Formation of optical vortices with all-glass nanostructured gradient index masks

We report the development of microscopic size gradient index vortex masks using the modified stack-and-draw technique. The vortex mask has a form of flat surface all-glass plate. Its functionality is determined by an internal nanostructure composed of two types of soft glass nanorods. The generation of optical vortices with charges 1 and 2 is demonstrated.Qatar National Research Fund (NPRP8-246-1-060); Foundation for Polish Science Team Programme from the funds of European Regional Development Fund under Smart Growth Operational Programme (TEAM TECH/2016-1/1)

Impact of the Coulomb field on charged-pion spectra in few-GeV heavy-ion collisions

In nuclear collisions the incident protons generate a Coulomb field which acts on produced charged particles. The impact of these interactions on charged-pion transverse-mass and rapidity spectra, as well as on pion–pion momentum correlations is investigated in Au + Au collisions at $\sqrt{^{S}NN}$ = 2.4 GeV. We show that the low-m$_{t}$ region (m$_{t}$ < 0.2 GeV / c$^{2}$) can be well described with a Coulomb-modified Boltzmann distribution that also takes changes of the Coulomb field during the expansion of the fireball into account. The observed centrality dependence of the fitted mean Coulomb potential energy deviates strongly from a $A_{part}^{2/3}$ scaling, indicating that, next to the fireball, the non-interacting charged spectators have to be taken into account. For the most central collisions, the Coulomb modifications of the HBT source radii are found to be consistent with the potential extracted from the single-pion transverse-mass distributions. This finding suggests that the region of homogeneity obtained from two-pion correlations coincides with the region in which the pions freeze-out. Using the inferred mean-square radius of the charge distribution at freeze-out, we have deduced a baryon density, in fair agreement with values obtained from statistical hadronization model fits to the particle yields

Guidelines for the manufacture of heavy ductile iron castings

This study is devoted to the analysis of the impact that the basic constituents of ductile iron (carbon and silicon) and spheroidising treatment combined with inoculation exert on the final properties of heavy ductile iron castings. To evaluate the possibility of the application of ductile iron technology in the manufacture of castings for wind power plants, simulations were conducted on cast hubs of the rotor blades for wind turbines. For this type of product, it is necessary to produce castings characterised by a ferritic matrix (over 90% ferrite) and to reduce the amount of pearlite and graphite to a minimum, both of which are considered as the main structural constituents that affect the casting properties. The key guidelines for the manufacture of heavy castings from ductile iron, wind turbines included, were discussed, with particular emphasis placed on the process of spheroidising treatment and inoculation, both of which are aimed at producing in the structure of castings a spheroidal graphite of a size from 5 to 12 mm (class V to VI) and a ferritic structure in an amount exceeding 90%. This article is the result of the work done by Krakodlew S.A to implement research project No. POIG 01.04.00-12-116/12, supported by the National Centre for Research and Development and financed by the European Regional Development Fund, measure 1.4 POIG (Execution of industrial research and development in the company Krakodlew S.A., 2014)

Manufacturing and Recycling Impact on Environmental Life Cycle Assessment of Innovative Wind Power Plant Part 1/2

Wind power plants are considered as an ecologically-clean source of energy. However, manufacturing processes cannot be treated that way. Manufacturing processes consume huge amounts of electrical and thermal energy and significant amount of materials, e.g., steel, polymers, oils, and lubricants. All of the above could be potentially harmful for environment. There are not many works and publications regarding life-cycle analysis of wind power plants. This study’s objective is to use LCA (Life Cycle Assessment) to the manufacturing and utilization of a specific drag force-driven wind turbine. The discussed innovative wind turbine is of the type that assures safety for prosumer application. Drag force-driven turbines become more heavy than other types of lift driven turbines, but at the same time, their characteristic provides opportunity to use easily recyclable materials instead of materials like plastics or composites. The wider look through LCA tools, may change the perspective of view at that type of wind turbines. Analyzed turbine has capacity of 15 kW and is located in Poland. LCA was carried out using Eco-indicator 99 method in eleven impact categories. Among all of the turbine components, the highest negative impact was noted in the case of the tower. The wind turbine under consideration is characterized by high recycling potential. According to the presented research, recycling provides around 30% reduction of the environmental impact

Manufacturing and Recycling Impact on Environmental Life Cycle Assessment of Innovative Wind Power Plant Part 2/2

The process of conversion of wind kinetic energy into electricity in innovative wind power plant emits practically no harmful substances into the environment. However, the production stage of its components requires a lot of energy and materials. The biggest problem during production planning process of an innovative wind power plant is selection of materials and technologies and, consequently, the waste generated at this stage. Therefore, the aim of this publication was to conduct an environmental analysis of the life cycle of elements of a wind turbine by means of life cycle assessment (LCA) method. The object of the research was a wind power plant divided into five sets of components (tower, turbine structure, rotors, generators, and instrumentation), made mainly of steel and small amounts of polymer materials. Eco-indicator 99 was used as an analytical procedure. The impact of the subjects of analysis on human health, ecosystem quality and resources was assessed. Among the analyzed components, the highest level of negative impact on the environment was characterized by the life cycle of the wind turbine tower. The application of recycling processes is reducing the negative impact on the environment in the perspective of the entire life cycle of all studied elements of the wind power plant construction

Formation of optical vortices with all-glass nanostructured gradient index masks

We report a development of microscopic size gradient index vortex masks using modified stack-and-draw technique. Vortex mask has a form of tens of microns thick, flat-surface all-glass plate. Its functionality is determined by internal nanostructure composed of two types of soft glass nanorods. Their spatial arrangement ensures that the average refractive index mimics continuous refractive index distribution imposing azimuthal phase modulation of optical beam. The mask of thickness of 40 microns is used to demonstrate generation of optical vortices with charges 1 and 2, in the femtosecond and cw regimes, respectively.Qatar National Research Fund (NPRP8-246-1-060) and TEAM TECH/2016-1/1 (Foundation for Polish Science Team Programme from the funds of European Regional Development Fund under Smart Growth Operational Programme)