Low-Dimensional FeS2 Nanostructures for use as Hydrogen Evolution Electrocatalysts

The water splitting hydrogen evolution reaction which is used as an alternative method of hydrogen production currently relies on platinum group metal electrocatalysts to function. Currently this method accounts for only a small portion of actual hydrogen production. To achieve broad utilization of this method of hydrogen generation it would be beneficial if these precious metal catalysts were replaced with low-cost materials that use easily scalable production methods. Many different materials have been investigated attempting to identify effective replacements for precious metal electrocatalysts and FeS2 nanomaterials are a class of materials that meet these utilization requirements and have a demonstrated catalytic ability. This work examines the synthetic parameters and fundamental reaction mechanism involved in the formation of novel low dimensional iron disulfide nanostructures and subsequently details their development as replacement electrocatalysts. The low-dimensional hyperthin FeS2 nanostructures were generated by a scalable modified hot-injection technique. Maintaining low reaction temperatures kinetically confined the reaction to its early stages. Subsequent manipulation of the sulfur in the reaction allowed for the formation of novel one (1D) and two (2D) dimensional nanostructures which were observed in both transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Furthermore, increased dwell times allowed for stoichiometric control of products to produce a 1:2 Fe:S structure as characterized by energy dispersive X-ray (EDS), X-ray diffraction (XRD), and Raman spectroscopy. Additionally, these nanomaterials did not adhere to the normally observed reaction pathway and formed without undergoing growth through Ostwald ripening or orientated attachment. Electrocatalytic performance of 1D and 2D FeS2 materials coated on a glassy carbon electrode was tested against platinum as well as a common 3D FeS2 structure in a phosphate buffered solution (PBS) at neutral pH using linear sweep voltammetry (LSV). The near zero onset potential of the 2D structures was similar to platinum and both had calculated charge transfer coefficients of 0.71. Exchange current densities calculated using Butler-Volmer equations from best-fit lines yielding 2.2 and 8.0 μA cm-2 for the 2D structures and platinum, respectively. Scanning electrochemical microscopy (SECM) confirmed the formation of hydrogen and subsequent stability test showed stable performance for over 125 hours demonstrating that functional low-dimensional FeS2 nanomaterials are promising platinum electrocatalyst replacement

Generating cooperative question-responses by means of erotetic search scenarios

The concept of cooperative question-responses as an extension of cooperative behaviours used by interfaces for databases and information systems is proposed. A procedure to generate question-responses based on question dependency and erotetic search scenarios is presented. The procedure is implemented in Prolog

Demographic changes in urban and rural communes of the Opoczno district in 1995–2018

The main objective of the article was to identify demographic changes in urban and rural communes of the Opoczno district in 1995–2018. The article traces changes in the population, including natural increase and migration balance using the Webb typology, discusses changes in the population structure by age and gender, as well as the issue of demographic ageing. The Opoczno district mainly undergoes negative demographic processes. There has been a continuous decrease of the population due to both natural and migration loss. There are visible changes in the age structure of the population that indicate the ageing of society. The demographic situation varies across villages and cities as well as individual communes of the Opoczno district. The depopulation in rural and peripheral areas as well as the development of the Opoczno suburban area have become significant.Głównym celem artykułu była identyfikacja zmian demograficznych w gminach miejskich i wiejskich powiatu opoczyńskiego w latach 1995–2018. Przeanalizowane zostały przemiany liczby ludności z uwzględnieniem przyrostu naturalnego i salda migracji za pomocą typologii Webba, zmiany w strukturze wieku i płci ludności, co ukazało zjawisko starzenia się społeczeństwa. W wyniku przeprowadzonych analiz stwierdzono, że powiat opoczyński ulega głównie negatywnym procesom demograficznym. Sytuacja demograficzna inaczej wygląda na wsiach i w miastach oraz w poszczególnych gminach powiatu opoczyńskiego. Skonstatowano też, że uwidoczniły się problemy depopulacji miast i obszarów peryferyjnych, ale także nastąpił rozwój strefy podmiejskiej Opoczna

Severe allograft rejection in an intestinal transplant patient following oral immunoglobulin treatment for chronic norovirus infection : a case report

In an intestinal transplant patient under triple immunosuppression therapy with tacrolimus levels > 10 ng/L, a 2-day oral immunoglobulin therapy given as treatment for chronic norovirus infection was temporally closely associated with the development of severe steroid-resistant acute graft rejection, thus suggesting that oral immunoglobulin might be able to promote a rejection response.Peer reviewe

Anisotropic super-attenuation of capillary waves on driven glass interfaces

Metrological AFM measurements are performed on the silica glass interfaces of photonic band-gap fibres and hollow capillaries. The freezing of attenuated out-of-equilibrium capillary waves during the drawing process is shown to result in a reduced surface roughness. The roughness attenuation with respect to the expected thermodynamical limit is determined to vary with the drawing stress following a power law. A striking anisotropic character of the height correlation is observed: glass surfaces thus retain a structural record of the direction of the flow to which the liquid was submitted

Zamki, pałace i dwory w Polsce – rozmieszczenie i obecne wykorzystanie

The aim of this chapter was to identify castles, palaces and manors in Poland and to characterize them in terms of their distribution, state of preservation, ownership relations and current function. The intermediate aim was to present the process of data collection using GIS, evaluation of the collected data and the software used. The research was carried out as part of a student project. On the basis of the register of immovable monuments of the National Heritage Institute, locations and descriptive information for 4 842 castles, palaces and manors in Poland were collected using ArcGIS Online application. Of all classified objects, nearly 53% are manors, 41% palaces, and 6% castles. Most manors are located in the center of Poland. Palaces dominate in the western part of the country. Castles are located mainly in the south-western part of Poland and to a lesser extent in the north. Among the analyzed monuments, 60% are considered as functioning objects. Nearly half of all castles, palaces and manors included in the project are private objects. The most common current function of the analyzed monuments is residential function (18%)

An Investigation into Intuitionistic Logic with Identity

We define Kripke semantics for propositional intuitionistic logic with Suszko’s identity (ISCI). We propose sequent calculus for ISCI along with cut-elimination theorem. We sketch a constructive interpretation of Suszko’s propositional identity connective

Mitigating spectral leakage and sampling errors in spatial and spectral (S2) imaging

We present a novel method for validating the relative power value (MPI) of the Spatial and Spectral (S2) imaging technique. By applying corrections for spectral leakage and sampling errors we found the MPI determinations to be accurate within 1dB