Friction and endurance of MoS2/ta-C coatings produced by Laser Arc deposition

The tribological behaviour of MoS₂/ta-C double layer coatings deposited by Laser-Arc technology was investigated in vacuum and air. In vacuum environment, the friction coefficient against steel balls varies between 0.005 and 0.02 depending on the contact pressure. At high contact pressures, the friction coefficient is as low as 0.005 and the life time between 340,000 and 500,000 cycles. Furthermore, it is shown that a ta-C base layer improves the performance of MoS₂ coating.Surface analyses were performed before and after the tribological tests by means of SEM, EDX, XRD, and TEM. They show that in the top layer beneath the sliding surface crystallization of the initially quasi-amorphous MoS₂ took place. TEM images also verified an orientation of the basal MoS₂-lattice planes parallel to the surface.     

Optimum tolerance design using component-amount and mixture-amount experiments

The tolerance design problem involves optimizing component and assembly tolerances to minimize the total cost (sum of manufacturing cost and quality loss). Previous literature recommended using traditional response surface methodology (RSM) designs, models, and optimization techniques to solve the tolerance design problem for the worst-case scenario in which the assembly characteristic is the sum of the component characteristics. In this article, component-amount (CA) and mixture-amount (MA) experiment approaches are proposed as more appropriate for solving this class of tolerance design problems. The CA and MA approaches are typically used for product formulation problems, but can also be applied to this type of tolerance design problem. The advantages of the CA and MA approaches over the RSM approach and over the standard, worst-case tolerance-design method are explained. Reasons for choosing between the CA and MA approaches are also discussed. The CA and MA approaches (experimental design, response modeling, and optimization) are illustrated using real examples.     

The Properties of Ammonium Dinitramine (ADN): Part 2: Melt Casting

A melt casting technique for ammonium dinitramine (ADN) and ADN/aluminum was developed. ADN proved relatively easy to cast, when 1% of magnesium oxide was used as a stabilizer and crystallization kernels. Densities of ADN/MgO 99/1 were 92 to 97% of theoretical mean density (TMD) and those of ADN/Al/MgO 64/35/1 were between 95 and 99% of TMD. Sedimentation of Al in the melt was prevented and the particle wetting was ensured by selecting a suitable particle size for Al. No gelling agents or other additives were used. The casting process and factors influencing it are discussed.     

(3He,xn) Reaction Cross-Section Calculations for the Structural Fusion Material 181Ta in the Energy Range of 14–75 MeV

The theoretical neutron-production cross-sections produced by ¹⁸¹Ta(³He,xn)^184?xRe reactions (x = 1–7) for structural fusion material ¹⁸¹Ta in ³He-induced reactions have been performed in the incident ³He energy range of 14–75 MeV. Reaction cross-sections, based on theoretical pre-equilibrium nuclear reaction models, have been calculated theoretically by means of the TALYS 1.6 two component exciton, EMPIRE 3.1 exciton, ALICE/ASH geometry dependent hybrid (GDH) and ALICE/ASH hybrid models. The neutron-production cross-section results of the models have been compared with the each other and against the experimental nuclear reaction data (EXFOR). Except the ¹⁸¹Ta(³He,2n)¹⁸²Re and ¹⁸¹Ta(³He,7n)¹⁷⁷Re reactions, the ALICE/ASH cross-section calculations show generally agreement with the experimental values for all reactions used in this study. The ALICE/ASH–GDH model can be suggested, if the experimental data are unavailable or are improbably to be produced because of the experimental troubles.     

Effects of Wild-Type Starter Culture (Artisanal Strains) on Volatile Profile of Urfa Cheese Made from Ewe Milk

In the present study, the development of volatile flavor compounds in sheep’s milk Urfa cheese made by using three different combinations of wild-type strains including Lactococcus lactis subsp. lactis 1B4, Lactococcus garvieae IMAU 50157, Enterococcus faecium ATCC 19434, Enterococcus durans IMAU 60200, and Enterococcus faecalis KLDSO.034 was investigated over 180 days. Three batches of cheese were made using above strains as follows: Cheese A (strains ATCC 19434+1B4+IMAU 50157); Cheese B (strains IMAU 60200+ATCC 19434+1B4); Cheese C (strains KLDSO.034+ IMAU 60200+ ATCC 19434+1B4+ IMAU 50157). The fourth batch was produced from raw sheep’s milk as control (Cheese D). The volatile compounds were identified using a gas chromatography/mass spectrometry system combined with solid-phase microextraction. In total, 70 volatile compounds were recovered from the cheeses including 10 alcohols (mainly ethanol, 2-methyl-1-propanol, 3-methyl-1-propanol), 20 aldehydes and ketones (mainly 2-pentanone, 2-heptanone), 11 esters (mainly ethyl acetate), 10 acids (mainly acetic acid, 2-hydroxy-4-methyl pentanoic acid), 6 terpenes (mainly α-pinene), and 13 miscellaneous compounds (mainly 3,7-dimethyl-1,6-octadiene). While total aldehydes concentration in the control cheese was higher than those made from combinations of wild-type strains (Cheeses A to C), the concentration of alcohols was lower in the former sample. Regarding other volatile compounds there was no clear differences between the cheeses. Results showed that strain combination A or C (Cheese A or C, respectively) could be employed in the manufacture of Urfa cheese made from pasteurized sheep’s milk. However, to reach a fair judgement on the proper strain combination for Urfa cheese, aroma profile (i.e., active compounds) released by the strains should be laid open in detail.     

Rapid detection of fat adulteration in bakery products using Raman and near-infrared spectroscopies

Adulteration is frequently encountered in the food industry and can be identified using currently available techniques. Infrared and Raman spectroscopic procedures are the most attractive techniques regarding fats and oils. The objective of this study was to determine the adulteration of the fat source (margarine or butter) in bakery products using Raman and near-infrared (NIR) spectroscopies. Margarine and butter samples were purchased at local markets in Turkey and examined using Raman and NIR devices. A mixture (50 % margarine : 50 % butter) of fat samples was examined as well. The NIR and Raman spectral output data of all the fat samples were processed using principal component analysis (PCA). Good classification was obtained for margarine, butter and the 1:1 adulterated mixture. The chosen bakery product (cake) was produced using the same fat samples according to the method of the American Association of Cereal Chemists. Then, the fat fraction was extracted from the cakes with n-hexane. Extracted fat samples from the cakes were examined as before. PCA was applied to Raman and NIR spectral data to achieve the separation of fat sources in the cakes. PCA was also validated in each of the two stages. Significant decomposition was observed in the Raman study in contrast to the NIR study. A chemometric comparison was also applied to processed (baked) fat samples in cakes and purchased samples by PCA to assess the effects of heat treatment on sample spectra. Raman spectroscopy with multivariate analyses such as PCA can be used to detect the adulteration of the fat source in bakery products in a faster and more suitable way than the other methods.     

Evaluation of some of the physical properties of atmospheric plasma treated polypropylene fabric

In this study, atmospheric pressure plasma (APP) treatment was applied to polypropylene (PP) fabric with non‐polymerizing gases, such as air, argon, and nitrogen. Properties of the APP‐treated samples including low‐stress mechanical behavior, air permeability, water vapor permeability, and thermal characteristics were evaluated. Tensile and friction coefficient of the specimens were also measured. The changes in these properties are believed to be closely related to the inter‐fiber and inter‐yarn frictional force induced by the APP. The decrease in the air permeability of the APP‐treated PP fabric was probably because of the plasma action effect on change in fabric surface morphology, which was confirmed by scanning electron microscopy micrographs. The change in the thermal properties of the APP‐treated PP fabric was in good agreement with the earlier findings and can be attributed to the amount of air trapped between the yarns and fibers. This study suggests that the APP treatment can influence the final properties of the PP fabric, and also provides information for developing APP‐treated PP fabric for industrial use.     

Valorisation of almond shell waste in ultrasonic biomordanted dyeing: alternatives to metallic mordants

An agroindustrial waste, outer green shell of almond fruit has been valorised as a novel natural dye using chemical solvent-free extraction, small amount of metallic mordants, one-bath biomordanted dyeing, ultrasonic medium, auxiliary-free dyeing and washing. The main objective of this study is to evaluate biomordants vs. metallic mordants depending on heating system both in extraction and dyeing and to reveal alternatives to metallic mordants. Effects of conventional- and ultrasound-assisted systems on dyeing and fastness properties were investigated. Wool fabrics dyed using metallic mordants (alum, iron II sulphate, copper II sulphate and potassium dichromate) were compared with the samples dyed in conjunction with biomordants [powder of valex (acorn of Quercus ithaburensis ssp. macrolepis), pomegranate (Punica granatum L.) rind, rosemary (Rosmarinus officinalis) and thuja (Thuja orientalis) leaves] in terms of colour yield, colour coordinates and fastness properties. Heating system had significant effects on dyeing and fastness results. Power ultrasound did not present any advantage in colour yield increment while it presented different effects on fastness values depending on mordant and process type of which ultrasound was applied. Some biomordants could be replaced with metallic mordants depending on their types and heating system. They could produce completely different colour gamuts just like metallic mordants.     

Residual acrylic monomer content of denture base resins with different fiber systems

The conversion of monomer to its polymer may not be complete and residual monomer is left over in the polymeric matrix; this, in turn, affects the properties of the polymeric matrix. In this study, we wanted to compare residual monomer content of the unreinforced conventional heat-polymerized and microwave-polymerized acrylic resins with those of fiber-reinforced ones. High performance liquid chromatography was used for the determination of the residual monomer content. Statistical analysis of the results was carried out with a confidence level of 95%. It was observed that conventional heat-polymerized denture base resin resulted in a relatively higher residual monomer content than the microwaved one. Conventional heat-polymerized denture base resin with fiber reinforcement caused an increase in the residual monomer content. Furthermore, the change in the residual monomer content of microwave-polymerized denture base resin with fiber reinforcement was not statistically significant compared with no fiber reinforcement. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Isolation of some luteolin derivatives from Mentha longifolia (L.) Hudson subsp. longifolia and determination of their genotoxic potencies

This study was designed to evaluate the mutagenic and antimutagenic activities of luteolin derivatives (luteolin 7-O-glucoside, luteolin 7-O-rutinoside and luteolin 7-O-glucuronide) isolated from Mentha longifolia (L.) Huds. subsp. longifolia by using Ames Salmonella test (TA 1535 and TA1537 strains). In the antimutagenicity assays, luteolin 7-O-glucoside, luteolin 7-O-rutinoside and luteolin 7-O-glucuronide showed antimutagenic effects on TA1537 and TA1535 strains. The highest inhibition rates for luteolin 7-O-glucoside, luteolin 7-O-rutinoside and luteolin 7-O-glucuronide on TA1537 strain were 84.03%, 87.63% and 67.77%, respectively. Similarly, in the antimutagenicity assays performed with the TA1535 strain, the inhibition rates for luteolin 7-O-glucoside and luteolin 7-O-rutinoside were 23.86% and 23.76% respectively. Our findings showed that the antimutagenic properties of luteolin derivatives on TA1537 and TA1535 strains have been found to be structure dependent. The clarification of differences in antimutagenic potency of these luteolin derivatives based on their structures has been demonstrated in this study.