich prognoz zarówno w kraju jak i zagranicą był PKB

Computing With Default Logic

Default logic was proposed by Reiter as a knowledge representation tool. In this paper, we present our work on the Default Reasoning System, DeReS, the first comprehensive and optimized implementation of default logic. While knowledge representation remains the main application area for default logic, as a source of large-scale problems needed for experimentation and as a source of intuitions needed for a systematic methodology of encoding problems as default theories we use here the domain of combinatorial problems. To experimentally study the performance of DeReS we developed a benchmarking system, the TheoryBase. The TheoryBase is designed to support experimental investigations of nonmonotonic reasoning systems based on the language of default logic or logic programming. It allows the user to create parameterized collections of default theories having similar properties and growing sizes and, consequently, to study the asymptotic performance of nonmonotonic systems under i..

Transcatheter aortic valve replacement with Lotus and Sapien 3 prosthetic valves: a systematic review and meta-analysis

Background: Frequent occurrence of paravalvular leak (PVL) after transcatheter aortic valve replacement (TAVR) was the main concern with early-generation devices and focused technological improvements. Current systematic review and meta-analysis sought to compare outcomes of TAVR for severe native valve stenosis with next-generation devices: Lotus and Sapien 3. Methods: Electronic databases were screened for studies comparing outcomes of TAVR with Lotus and Sapien 3. In a random-effects meta-analysis, the pooled incidence rates of procedural, clinical and functional outcomes according to VARC-2 definitions were assessed. Results: Eleven observational studies including 2,836 patients (Lotus N=862 vs. Sapien 3 N=1,974) met inclusion criteria. No differences were observed regarding composite endpoints-device success and early safety. Similarly, 30-day mortality, major vascular complications, acute kidney injury and serious bleeding events were similar with both devices. Lotus valve demonstrated 35% reduction of the risk for mild PVL: risk ratio (RR) 0.65, 95% confidence interval (CI): 0.49-0.85, P=0.002; but there were no statistical differences with regard to moderate/severe PVL (RR 0.56, 95% CI: 0.18-1.77, P=0.320). Lotus valves produced significantly higher mean transaortic gradients: mean difference (MD) 0.88 mmHg, 95% CI, 0.24-1.53 mmHg, P=0.007; however, without translation into higher rate of prosthesis-patient mismatch (RR 1.10, 95% CI: 0.82-1.47, P=0.540). As compared to Sapien 3, Lotus device placement was associated with significantly higher rate of permanent pacemaker implantation (RR 2.30, 95% CI: 1.95-2.71, P<0.00001) and cerebrovascular events (RR 1.76, 95% CI: 1.03-2.99, P=0.040). Conclusions: Lotus valve, as compared with Sapien 3, was associated with lower risk for PVL but higher risk for permanent pacemaker implantation and cerebrovascular events