Dr. Naomi Mandel from Israel, one of this year’s fellows of the Polish Institute of Advanced Studies (PIASt), studies how culture informs technology and, vice-versa, how technology informs culture.
The ceaseless progress of nanotechnology, observed in the last years, causes that nanomaterials are more and more often applied in several
fields of industry, technique and medicine. E.g. silver nanoparticles are used in biomedicine for disinfection and polymer nanoparticles
allow insulin transportation in pharmacology. New generation materials containing nanoparticles are also used in the chemical industry
(their participation in the commercial market equals app. 53 %). Nanomaterials are used in electronics, among others for semiconductors
production (e.g. for producing nanoink Ag, which conducts electric current).
Nanomaterials, due to their special properties, are also used in the foundry industry in metallurgy (e.g. metal alloys with nanocrystalline
precipitates), as well as in investment casting and in moulding and core sand technologies. Nanoparticles and containing them composites
are applied in several technologies including foundry practice, automotive industry, medicine, dentistry etc. it is expected that their role
and market share will be successively growing.
Replacing silicon with diamond may significantly reduce energy losses in electronic devices, according to Dr. Michał Pomorski from the CEA-LIST Diamond Sensors Laboratory in France.
Prof. Hanna Bogucka, head of the Department of Wireless Communications at the Poznań University of Technology, discusses unnecessary inhibitions, the usefulness of microphones, and the links between people and technology.
The nanocomposites based on water glass matrix were attempted in the study. Nanoparticles of ZnO, Al2O3 or MgO in organic solutions
were applied into water glass matrix in the amounts of: 1.5; 3; 4 or 5 mas. %. Wettability of the quartz sad by the nanocomposites based on
water glass matrix was determined by testing changes of the wetting angle θ in time τ for the system: quartz – binder in non-stationary
state, by means of the device for measuring wetting angles. Wettability measurements were carried out under isothermal conditions at an
ambient temperature (20 – 25 oC). The modification improves wettability of quartz matrix by water glass, which is effective in improving
strength properties of hardened moulding sands. Out of the considered modifiers in colloidal solution of propyl alcohol water glass
modified by MgO nanoparticles indicated the smallest values of the equilibrium wetting angle θr. This value was equal app. 11 degrees and
was smaller no less than 40 degrees than θr value determined for not modified water glass. Viscosity η of nanocomposites based on water
glass matrix was determined from the flow curve, it means from the empirically determined dependence of the shearing stress τ on shear
rate γ: τ = f (γ) (1), by means of the rotational rheometer. Measurements were carried out at a constant temperature of 20 oC. The
modification influences the binder viscosity. This influence is conditioned by: amount of the introduced modifier as well as dimensions and
kinds of nanoparticles and organic solvents. The viscosity increase of the modified binder does not negatively influence its functional
properties.
The paper presents results of a simulation of the plasmon effect achieved between a thin precious metal layer and a biconical optical fibre taper, manufactured on a standard single mode fibre. Gold, silver and titanium were used as a metal which fulfilled a cladding function for a small diameter structure. For simulation Mode Solution software was used on which modal and frequency analyses of a wavelength were provided in the range of 800–1700 nm. A displacement of a plasmon pick in dependence of thickness of a deposited precious layer for the highest plasmon effects was observed.
Efforts were made to demonstrate that in biorefineries it is possible to manufacture all the commodities required for maintaining human civilisation on the current level. Biorefineries are based on processing biomass resulting from photosynthesis. From sugars, oils and proteins, a variety of food, feed, nutrients, pharmaceuticals, polymers, chemicals and fuels can further be produced. Production in biorefineries must be based on a few rules to fulfil sustainable development: all raw materials are derived from biomass, all products are biodegradable and production methods are in accordance with the principles of Green Chemistry and Clean Technology. The paper presents a summary of state-of-the-art concerning biorefineries, production methods and product range of leading companies in the world that are already implemented. Potential risks caused by the development of biorefineries, such as: insecurities of food and feed production, uncontrolled changes in global production profiles, monocultures, eutrophication, etc., were also highlighted in this paper. It was stressed that the sustainable development is not only an alternative point of view but is our condition to survive.
The upcoming hypersonic technologies pose a difficult task for air navigation systems. The article presents a designed model of elastic interaction of penetrating acoustic radiation with flat isotropic suspension elements of an inertial navigation sensor in the operational conditions of hypersonic flight. It has been shown that the acoustic transparency effect in the form of a spatial-frequency resonance becomes possible with simultaneous manifestation of the wave coincidence condition in the acoustic field and equality of the natural oscillation frequency of a finite-size plate and a forced oscillation frequency of an infinite plate. The effect can lead to additional measurement errors of the navigation system. Using the model, the worst and best case suspension oscillation frequencies can be determined, which will help during the design of a navigation system.
The work presents the research results of the silumin coat structure applied on the carbidic alloy ductile iron with the metal matrix: pearlitic, bainitic and martensitic. The coats were made in the AlSi5 silumin bath at the temperature tk = 750±5°C. The holding time of cast iron element in the bath was τ = 180s. Irrespective of the kind of tested ductile iron the obtained coat consisted of three layers with a different phase composition. The first layer from the cast iron ground “g1`” is built from Fe4CSi carbide which contains selected alloy additives of the cast iron. On it the second layer “g1``” crystallizes. It consists of the AlFeSi inter-metallic phase which can appear in its pure form or contain a small quantity of the alloy additives of the cast iron. The last external part of the layer “g2” mainly consists of the hypo-eutectic phases of silumin. The AlFeSi inter-metallic phases in the form of free precipitations with a lamellar or faceted morphology can also appear there. These phases also can contain a small quantity of the alloy additives of the cast iron. More than that, in all the layers of the coat there are graphite precipitations. The phenomenon of graphite movement to the coat is caused by intensive dissolving of the cast iron element surface by the aluminum of the silumin bath.
One of the purposes of the application of chemically modified inorganic binders is to improve knocking out properties and the related reclamability with previously used in foundry inorganic binder (water glass), which allowing the use of ecological binders for casting nonferrous metals. Good knocking out properties of the sands is directly related to the waste sands reclamability, which is a necessary condition of effective waste management. Reclamation of moulding and core sands is a fundamental and effective way to manage waste on site at the foundry, in accordance with the Environmental Guidelines. Therefore, studies of reclamation of waste moulding and core sands with new types of inorganic binders (developed within the framework of the project) were carried out. These studies allowed to determine the degree of recovery of useful, material, what the reclaimed sand is, and the degree of its use in the production process. The article presents these results of investigation. They are a part of broader research programme executed under the project POIG.01.01.02-00- 015/09 "Advanced materials and technologies".
Within the research, selected multilayer technological systems created as combinations of water-glass containing moulding sand with
foundry tooling, were characterised on the grounds of their electrical properties. By measuring resonance frequency and quality factor of a
waveguide resonance cavity, real component of permittivity εr′ and loss tangent tgδ were determined for multilayer foundry systems with
various qualitative and quantitative compositions. It was demonstrated that combination of a sandmix and foundry tooling with known
dielectric properties results in a system with different physico-chemical properties, whose relation to the parameters of individual
components of the system is undefined at this research stage. On the grounds of measurement results, theoretical value of microwave
heating power, dissipated in unit volume of the selected multilayer foundry system, was determined. Knowledge of theoretical heating
power and evaluation of physical, chemical and structural changes occurring in moulding sands exposed to microwaves in such a
technological system makes a ground for empirical modelling of the process of microwave heating of foundry moulds and cores.