Improvement of adhesion of conductive polypyrrole coating on wool and polyester fabrics using atmospheric plasma treatment

In this paper wool and polyester fabrics were pretreated with atmospheric plasma glow discharge (APGD) to improve the ability of the substrate to bond with anthraquinone-2-sulfonic acid doped conducting polypyrrole coating. A range of APGD gas mixtures and treatment times were investigated. APGD treated fabrics were tested for surface contact angle, wettability and surface energy change. Effect of the plasma treatment on the binding strength was analyzed by studying abrasion resistance, surface resistivity and reflectance. Investigations showed that treated fabrics exhibited better hydrophilicity and increased surface energy. Surface treatment by an APGD gas mixture of 95% helium/5% nitrogen yielded the best results with respect to coating uniformity, abrasion resistance and conductivity.     

Characterization of bacteriocin-like inhibitory substances (BLIS) from lactic acid bacteria isolated from traditional Azerbaijani cheeses

The lactic acid bacteria (LAB) of southern Caucasus region present a special interest due to the diversity of lactic flora used for fermentations by various local populations during thousands of years. Four LAB strains, not identified previously, isolated from Motal and Brunza typical Azerbaijani cheeses were subjected to phenotypic identification and three of them could be identified as Lactobacillus paracasei subsp. paracasei and one as Lactobacillus rhamnosus. Test strains such as Lactobacillus bulgaricus 340 and Saccharomyces cerevisiae were inhibited by the four isolated strains. Antibacterial activity against Escherichia coli HB 101 was detected in Lactobacillus paracasei BN ATS 8w and L. rhamnosus FAZ 16m. L. paracasei BN ATS 5w and 8w, and L. rhamnosus FAZ 16m showed inhibitory effect on Staphylococcus aureus Cip 9973. The inhibition of Candida pseudotropicalis was detected only when using L. paracasei species BN ATS 5w and 7w. Culture of Listeria innocua was insensitive to the antimicrobial substances of all the studied strains. Complete inactivation or significant reduction in antibacterial activity was observed after treatment of cell-free supernatants with pronase E and proteinase K, but not with trypsin (except for L. rhamnosus FAZ 16m), indicating the protein nature of the active agents. Amylase treatment totally inactivated the substances of L. paracasei, what implies the importance of glycosylation for the activity. The activities of all the bacteriocin-like substances from studied LABs were stable over a wide pH range from 3 to 11.     

Experimental assessment of energy storage via variable speed compressor

In this study, usage of a variable speed refrigeration system in latent heat thermal energy storage (LHTES) system is investigated to increase energy storage efficiency. Four different compressor speed control cases are compared to obtain a constant heat transfer fluid (HTF) temperature at the inlet of the energy storage tank. These control cases are (i) control with evaporation temperature, (ii) control with ethylene glycol temperature at the outlet section of evaporator, (iii) control with suction pressure of the compressor and (iv) on/off control. By means of the experimental analysis the best control strategy is obtained as control with Case (ii), in terms of stability of inlet temperature of heat transfer fluid, variations of energy efficiency of LHTES and coefficient of performance (COP) of the system. While the Case (ii) provides the most stabile inlet temperature of HTF, Case (iv) represents the worst stability. Besides, the highest energy efficiency (99.0%), exergy efficiency (87.0%) and COP (2.05) values observed in Case (ii). Additionally, the time period to reach the set value is nearly 50 min in Case (i), Case (iii) and Case (iv) on the other hand this unstable initial time period becomes nearly 25 min for Case (ii). As a result, variable speed compressor should be controlled with Case (ii) to stabilize ethylene glycol-water solution temperatures as well as increase efficiency and COP of the system.     

Study of oxygen plasma pre-treatment of polyester fabric for improved polypyrrole adhesion

In this work, we have systematically studied the improvement of binding of polypyrrole with polyethylene terephthalate (PET) thin films and fabrics using low pressure oxygen plasma. A range of plasma treatment times were employed to investigate plasma induced effects on surface roughness, surface chemistry and hydrophilicity. Modifications of PET films were studied with respect to surface morphology by means of atomic force and scanning electron microscopy. Chemical effects of plasma treatment were studied using X-ray photoelectron spectroscopy. Results showed that both the increase in surface functionalisation by carboxylic groups and formation of nano size roughness contributed to improved adhesion and conductivity.     

Large thermal biasing of individual gated nanostructures

We demonstrate very large and uniform temperature gradients up to about 1 K every 100 nm, in an architecture which is compatible with the field-effect control of the nanostructure under test. The temperature gradients demonstrated greatly exceed those typically obtainable with standard resistive heaters fabricated on top of the oxide layer. The nanoheating platform is demonstrated in the specific case of a short-nanowire device.     

The effects of diets containing different levels of common vetch (Vicia sativa) seed on fattening performance,carcass and meat quality characteristics of Awassi male lambs

The experiment was carried out to evaluate the effect of common vetch seed (CVS), used at various levels (0, 15 and 25%), as a protein source in diets replacing different proportion of barley, wheat bran and soybean meal on fattening performance, carcass and meat quality characteristics of Awassi male lambs at approximately 8 months of age. The lambs were divided into three treatment groups, T1 (control, fed a diet without CVS; n = 12), T2 (15% CVS; n = 12) and T3 (25% CVS; n = 12), at the beginning of the fattening period. The T2 and T3 lambs were fed with a concentrate including 15 and 25% of ground CVS. The main protein source was soybean meal in T1 diet treatment, partially replaced by vetch in T2 and T3 diet treatments. All groups were fed a diet consisting of concentrate mixture offered ad libitum, and 300 g of grass hay per lamb per day during the 60 day fattening period. Daily feed intake, daily weight gain and feed conversion efficiency (concentrate and hay consumption for 1 kg of live weight gain) were 1.716 kg, 0.26 kg and 6.60 for T1, 1.756 kg, 0.28 kg and 6.27 for T2 and 1.806 kg, 0.29 kg and 6.23 for T3, respectively. Growth, carcass and meat quality traits were almost the same across the groups. In conclusion, CVS supplementation to diets of Awassi lambs at a 0, 15 and 25% rates showed no statistical differences in fattening performance, wholesale cuts of carcasses, meat color parameters (L* = lightness, a* = redness, b* = yellowness, H = huge angle and C = chroma) and pH values, but there were numerical differences (improvement) in feed conversion efficiency. Copyright © 2005 Society of Chemical Industry     

Studying the effect of the temperature factor on the transition from a laminar to a turbulent regime of flow in a boundary layer

Based on the generalization of experimental data, we propose a formula for the calculation of the effect of the temperature factor and the transition from a laminar flow regime to one that is turbulent in the boundary layer of a plate; this formula has been confirmed by experiments performed in the following range of parameter variation: 0.5 2.6; 0.2 M 3.6; 0.1 9%.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 16, No. 2, pp.218–224, February, 1969.