Surface integrity in cryogenic machining of nickel based alloy—Inconel 718

In machining processes, a major quality related output is integrity of the machined part surface. In machining of difficult-to-cut materials, a drastic decrease in tool-life makes the machining process even more difficult. By considering the broader perspective of the machining system tailored towards sustainable operations, in this work an alternative—cryogenic machining is evaluated for machining performance. The surface integrity characteristics of machined surface as a function of depth have been analyzed for different combinations of cooling/lubrication machining conditions. The residual stresses on the machined surface and sub-surface, surface hardness, and surface roughness are among the significant characteristics studied in this work. The results show that cryogenic machining processes can be implemented to improve all major surface integrity characteristics, thus improving the final product quality level.     

Phytochemicals in fruits of two Prunus domestica L. plum cultivars during ripening

BACKGROUND: Plums are a rich source of nutritive and bioactive compounds. The objective was to evaluate the impact of fruit tissue (flesh and peel), ripening stage and cultivar on the composition of phytochemicals in plums (Prunus domestica L.) and to analyse the relation between total antioxidant activity (TAA) and the measured variables. RESULTS: The content of total sugars and total organic acids was higher in flesh but total phenolic content (TPC) and TAA was statistically higher in plum peel. The composition of sugars depended on fruit tissue, ripening stage and the cultivar. Ripening and fruit tissue affected the composition and concentrations of organic acids. TPC of ‘Haganta’ peel increased during ripening but there was no significant time trend for ‘Jojo’ peel and flesh of both cultivars. The composition of phenolics in peel depended on the cultivar, but in flesh on the cultivar and ripening. Ripening resulted in increased total anthocyanins and TAA in peel. TAA_peel was positively correlated with TPC_peel, total anthocyanins_peel, cyanidin 3‐glucoside_peel and peonidin 3‐rutinoside_peel in the cultivar ‘Haganta’. CONCLUSION: The composition of phytochemicals in P. domestica fruit depends on fruit tissue, ripening stage and the cultivar. Peel contributes to the TAA on average 20 times more than flesh. © 2012 Society of Chemical Industry     

Influence of flow field on sedimentation efficiency in a circular settling tank with peripheral inflow and central effluent

The paper presents an experimental study of suspension flow patterns and velocity field inside a circular settling tank with continuous operation. Research was focused on the impact of a specific flow pattern on the sedimentation efficiency of the prototype settling tank. The latter differed from a common circular settling tank in that it was peripherally fed and had the central draw-off. Experiment was carried out on a settling tank section made of plexiglass and represented a radial slice of a prototype settling tank. The flow field and local suspension concentration was determined by computer-aided visualization. Sedimentation efficiency was assessed relatively by comparison of the amount of settled particles (sludge height measurements) between different types of flow in a certain time period of the settling tank operation. Results showed that there were two types of flow in the settling tank that were initiated by a horizontal or vertical inflow from the distribution ring. The type of inflow (horizontal or vertical) was a function of the suspension height in the settling tank. Significant differences in sedimentation efficiency were observed between both types of flow, particularly at lower inlet suspension concentrations. Horizontal inflow proved to be less efficient in terms of settling.     

Investigation of machining performance in high-pressure jet assisted turning of Inconel 718: An experimental study

This paper investigates the application of the high-pressure jet assistance (HPJA) in rough turning of Inconel 718 with coated carbide tools. The region of operability, which sets the boundaries of the process parameters, has been experimentally determined using the tool–material pair (TMP) methodology. The assessment of HPJA machining performance is based on response surface methodology (RSM), which integrates a design of experiment (DOE) and a regression modelling technique for fitting a model to experimental. This leads to a new insight into the influence of the cutting process on chip breakability, cutting forces, contact length, surface finish and tool temperature, which are the key machining performance measures.     

Characterisation of selected hazelnut cultivars: phenology, growing and yielding capacity, market quality and nutraceutical value

BACKGROUND: Sixteen hazelnut cultivars growing in the continental climate of Slovenia were analysed over 15 years for their phenology, growth habit, yield potential, susceptibility to hazelnut weevil and the pomological traits and phenolic content of their nuts in order to obtain a complex value of these cultivars for growers, the confectionary industry and consumers. RESULTS: Blooming occurred over an interval of 10–23 days for female (pistillate) flowers and 11–22 days for male (staminate) flowers. Nocchione, Romai, Pauetet, ID and Daria were the most productive cultivars, with a nine‐year cumulative yield ranging from 31.8 to 44.7 kg per plant. Pauetet, F. Coutard, Nocchione and Segorbe were less susceptible to unfavourable weather conditions during blooming and fertilisation, in terms of maintaining acceptable yields with limited blank production. Under integrated pest management, less than 2% of the nuts of Romai, Daria, TGDL and Nocchione were affected by hazelnut weevil, compared with an average of 5.5% for the other cultivars. Daria, Pauetet and T. Giffoni performed best with regard to kernel percentage and blanching ratio. The results suggest that raw kernels are a good source of the natural antioxidants gallic acid and epicatechin. CONCLUSION: The results of this study provide direction when choosing hazelnut cultivars for planting, consuming or processing. They can be applied not only in Slovenia and nearby countries but also in other parts of central and northern European countries with similar climates and growing conditions. Copyright © 2011 Society of Chemical Industry     

Impact of shelf life on content of primary and secondary metabolites in apple (Malus domestica Borkh.)

In this study, we evaluated the changes in apple fruit quality during shelf life. After a month of cold storage, apples of cultivars "Jonagold" and "Golden Delicious" were exposed to ambient temperatures for 21 d, with subsequent sampling every 3 or 4 d. Fruit firmness, changes in amounts of sugars, malic acid, and phenolics were observed during shelf life. Chemical analyses were done with HPLC-PDA system. An interchange between various sugars was noticed, but in general, the sum of sugars remained at the same level. The content of malic acid remained stable or dropped, resulting in sweeter fruit. Levels of phenolics were more constant in the pulp of both cultivars analyzed, while in the peel, the changes were more pronounced. In the pulp, a peak in the content of hydroxycinnamic acids and flavanols was noticed on the 2nd or 3rd sampling and afterwards, the amounts remained constant. In the peel an initial decrease of all analyzed phenolic groups was observed in both cultivars, however it was more pronounced in "Jonagold." It can be concluded that changes in primary and secondary metabolites are not the main reason for the lower quality of fruit exposed to ambient temperatures. On the other hand, fruit firmness might be the limiting factor for shelf life duration.     

The use of multivariate analysis for evaluating relationships among fat depots in heavy pigs of different genotypes

The aim of the present work was to study distribution and reciprocal relationships of fat depots in heavy pigs of several genetic types. On 161 barrows and gilts belonging to four genetic types (Large White and relative crosses with Italian Landrace, Belgian Landrace and Duroc), slaughtered from 125 to 180 kg l.w., thickness, colour (C.I.E, L*, a*, b*) and weight of backfat and of kidney fat were determined. Subcutaneous and intermuscular fat of ham were weighed. On biceps femoris, semimembranosus and semitendinosus muscles ether extract content was determined. Allometric analysis showed that body growth did not particularly increase the intramuscular fat content of the ham. Principal component analysis indicated that PC1 (0.43% of variation) represented the overall fatness, associated all the depots in a similar manner, and was linked to body weight and sex. PC2 (0.22% of variation), linked to genotypes and body weight, expressed the opposition between intramuscular fat deposition and subcutaneous and internal fat accumulation. Using measurements easily recorded on the side (backfat thickness and colour, percent kidney fat), only the estimate of subcutaneous fat, among ham depots, showed good accuracy (R(2)=0.65).     

Fruit quality of ‘Fuji’ apple (Malus domestica Borkh.) strains

‘Fuji’ is an attractive apple for consumers owing to its desirable internal (low acidity, high sugar and phenols) and external (firmness, colouration) fruit quality. However, its red colouration is often weak and starts late in the season. Therefore, in 2003 and 2004, three ‘Fuji’ strains, ‘Kiku 7’, Kiku 8' and ‘Naga‐fu 6’, and standard ‘Fuji’ were compared in terms of fruit quality by high‐performance liquid chromatography analysis in order to determine their contents of fruit sugar, organic acids and phenols. The % and intensity of red top colour were also analysed. Of the three strains, ‘Kiku 8’ proved to have the best red colouration and accumulated the largest amount of reducing sugars with the lowest quantity of phenols in both years examined. The quality parameters of strains ‘Kiku 7’ and ‘Naga‐fu 6’ fell between those of standard ‘Fuji’ and ‘Kiku 8’. ‘Kiku 8’ may be the most suitable for areas with high variations in daily and nightly temperatures to obtain the best colour development. Under conditions with warm days and cool nights the other strains and standard ‘Fuji’ can develop a proper coloured fruit of high quality. Copyright © 2007 Society of Chemical Industry     

Engineering of Janus-Like Dendrimers with Peptides Derived from Glycoproteins of Herpes Simplex Virus Type 1: Toward a Versatile and Novel Antiviral Platform

Novel antiviral nanotherapeutics, which may inactivate the virus and block it from entering host cells, represent an important challenge to face viral global health emergencies around the world. Using a combination of bioorthogonal copper-catalyzed 1,3-dipolar alkyne/azide cycloaddition (CuAAC) and photoinitiated thiol–ene coupling, monofunctional and bifunctional peptidodendrimer conjugates were obtained. The conjugates are biocompatible and demonstrate no toxicity to cells at biologically relevant concentrations. Furthermore, the orthogonal addition of multiple copies of two different antiviral peptides on the surface of a single dendrimer allowed the resulting bioconjugates to inhibit Herpes simplex virus type 1 at both the early and the late stages of the infection process. The presented work builds on further improving this attractive design to obtain a new class of therapeutics.