Reverse Hierarchy of Alkane Adsorption in Metal–Organic Frameworks (MOFs) Revealed by Immersion Calorimetry

Immersion calorimetry into liquids of different dimensions is a powerful tool to learn about the pore size and shape in nanoporous solids. In general, in the absence of specific interactions with the solid surface, the accessibility of the liquid probe molecule to the inner porosity and the associated enthalpy value decreases with an increase in its kinetic diameter (bulkier molecules have lower accessibility and packing density). Although this is true for the majority of solids (e.g., activated carbons and zeolites), this study anticipates that this is not straightforward in the specific case of metal–organic frameworks (MOFs). The evaluation of different hydrocarbons and their derivatives reveals the presence of reverse selectivity for C6 isomers (2,2-dimethylbutane > 2-methylpentane > n-hexane) in UiO-66 and HKUST-1, whereas size exclusion effects take place in ZIF-8. The immersion calorimetric findings have been compared with vapor adsorption isotherms and computational studies. Monte Carlo simulations suggest that the reverse selectivity in UiO-66 is attributed to the strong confinement of the dibranched hydrocarbons in the small tetragonal cages, whereas the presence of strong interactions with the open metal sites accounts for the preferential adsorption in HKUST-1. These results open the gate toward the application of immersion calorimetry for the prescreening of MOFs to identify in an easy, fast and reliable way interesting characteristics and/or properties such as separation ability, reversed hierarchy, pore-window size, presence of unsaturated metal sites, molecular accessibility, and so on.Authors would like to acknowledge financial support from MINECO (MAT2016-80285-p), Generalitat Valenciana (PROMETEOII/2014/004) and H2020 (MSCA-RISE-2016/NanoMed Project). P.Z.M. is grateful for start-up funds from the University of Sheffield

Sustainable environmental geotechnics practices for a green economy

The revitalisation of the global economy after the Covid-19 era presents environmental geotechnics with the opportunity to reinforce the need for a change in paradigm towards a green, circular economy and to promote aggressively the use and development of sustainable technologies and management practices. This paper aims to assist in this effort by concentrating on several thematic areas where sustainability solutions and future improvements are sought. These include the re-entry of construction and demolition of wastes, excavated materials, industrial wastes and marine sediments into the production cycle and the reuse of existing foundations. Despite the recent trend in advanced countries towards recycling and waste-to-energy thermal treatment, landfills still constitute the most common municipal solid waste management practice, especially in low-and-middle-income countries, and technological solutions to improve their environmental footprint are hereby presented. At the same time, remediation solutions are required to address the multitude of contaminated sites worldwide. Advanced developments that incorporate environmental, economic and social dimensions are expounded by the authors, together with sustainable ground improvement solutions for infrastructure projects conducted in soft and weak soils. The topic of thermo-active geostructures concludes this paper, where, apart from their infrastructure utility, these structures have the potential to contribute to the renewable energy source.Published versionThe second author would like to acknowledge the support of the Office of the Associate Provost for Research and Academic Development at Abu Dhabi University, UAE through grant19300540

Krasicki pozytywistów i modernistów

The author of the article demonstrates the ways of functioning of the biography, intellectual thought and work of Ignacy Krasicki in the literature of the second half of the nineteenth century. References to the literary, ideological and biographical heritage of the poet by positivists and modernists reveal Krasicki’s importance to culture and literature during the second half of the 19th century. The basic goal is to extract from different texts (poet’s biographies, portraits, profiles, studies, synthetic approaches as well as literature - poetry, novels, drama) written by writers, critics and historians of Polish literature, positivism and modernism of modes of references to the shape and heritage of the prince’s poets. The return of positivists and modernists to Krasicki means the possibility of diagnosing one’s own present, and also facilitates defining the identity of culture with its limitations and deficit

Comparative analysis of the quality of Polish banks internet services

W artykule przedstawiono rezultaty analizy porównawczej jakości serwisów internetowych i mobilnych szesnastu największych banków działających na terenie Polski. Analizę przeprowadzono pod kątem wielokryterialnego wyboru najbardziej odpowiedniego serwisu w konkretnych warunkach. Zdefiniowano i wykorzystano w analizie szesnaście różnych kryteriów z trzech obszarów: funkcjonalność i dostępność, innowacyjność oraz bezpieczeństwo. Przy pomocy metody ważonych kryteriów wyznaczono ranking serwisów w każdej z grup kryteriów i dla kryterium końcowego. Analiza wielokryterialna pozwoliła wskazać systemy bankowe o najwyższej jakości.The article presents the results of a comparative analysis of the quality of websites and mobile websites of sixteen largest banks operating in Poland. The analysis was conducted taking into account multiple criteria of choosing the optimal website under certain circumstances. Sixteen different criteria in three different areas have been defined, those areas being: functionality and accessibility, innovation, safety. Using the method of weighted criteria, a ranking has been made in each of the groups and for the final criterion. Multiple-criteria decision analysis allowed the identification of the highest quality banking systems

Thermal conductivity measurement system

Przewodność cieplna metalu jest jednym z ważniejszych parametrów określających jego właściwości metalurgiczne. W pracy przedstawiono automatyczny system pomiaru przewodności cieplnej metali. W systemie wykorzystano oryginalną [2], niestacjonarną metodę pomiaru przewodności cieplnej. Wymuszenie sygnału temperatury w próbce dokonywane jest za pomocą lampy łukowej o regulowanej mocy oraz zespołu luster. Pomiar temperatury na podstawie którego dokonuje się wyznaczenia wartości przewodności cieplnej dokonywany jest za pomocą termopar typu K. Poza wymienionymi elementami system pomiarowy zawiera układ kondycjonowania i transmisji danych firmy National Instruments. W pracy przedstawiono także wyniki eksperymentów pomiarowych potwierdzające poprawną pracę systemu.Thermal conductivity of metal is one of the most significant parameters characterizing its metallurgical properties. The paper describes automatic measurement system destined to thermal conductivity measurements. Such system implements a new original nonstationary method of conductivity determination. The system consists of thermocouple type K, conditioning and transmitting modules: FP-TC 120 and FP 1000 series FieldPoint of National Instruments. It was integrated by LabView environment of NI. Apart of description of system the paper includes results of its test and measurement experiments

The influence of operating conditions on changes in the properties of ventilation pipes made of self-extinguishing polypropylene

The article presents the results of comparative studies of selected mechanical properties (e.g. tensile modulus, tensile stress, notched impact, hardness) of self-extinguishing polypropylene (PPs) samples from three ventilation ducts. The samples were drawn from conduits used for a period of three years inside and outside the building (roof of the building) and, for comparison, from the new conduit. The climatic conditions on which the ventilation duct, placed on the roof, is exposed are temperate climate, group of warm climates, transitional type. Six pieces of samples were prepared for each material from each conduit to determine the mechanical properties. The results of the measurements are also compared with the catalog data provided by two manufacturers of this type of material. Based on the investigations of selected mechanical properties of self-extinguishing polypropylene derived from the operating elements of ventilation ducts, it can be stated that after three years of their use, no significant deterioration of the tested features of the material was observed. However, the impact strength and hardness assays have already shown changes in these properties for samples taken from the ducts used in comparison with the samples from the new duct. These data may indicate that the polypropylene aging process has started as a result of its operation for a period of three years both inside and outside the premises. However, comparing these results with catalog data for plastics dedicated to such applications, the stated changes in some properties do not disqualify the product for further use.W artykule przedstawiono wyniki badań porównawczych wybranych właściwości mechanicznych PPs (polipropylen samogasnący) dla próbek pobranych z trzech przewodów wentylacyjnych. Badaniom poddano próbki pochodzące z przewodów wentylacyjnych pracujących w różnych warunkach. Dla porównania do badań dołączono próbki pobrane z nowych przewodów. W celu wyznaczenia wybranych właściwości mechanicznych wykonywano analizy sześciu równoległych próbek. Wyniki pomiarów zestawiono z danymi katalogowymi podawanymi przez dwóch producentów tego typu elementów

Widening the possibility of modal damping application to diagnostics of large objects

W pracy przedstawiono możliwości zastosowania tłumienia modalnego w diagnostyce dużych obiektów, takich jak: nadwozia samochodów lub kadłuby obiektów pływających i latających. W opisie tłumienia wykorzystano warunek Caughe'ya. Kompozytowy dach samochodu Polonez Kombi przebadano metodą analizy modalnej. Model tłumienia z wykorzystaniem warunku Caughe'ya umożliwia rozprzęganie równań ruchu. Zastosowanie proponowanego modelu tłumienia umożliwia uzyskanie znacznie lepszego przybliżenia właściwości tłumiących struktury kompozytowej (w porównaniu z modelem Rayleigha).The paper presents the possibility of model damping application to diagnostics of the large objects, such how: the body of cars or hulks of swimming and flying objects. Caughey condition is used in description of damping model. the composite roof of the car Polonez Kombi was investigated by Modal Analysis Method. Damping model used Caughey condition make possible decoupling of equations of movement. Application pf proposed damping model make possible getting better approximation of dissipative composite structure proprieties (comparatively by the Rayleigh model)

Phase-amplitude coupling characteristics in directly modulated quantum dot lasers

International audienceWe present a semi-analytical model for studying the phase-amplitude coupling (a-factor) in quantum dot (QD) semiconductor lasers, which takes into account the influence of carrier populations in the excited state and in the two-dimensional carrier reservoir on the refractive index change. Calculations of the a-factor based on the amplified spontaneous emission method and on the "FM/AM" technique are both investigated. It is shown that the a-factor of a QD laser strongly depends on the energy sepa-ration between the ground state and the off-resonant states. Through band structure engineering, the a-factor can be reduced by enlarging this energy separation. V C 2014 AIP Publishing LLC