The electron density of delocalized bonds (EDDB) applied for quantifying aromaticity

In this study the recently developed electron density of delocalized bonds (EDDB) is used to define a new measure of aromaticity in molecular rings. The relationships between bond-length alternation, electron delocalization and diatropicity of the induced ring current are investigated for a test set of representative molecular rings by means of correlation and principal component analyses involving the most popular aromaticity descriptors based on structural, electronic, and magnetic criteria. Additionally, a qualitative comparison is made between EDDB and the magnetically induced ring-current density maps from the ipsocentric approach for a series of linear acenes. Special emphasis is given to the comparative study of the description of cyclic delocalization of electrons in a wide range of organic aromatics in terms of the kekulean multicenter index KMCI and the newly proposed EDDBk indexThe research was supported in part by the Faculty of Chemistry at Jagiellonian University (grant K/DSC/001469, DS), Foundation for Polish Science (FNP START 2015, stipend 103.2015, DS), National Science Centre, Poland (NCN SONATA, grant 2015/17/ D/ST4/00558, DS) as well as the PL-Grid Infrastructure of the Academic Computer Centre CYFRONET with the calculations performed on the cluster platform ‘‘Prometheus’’. MS thanks for the support of the Ministerio de Economa y Competitividad of Spain (Project CTQ2014-54306-P), Generalitat de Catalunya (project number 2014SGR931, Xarxa de Refere`ncia en Qumica Teo`rica i Computacional, and ICREA Academia prize), and European Fund for Regional Development (FEDER grant UNGI10-4E-801

Pomiary wyższych harmonicznych napięcia w sieci 400 kV

The paper deals with the analysis of voltage harmonics measurements performed in the 400 kV transmission network. The voltage was measured by means of three transducers: resistive voltage divider, inductive measuring transformer and capacitive voltage measuring transformer. Instrument errors were estimated for measuring transformers with reference to the harmonic values obtained from the voltage divider.W artykule przedstawiono analizę wyników pomiarów wyższych harmonicznych napięcia, wykonanych w sieci przesyłowej 400 kV. Sygnały pomiarowe napięć uzyskano z trzech przetworników pomiarowych: rezystancyjnego dzielnika napięcia, napięciowego przekładnika indukcyjnego oraz napięciowego przekładnika pojemnościowego. Wyniki pomiarów z dzielnika rezystancyjnego przyjęto jako referencyjne, odnosząc do nich wyniki pomiarów uzyskane przy wykorzystaniu przekładników. Dokonano oszacowania błędów pomiarowych wyższych harmonicznych napięcia powodowanych przez przekładniki

Toward the emergence of ‘Humane’ Entrepreneurial Ecosystems. Evidences from different cultural contexts

Purpose – Adopting more sustainable and social-oriented perspectives is crucial for the emergence of the so-called 'humane’ entrepreneurial ecosystems (HEEs); the last ones are supporting economic, environmental, and social wealth improvement. Entrepreneurs act as keystone players in each entrepreneurial ecosystem; thus, the emergence of Humane Entrepreneurship (HumEnt) is crucial in shaping HEEs. Given the role of culture in affecting HumEnt, the relationship between Humane Orientation (HO) - as defined in the GLOBE project - and the essential components of Humane Entrepreneurship (HumEnt) was, particularly, explored in a selected sample of countries. Both IC and KM perspectives were adopted in pursuing the research goal. Design/methodology/approach – The study approaches this by the mean of the Ward method with Euclidean squared distance and the k-means method. The GLOBE project, the Global Entrepreneurship Monitor (GEM), the Environmental Performance Index (EPI), and the International Social Survey Programme (ISSP) were used as data sources. Correlations between HO ‘as is’ scores and each component of HumEnt were checked for the world sample (N=36), for the groups of innovation-driven countries (N=17) and European countries (N=14). Findings – Research results show a conditional confirmation of the developed hypotheses, depending on countries' cultural levels of HO, with a moderating role exercised by the economic development on the relationship between culture and HumEnt. Originality/value – Given the increasing pressure of fundamental societal challenges, such as climate change, poverty, and increasing inequality within and between countries intensified by pandemic (UN report, 2021), integrating the more traditional approaches to profit-seeking with the more sustainable and human-centric perspective is a priority for both scholars and society at large. Previous research does not explain the contextual factors responsible for the emergence of more human-oriented entrepreneurial ecosystems, mainly regarding culture. This article broadens our understanding of why both HumEnt and HEEs arise and develop in different cultural contexts

Salix myrsinifolia Salisb. źródłem glikozydów fenolowych: rozmieszczenie i charakterystyka warunków siedliskowych w Polsce środkowowschodniej

In Poland, Salix myrsinifolia Salisb. reaches the south-western border of the dense geographical range. Therefore, the number of natural stands of this species is limited. The aims of this study were: to evaluate the content of phenolic glycosides in darkleaved willow bark taken from natural sites, and to investigate the habitat conditions and natural resources of this species in mid-eastern Poland. In the sites of S. myrsinifolia the annual shoots were taken, and the content of phenolic glycosides in willow bark was determined. The plant communities with the share of this species were characterised, and pH, organic matter, macro- and microelements in soils were determined. The bark of the dark-leaved willow is characterised by a very high content of phenolic glycosides and is considered to be potential natural source of salicylates. The plant communities with share of this species were formed spontaneously on highly transformed calcareous fens where peat was mined and on agriculturally developed peatlands. The number of natural stands is small, and gather from natural habitats is limited. Therefore, this species can be a good source of quality raw material during cultivating.W Polsce Salix myrsinifolia Salisb. osiąga południowo-zachodnią granicę zwartego geograficznego zasięgu, toteż liczba naturalnych stanowisk tego gatunku jest ograniczona. Celem badań było określenie zawartości glikozydów fenolowych w korze wierzby czarniawej ze stanowisk naturalnych, ocena warunków siedliskowych oraz zasobów tego gatunku w Polsce środkowo-wschodniej. W korze pobranej z jednorocznych pędów S. myrsinifolia oznaczono zawartość glikozydów fenolowych. Scharakteryzowano zbiorowiska roślinne z udziałem tego gatunku, a w pobranych próbkach glebowych oznaczono pH, materię organiczną oraz makro- i mikroelementy. Kora wierzby czarniawej charakteryzowała się bardzo wysoką zawartością glikozydów fenolowych i może być traktowana jako potencjalne źródło salicylanów. Zbiorowiska roślinne z udziałem tego gatunku wykształciły się spontanicznie na torfowiskach węglanowych przekształconych w związku z eksploatacją torfu oraz rolniczo zagospodarowanych. Liczba naturalnych stanowisk Salix myrsinifolia jest niewielka, a pozyskiwanie kory ze stanu naturalnego ograniczone. Celowe wydaje się wprowadzenie tego gatunku do uprawy

An analysis of the electricity supply at a public building utilizing photovoltaic systems and a microturbine

W ostatnich latach poszukiwania nowych, efektywnych rozwiązań wytwarzania energii są skierowane na produkcję energii elektrycznej z wykorzystaniem nośników odnawialnych oraz przyjaznych środowisku. Spowodowało to wzrost zainteresowania ogniwami PV oraz systemami kogeneracyjnymi. W artykule, na tle historii rozwoju kolejnych generacji ogniw PV, zaprezentowano główne czynniki wpływające na ich parametry eksploatacyjne. Scharakteryzowano średnie dzienne promieniowanie słoneczne i prędkości wiatru w Łodzi. Przedmiotem badań była stacjonarna i nadążna instalacja fotowoltaiczna o łącznej mocy szczytowej 15 kWp oraz mikroturbina gazowa o mocy elektrycznej 30 kW, znajdujące się na Politechnice Łódzkiej na Wydziału Elektrotechniki, Elektroniki, Informatyki i Automatyki, zasilające sieć elektroenergetyczną budynków laboratoriów. Pomiary energetyczne prowadzono w 2016 roku i na ich podstawie wykonano analizę efektywności energetycznej i analizę finansową zaopatrzenia budynków w energię. Oceniono uzysk energii w modułach stacjonarnych i nadążnych oraz procentowe pokrycie energii elektrycznej z ogniw PV i mikroturbiny. Wyznaczono rozkład miesięcznych oszczędności, roczną oszczędność kosztów energii oraz czas zwrotu kosztów inwestycyjnych badanych systemów. Przeprowadzone badania pozwalają na stwierdzenie, że energia wytworzona przez moduły nadążne jest około 3 razy większa niż wytworzona w modułach stacjonarnych. Natomiast roczne oszczędności kosztów energii przy zastosowaniu mikroturbiny gazowej są około dziesięciokrotnie większe niż dla paneli nadążnych. Po przeprowadzeniu tej analizy można stwierdzić opłacalność stosowania agregatów kogeneracyjnych i paneli fotowoltaicznych, mimo dużych nakładów finansowych. Czas zwrotu nakładów inwestycyjnych wynosi około 12 lat podczas użytkowania instalacji przez cały rok.Recently, the search for new effective energy production solutions has been focused on the production of electricity using renewable and environmentally friendly carriers. This resulted in an increased interest in PV cells and cogeneration systems. The article looks at the main factors affecting their operational parameters against the background of the development history of subsequent generations of PV cells. Average daily solar radiation and wind velocity in Lodz were characterized. The research was done on a static and tracking system with a total peak power of 15 kWp and a 30 kW microturbine. PV panels are installed on the building of the Institute of Electrical Power Engineering of the Lodz University of Technology and they work as part of DERLab. A microturbine is inside the building. Energy measurements were carried out in 2016 giving grounds for the analysis of energy efficiency and financial analysis of the energy supply in buildings. Energy yields in the static and tracking system as well as percentage coverage of electricity from PV cells and microturbines were assessed. The distribution of monthly savings, annual savings of energy costs and the payback time of the investment costs of the systems subject to the test were determined. The research we have done allows us to say that the energy produced by follow-up modules is about 3 times greater than that generated in stationary modules. On the other hand, the annual savings of energy costs using gas micro-turbines are about 10 times higher than those of lagging panels. The analysis shows that it is possible to determine the profitability of the microturbine and photovoltaic panels use despite large financial outlays. The payback period of investment outlays is about 12 years when using the installation throughout the year

Measurements of voltage harmonics in 400 kV transmission network logic

Przedstawiono analizę wyników pomiarów wyższych harmonicznych napięcia wykonanych w sieci przesyłowej 400 kV. Sygnały pomiarowe napięć uzyskano z trzech przetworników pomiarowych: rezystancyjnego dzielnika napięcia, napięciowego przekładnika indukcyjnego oraz napięciowego przekładnika pojemnościowego. Wyniki pomiarów z dzielnika rezystancyjnego przyjęto jako referencyjne odnosząc do nich wyniki pomiarów uzyskane przy wykorzystaniu przekładników. Dokonano oszacowania błędów pomiarowych wyższych harmonicznych napięcia powodowanych przez przekładniki.The paper deals with the analysis of voltage harmonics measurements performed in the transmission network of 400 kV. The voltage was measured by means of three transducers: resistive voltage divider, inductive measuring transformer and capacitive voltage measuring transformer. Instrument errors were estimated for measuring transformers with reference to the harmonic values obtained from the voltage divider

Light alloys for application as engine parts – comparison of properties of three materials

This paper discusses the mechanical properties, microstructure and crystallographic texture of light alloys made on the base of aluminium, magnesium and lithium. An acoustic emission (AE) technique was applied to detect the moment of twinning or slip activation during compression and channel – die tests to extend the comprehension on the nature of the plastic deformation processes occurring in the investigated alloys

Optical and Structural Properties of Cu2O thin Film as Active Layer in Solar Cells Prepared by DC Reactive Magnetron Sputtering

A series of copper oxide thin films were synthesized through direct current magnetron sputtering on glass and silicon substrates with various process parameters. Initially, optical microscopy images and their histograms were analyzed to determine the optical quality of the obtained layers and then histograms were created using Image Histogram Generator software. Next, the morphology, and cross-section and layer composition of the samples were evaluated. Finally, the transmission spectra of the thin films were recorded. Transmittance and reflection spectra of the UV–vis analysis were utilized to calculate the optical band gap, the extinction coefficient, and the absorption coefficient of the oxidized layers. Samples showed low transmittance (up to 40%) in the region of 400 to 1000 nm. The mean absorption coefficient varied from ~3 · 105 to ~6 · 105 1/cm and from ~2 · 105 to ~4 · 105 1/cm in the region of 2 eV to 3.5 eV. The extinction coefficient ranged from 0 to 0.11 in the region from 300 to 3000 nm. Reflectance of the samples was ~20% in the region of 1000 to 2500 nm and ranged from 20%-50% in the region of 1000 to 3000 nm. We verified the process parameters of the Cu2O structure to improve the quality as a buffer layer. On the basis of this preliminary analysis, we propose the most promising and future-oriented solutions in photovoltaic applications

Durability and wear of engine parts – new methods of testing of alloys and composites

The paper deals with the problems related to the diagnostics of selected parts of modern Diesel engines. The evolution of mechanical properties of four alloys of Mg-Li-Al system and four composites made on the base of the alloys mentioned above, caused by variation of its composition was presented. The Acoustic Emission (AE) method applied to monitoring of degradation of mechanical properties of the alloys and composites was described. Moreover, the results of the investigation of failures occurring in the injectors of Common Rail Diesel engines performed with the application of AE method were also reported

Aromaticity of acenes : the model of migrating π\pi-circuits

The concept of migrating Clar's sextet is extended to explain the local aromaticity trends in linear acenes predicted by different aromaticity criteria from theoretical calculations as well as from experimental data. The electron density of delocalized bonds is used to assess the link between resonance and reactivity and to rationalize the constant-height AFM image of pentacen