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The article deals with some acoustic properties of materials that have an impact on the sound insulation of building constructions, including sound absorption (abatement). These are namely, the capacity of materials to absorb, i.e. to reduce the sound energy passing through a building construction, the influence of an angle of sound wave incidence onto the partition (construction), etc. Sound pressure on the area of the partition may be uniform, whereas the amplitude of oscillations gets changed throughout the whole area of the partition. The article explores in what cases sound will pass most strongly through the partition of finite dimensions when space-frequency resonance occurs. Investigation showed that the sound energy absorption depended on deformation losses in that material. Changes in the angle of the sound wave incidence at the same frequencies create the opportunity for manifestation of alternation of maximums and minimums in the motion of plate amplitudes. The property of sound wave incidence, at the sound transmission through the plate of finite dimensions, confirms the rightfulness of the division of the curve of the frequency dependence of sound insulation into three ranges of frequencies with the different intensity of sound transmission., in English. Tyrinėjamos medžiagų savybės, kurios turi didžiausią įtaką statybinių konstrukcijų garso izoliacijai. Ištirta medžiagos vidaus trinties nuostolių įtaka garso slopinimui, kai garso energija pereina per statybines konstrukcijas. Plačiau tyrinėjama garso, krintančio į pertvaros bangos kritimo kampą, dažnių įtaka. Nustatyta, kada ir kokiems dažniams esant garso izoliacija geriausia ir kada ji yra prasta, t. y. praleidžia tam tikrų dažnių garsą į kitą konstrukcijos sienelės pusę.

Chemical compounds, composites and raw material mixture compositions expressed by system state diagrams were analysed in this work. The amounts of components % are given, also other parameters (such as temperature, pressure, etc.) can be included. Generally monocomponent (one material, temperature and pressure coordinates), bicomponent (two materials, temperature coordinates) and tetracomponent (three materials, also isotherms can be shown) are used. In this paper, we examined the tetracomponent system state diagram formation, compound or composite composition inclusion into diagrams and also composition identification possibilities. It is shown that the composition can be introduced into the diagram also by the method which could be of interest to patent authors, because some of the information in the diagrams can acquire a “know–how” function., Lietuviška santrauka. Cheminių junginių, kompozitų ir žaliavų mišinių sudėtys būna nurodomos sistemos būsenos diagramose. Jose nurodomi sistemą sudarančių komponentų kiekiai, %, į jas taip pat galima įtraukti ir kitus sistemos parametrus (temperatūrą, slėgį ir t. t.). Paprastai naudojamos vienkomponentės (viena medžiaga, temperatūros ir slėgio koordinatės), dvikomponentės (dvi medžiagos, temperatūros koordinatė), trikomponentės (trys medžiagos, gali būti parodytos ir izotermės). Pasiūlyta keturkomponenčių sistemų būsenos diagrama gali būti taikoma konstrukcinių (metalų, lydinių, keramikos), termoizoliacinių-konstrukcinių ir akustinių (cementinio putbetonio medžiagų), kompozitų, įvairių žaliavų, kitokių medžiagų sudėties analizei. Sudėtys gali būti nustatomos ir tokiu metodu, kuris sudomins patentų autorius, kadangi tam tikra diagramoje esanti informacija gali turėti technologinės naujovės (know-how) funkciją.

The main task of the presented research was to investigate the carbon nanotubes, synthesized from aromatic hydrocarbons and as well as to investigate the possibilities of production and main technological properties of Portland cement based foam concrete reinforced by dispersed carbon nanotubes. The method of stimulation of dehydropolycon-densation and carbonization of aromatic hydrocarbons in chemical active environment (melts of aluminium, copper, nickel, iron salts) was used for carbon nanotubes synthesis. The results of investigation of the synthesized carbon nanotubes by X-ray photoelectron spectroscopy showed that they contain (80 – 90) % of carbon. The examination of the carbon nanotubes microstructure by electron microscope have shown that the nanotubes have a cylindric form, with diameter ranging up to 100 nm and length up to 20 μm. The nanotubes are agglomerated to fiber shaped agglomerates with a diameter up to 30 μm and a length up to 10 mm. The carbon nanotubes were used as a high strength dispersed reinforcement for production of foam non-autoclave concrete produced on the base of Portland cement. The results of the investigation of the reinforced non-autoclave cemente foam concrete showed that the use of carbon nanotubes (0.05 % by mass) in production of these concretes allows to decrease its heat conductivity up to (12 – 20) % and increase its compressive strength up to 70 %.

Examination of literature concerning methods of designing the compositions of composite materials shows that these methods, most of which are empirical and based primarily on a large number of experimental studies and lead to conclusions that, seem to us, to be limited and will suited to the composite material that fiber reinforced composite material is. This paper presents the results of a study on development of compositions having all rheological properties required for composite materials. The fiber reinforced composite is made of matrix and fibers. A high modulus polyethylene fiber was used as the reinforcing fiber. Fiber reinforced composite materials are highly heterogeneous compositions of the dispersion results are often large. To obtain usable information, we made a large number of tests on different specimens and then carrying out a statistical analysis of the results.