Application of Adaptive Tuned Magneto-Rheological Elastomer for Vibration Reduction of a Plate by a Variable-Unbalance Excitation

The present study on vibration reduction in systems wherein the excitation frequency is variable designed and fabricated a magnetorheological elastomer (MRE)-based tunable dynamic vibration absorber and evaluated its performance in an experimental manner. The design of an MRE-based adaptive tuned dynamic vibration absorber (ATDVA) involves designing two parts: stiffness and mass. Before designing the MRE-based ATDVA, this study determined the resonance frequency of a target object for vibration reduction. For the design of the ATDVA’s stiffness part, the thickness of specimens was determined by measuring the rate of variation of the MRE’s shear modulus with respect to the MRE’s thickness. The design of the mass part was optimized using sensitivity analysis and genetic algorithms after the derivation of formulas for its magnetic field and mass. Further, upon the application of an electric current to the MRE, its stiffness was measured so that the stiffness of the designed MRE-based ATDVA could be tuned accordingly. Finally, the vibration-reducing performance of the MRE-based ATDVA was evaluated to determine the applicability of the vibration absorber under the condition of variable-frequency excitation.

Titrimetric method determination of the content of the mass part of siliciumin feed additives

The results of the development of the method for determining the mass fraction of silicium in powder samples of feed additives by the titrimetric method are presented in the article. The implementation and validation of the method was carried out with the use of feed additive of mixed type "Mikasil" produced by LLC «Globus», Ukraine. The procedure was reproduced ten times with the determination of the mass fraction of siliciumin two parallel samples. The method is based on the precipitation of silicic acid in the form of silicium-fluoride of potassium, followed by hydrolysis with hot water in the presence of chlorous calcium. The isolated hydro-chloric acid in an amount equivalent to the content of hydro-fluoric acid is titrating with alkali solution in the presence of an indicator. The results of the studies showed that the specified method for determining the mass fraction of silicium meets the standards of accuracy control for this method, namely the standard quadratic deviation (σ) is 0.52, when norm up to 0.7, when determined in two parallel samples. The results obtained indicate that the titrimetric method for determining the mass fraction of silicium in powder samples of feed additives is accurate, reliable, reproducible and economically available.

DELIGNIFICATION OF FLAX SHIVE

Delignification of the flax shive (wastes of oakum and heat insulation production) was studied. Chemical composition of the work material (mass parts in percents from the bone-dry material): cellulose 30,7, lignin 33,1, pentosans 28,0, extractable by organic solvent 4,3, extractable by hot water 5,4, ash 1,7. The flax shive was delignificated in laboratory condition by means of peracetic acid, hydrogen peroxide and sulfate cooking solution. The conditions of peracetic pulping: initial mass part of the «icy» acetic acid in cooking solution 0,65, perhydrol 0,35, the catalyst concentration (sodium tungstate) 0,03 g-mol/dm3, liquid module 6, temperature 92 °C; pulp yield 46,1% without of undercooked pulp. The conditions of peroxide pulping: initial concentration of hydrogen peroxide 17%, liquid module 6, complex catalyst concentration 0,1 g-mol/dm3 (molar parts of the Na2WO4, Na2MoO4 and H2SO4 in catalyst composition are 0,3 : 0,3 : 0,4 accordingly), temperature 98 °C; pulp yield 45,8% without undercooked pulp. The conditions of sulfate pulping: initial concentration of active alkali 55 g/dm3 (in Na2O unit), degree of sulfidity 18%, liquid module 4, temperature 170 °C; pulp yield 32,3% without undercooked pulp. Samples of the technical cellulose, received by oxidizing methods, excel sulphate cellulose in relation to yield, ability for milling, whiteness and mechanical properties (except for tear). On the set of normalized properties they approach to characteristic of kraft bleached pulp from deciduous woods and can be considered as perspective stringy half-finished for production of the paper sanitary-household and hygienic purpose.

Research of kind and quantity of chromic oxide addition influence on alumina-chromia-zirconium silicate refractories properties

Research of pigment chromic oxide addition influence on properties of alumina-chromia-zirconium silicate refractories simples with a mass part 30 and 15 % Cr2O3 got by the semidry pressing method is carried out. It is set, that in samples made from batch with 30 % Cr2O3 optimal quantity of pigment chromic oxide, which provide achieving close properties indexes compared to indexes of samples without this component should be considered 10 %, and in samples made from batch with 15 % Cr2O3 — 6 %. The properties indexes of samples with 30 % Cr2O3 containing 10 % pigment chromic oxide are: mass part of Al2O3 — 62.7 %, Cr2O3 — 30.3 %, ZrO2 — 5.8 %, open porosity 22.6 %, apparent density 3.27 g/cm3, cold crushing strength 123 N/mm2, thermal shock resistance on the mode 950 оC — water 4 thermal cycles, residual changes of sizes at a temperature 1650 оC, exposition 2 hours 0 %. The properties indexes of samples with 15 % Cr2O3 containing 6 % pigment chromic oxide are: mass part of Al2O3 — 76.4 %, Cr2O3 — 15.2 %, ZrO2 — 6.1 %, open porosity 22.4 %, apparent density 3.17 g/cm3, cold crushing strength 145 N/mm2, thermal shock resistance on the mode 950 оC — water 4 thermal cycles, residual changes of sizes at a temperature 1650 оC, exposition 2 hours 0 %. Obtained results are used at making of products for glass melting furnace of industrial lining for fiberglass production from E glass.

The Plasticing Effect on Structure Forming and Crystallization Processes in Polymer Blends of Polypropylene-Poly(Vinyl Alcohol)

There is one established, that glycerol’s injection in (7,0 ÷ 15,0)% of mass. amount into polymer blend of polypropylene/poly(vinyl alcohol) (PP/PVA) of mass equation 30/70% is not changing the structure forming character of PP into PVA matrix: there are parts, films and external shells being formed alongside with PP fibers. When at this, during concentration increase of selective plastifier, there are PP fiber forming process into PP matrix gonna being bad, and those are consisting in average microfiber diameters and mass part of films increase. There are features of structure forming, being linked in plastifying effect of glycerol on the blend melts, and, when simultaneously with, in the those decrease of kinetical stability. There are crystallization temperature of PVA increasing, simultaneously at plasticizer content of 7,0 % of mass., and there is PP crystallization peak absent through polymer amorphization. There is crystallinity’s degree of PP decreases, through high dispersion state of polymer.

Genotypic and paratypic factors formation of milk productivity of austrian schwyz breed cows in environmental area of origin

The article set out the materials of researches about the formation of the level of milk production of Austrian cows of Schwyz breed of different generations, depending on the genotype and paratypic factors at their area of ecological origin, considering of which will promote high selection. It was established that in the operation of animals in the area of environmental origin the level of lactic productivity of daughters varies between 5000 – 12000 kg per lactation, whereas their mothers do not exceed maximum index 12,800 kg, at the same time in the mother of father it exceeds 20000 kg. Thus, the qualitative composition of milk from different generations corresponds to the average consolidated of Schwyz breed. The mass part of the fat and protein in the milk of daughters is at the level 4,13 and 3.57%. The highest content of milk fat in mother of father, the mass of fat in the milk is an average of 4.37%. The dynamics of the implementation of milk production of daughters and their mothers on the continuation of the economic use is similar. In the first lactation the total milk yield of cows amounts respectively 6686.9 and 6261.8 kg of milk, in the second lactation, the level rises to 7532.2, and 7748.7 kg. In the future, there is a slight increase in the productivity and after the fourth lactation daughters and their mother’s milk yield is almost identical and is respectively 8138.3 and 81356 kg of milk. The implementation of the genetic potential of the father's mother passes on a higher level, that meet the requirements for this category of parent. In the first lactation from this cows was obtained 9276.3 kg of milk, and the second – 11599.6 kg. The highest level of productivity was observed in the third lactation where milk yield was an average of 11667.5 kg. After the fourth lactation milk yield decreased slightly, but did not fall below the figure 11139.3 kg. It is proved that the realization of the productive potential of the daughters of parents of highly close to that of a mother. If the productivity of the daughters of the average for the entire period of exploitation below the milk yield of their mothers only 87 kg, 4% milk, the index mother of father – to 3762 kg, or 48.5% (P < 0.001).