Isotope effect in impure high T_c superconductors

The influence of various kinds of impurities on the isotope shift exponent \alpha of high temperature superconductors has been studied. In these materials the dopant impurities, like Sr in La_{2-x}Sr_xCuO_4, play different role and usually occupy different sites than impurities like Zn, Fe, Ni {\it etc} intentionally introduced into the system to study its superconducting properties. In the paper the in-plane and out-of-plane impurities present in layered superconductors have been considered. They differently affect the superconducting transition temperature T_c. The relative change of isotope shift coefficient, however, is an universal function of T_c/T_{c0} (T_{c0} reffers to impurity free system) {\it i.e.} for angle independent scattering rate and density of states function it does not depend whether the change of T_c is due to in- or out-of-plane impurities. The role of the anisotropic impurity scattering in changing oxygen isotope coefficient of superconductors with various symmetries of the order parameter is elucidated. The comparison of the calculated and experimental dependence of \alpha/\alpha_0, where \alpha_0 is the clean system isotope shift coefficient, on T_c/T_{c0} is presented for a number of cases studied. The changes of \alpha calculated within stripe model of superconductivity in copper oxides resonably well describe the data on La_{1.8}Sr_{0.2}Cu_{1-x}(Fe,Ni)_xO_4, without any fitting parameters.Comment: 8 pages, 6 figures, Phys. Rev. B67 (2003) accepte

Measurements, Models, Systems and Design

531 s.

Assessment of climate change and associated impact on selected sectors in Poland

The present paper offers a brief assessment of climate change and associated impact in Poland, based on selected results of the Polish–Norwegian CHASE-PL project. Impacts are examined in selected sectors, such as water resources, natural hazard risk reduction, environment, agriculture and health. Results of change detection in long time series of observed climate and climate impact variables in Poland are presented. Also, projections of climate variability and change are provided for time horizons of 2021–2050 and 2071–2100 for two emission scenarios, RCP4.5 and RCP8.5 in comparison with control period, 1971–2000. Based on climate projections, examination of future impacts on sectors is also carried out. Selected uncertainty issues relevant to observations, understanding and projections are tackled as well

Evidence-based nanoscopic and molecular framework for excipient functionality in compressed orally disintegrating tablets

The work investigates the adhesive/cohesive molecular and physical interactions together with nanoscopic features of commonly used orally disintegrating tablet (ODT) excipients microcrystalline cellulose (MCC) and D-mannitol. This helps to elucidate the underlying physico-chemical and mechanical mechanisms responsible for powder densification and optimum product functionality. Atomic force microscopy (AFM) contact mode analysis was performed to measure nano-adhesion forces and surface energies between excipient-drug particles (6-10 different particles per each pair). Moreover, surface topography images (100 nm2-10 μm2) and roughness data were acquired from AFM tapping mode. AFM data were related to ODT macro/microscopic properties obtained from SEM, FTIR, XRD, thermal analysis using DSC and TGA, disintegration testing, Heckel and tabletability profiles. The study results showed a good association between the adhesive molecular and physical forces of paired particles and the resultant densification mechanisms responsible for mechanical strength of tablets. MCC micro roughness was 3 times that of D-mannitol which explains the high hardness of MCC ODTs due to mechanical interlocking. Hydrogen bonding between MCC particles could not be established from both AFM and FTIR solid state investigation. On the contrary, D-mannitol produced fragile ODTs due to fragmentation of surface crystallites during compression attained from its weak crystal structure. Furthermore, AFM analysis has shown the presence of extensive micro fibril structures inhabiting nano pores which further supports the use of MCC as a disintegrant. Overall, excipients (and model drugs) showed mechanistic behaviour on the nano/micro scale that could be related to the functionality of materials on the macro scale. © 2014 Al-khattawi et al

Comparison of chosen task scheduling algorithms applied at the stage of high level synthesis of digital CMOS circuits

Szeregowanie zadań stosowane dla potrzeb redukcji poboru mocy cyfrowych układów CMOS prowadzi do problemów NP trudnych. Stąd tek, brakuje analitycznych algorytmów gwarantujących uzyskanie optymalnego rozwiązania w akceptowalnym czasie. Praca prezentuje porównanie jakości rozwiązań wyznaczonych heurystycznyini algorytmami szeregowania zadań stosowanych na etapie syntezy wysokiego poziomu cyfrowych układów CMOS, które zostały uzyskane dla wybranego zbioru przykładów testowych. Przedstawione porównanie dotyczy również czasów obliczeń dla wybranych algorytmów szeregowania zadań.Task scheduling applied to reduction of power dissipated in digital CMOS circuits leads to a NP hard problem. Hence, there are no exist analytical algorithms which guarantee a optimal solution in an acceptable computational time. This paper presents a comparison of quality of solutions obtained for a chosen set of benchmarks with different task scheduling heuristic algorithms applied at the stage of high level synthesis of digital CMOS circuits. The presented comparison contains also calculation times for the implemented task scheduling algorithms

Evaluation of the basic properties of the wood waste and wood based wastes

Artykuł ma charakter studium literaturowego, które dotyczy problematyki związanej z powstawaniem odpadów tworzyw drzewnych oraz ich bilansem ilościowym. Ponadto dokonano oceny podstawowych właściwości paliwowych, składu elementarnego i zawartości metali ciężkich w wybranych odpadach drzewnych i drewnopochodnych. Analizą porównawczą objęto dwa rodzaje drewna, tj. świerkowe i bukowe oraz drewno poużytkowe, płyty pilśniowe twarde, płyty wiórowe laminowane - drewnopochodne. Analiza zebranych danych literaturowych miała na celu wskazać różnice i podobieństwa charakterystyczne dla wybranych odpadów. Dane przedstawiono w formie tabelarycznej w celu dokonania analizy porównawczej.The article is a study of literature and refers to the problems related to the generation of the wood wastes and their quantities. Furthermore, it evaluates fuel properties, elemental analysis and content of heavy metals in the selected wood wastes and wood based wastes. Comparative analysis covers two types of wood, i.e. spruce and beech and post -consumed, such as hard fibreboards, laminated chipboard - wood based. The purpose of the analysis of the collected source literature was to indicate differences and similarities characteristic for selected wastes. The results were presented for comparison in a table

Evaluation of the quality of briquettes produced on the basis of corn straw and low density polyethylene

The article presents results of tests of the quality of briquettes. Briquettes made of corn straw and low density polyethylene (PE-LD) were submitted for tests, performed with pre-defined temperature and pressure parameters. In order to evaluate reactions of briquettes during storage, transport and reloading compressive strength, abrasion strength and drop strength were tested. Additionally, tests for water absorbability, water resistance and sorptive properties were included in the experiment. Results of the above tests have been presented in graphic form and listed in a tableW artykule przedstawiono wyniki badań odnośnie jakości brykietów. Badaniom poddano brykiety ze słomy kukurydzy i polietylenu o niskiej gęstości (PE-LD), które wykonano przy założonych parametrach temperatury i ciśnienia. W celu możliwości dokonania oceny zachowywania się brykietów podczas magazynowania, transportu i przeładunku przeprowadzono badania wytrzymałościowe na ściskanie, ścieranie i zrzucanie, które dodatkowo poszerzono o badania pod kątem wyznaczenia stopnia nasiąkliwości, wodoodporności i właściwości sorpcyjnych. Rezultaty powyższych badań zestawiono w formie graficznej i tabelarycznej